UPSET PREVENTION & RECOVERY TRAINING - TRANSPORT …

UPSET PREVENTION &RECOVERY TRAINING - TRANSPORT

CATEGORY

COURSE OUTLINES

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UPSET PREVENTION & RECOVERY TRAINING -TRANSPORT CATEGORY

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TABLE OF CONTENT

COURSE START 3

INTRODUCTION - GENERAL 3

Definitions 4

Program Warnings 5

LOW SPEED FLIGHT 10

STALLS 11

CAUSES OF UPSET CONDITIONS 15

Environmentally Induced Upset 15

System Anomalies Induced Upsets 16

Pilot Induced Upsets 17

Combination Of Cause Factors 18

Aerodynamic Factors Leading To Upset Conditions 18

RECOVERY FROM AIRPLANE UPSETS 22

Stallrecovery. 24

Nose High, Wings Level. 24

Nose Low, Wings Level. 25

SUMMARY 27

COURSE END 27



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COURSE START

1-LEGAL CAUTION The material contained in this training program is based on the information obtained from current national, international

and company regulations and it is to be used for training purposes only. At the time of designing this program contained then current

information. In the event of conflict between data provided herein and that in publications issued by the authority, the authority shall take

precedence.

INTRODUCTION - GENERAL

2-Welcome to Airplane Upset Recovery Course. A leading cause of fatalities and hull loses, for transport and normal category aircraft; in

the last two decades is the aircraft loss of control in flight. Aircraft are TYPE certified by the manufactures to meet or exceed the standards

of CS25 and/or FAR Part 25 which assures that the aircraft have been flight tested and approved by the Civil Aviation authorities as being

stable in all three-axis of flight while within the approved aircraft operating. There are many causes for the loss of control while in flight.

This course will attempt to identify some of these risks and provide recovery procedures for the different situations. This program cannot

cover all possible situations that crews might face, although the crews can apply some of the principles identified in this program to assist in

a possible recovery. Airplane Upset Recovery Course must include a combination of a theoretical review of: past upset mishaps, possible

negative aircraft states and how to safely recognise and avoid them; and flight training in simulators to practice the proper procedures to

recover from these conditions in the safest manner. According to ICAO, LOC-I accidents represented only 3 percent of all accidents in

2015, but 33 percent of fatal accidents. International Air Transport Association (IATA) data for 2012-2016 show 30 LOC-I accidents

resulting in 949 fatalities. While the overall rate of occurrence is low, 93 percent of LOC-I accidents result in hull losses and 90 percent

incur fatalities. Some loss of control mishaps: Air France: Air France Flight 447 was a scheduled Air France international passenger flight

from Rio de Janeiro, Brazil, to Paris, France. On 1 June 2009, the Airbus A330 serving the flight stalled and did not recover, eventually

crashing into the Atlantic Ocean at 02:14 UTC, killing all 228 passengers and crew on board. Turkish Corporate Jet: The aircraft,

registered TC-TRB, departed from Sharjah International Airport, United Arab Emirates, at around 17:11 local time (13:11 UTC) bound for

Istanbul Atatürk Airport. The flight crew consisted of two pilots and a cabin attendant. The Captain had flown for Turkish Airlines in the past,

while the First Officer had a military aviation background and had been one of the first female pilots in the Turkish armed forces. The

aircraft reached a cruising altitude of just over 35,000 ft (11,000 m). At around 18:01 IRST local time (14:31 UTC), shortly before contact

was lost, the crew reported technical problems and requested clearance from air traffic control to descend to a lower altitude. The jet began

to climb before abruptly losing altitude, and at 18:09 hit the Zagros Mountains near Shahre Kord, some 370 km (230 mi) south of Tehran,

Iran. All eleven occupants were killed. One witness reportedly saw the aircraft on fire before the crash. Colgan Air Flight: Colgan Air Flight

3407 was marketed as Continental Connection Flight 3407. It was delayed two hours, departing at 9:18 (EST; 02:18 UTC), en route from

Newark Liberty International Airport to Buffalo Niagara International Airport. This was the first fatal accident for a Colgan Air passenger

flight since the company was founded in 1991. One previous ferry flight (no passengers) crashed offshore of Massachusetts in August

2003, killing both of the crew on board. The only prior accident involving a Colgan Air passenger flight occurred at LaGuardia Airport, when

another plane collided with the Colgan aircraft while



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taxiing, resulting in minor injuries to a flight attendant.

3-Some of the limitations to current upset training are: Current training simulators are intended for procedural training for a recovery. These

simulators do not have an accurate ‘feel’ for conditions, which can cause an upset. The simulators don’t have angular velocity and

accelerations and Gs that reproduce actual conditions. This leads to negative training or perception among crews.

4-Upset training in actual transport category aircraft is too dangerous since the pilots are very close to the limits of loss of control. Lighter

aircraft used to teach upset training don’t reproduce the dynamic forces exerted by the larger aircraft. They again teach the procedures for

recovery but not the actual dynamic ‘feel’. It is very difficult to produce the actual ‘startle effect’ of an actual loss of control or weather

phenomena like windshear in the present simulators. Little training is dedicated to identification of the actual condition prior to recovery

procedures are applied.

Definitions

5-DEFINITIONS Undesired aircraft states: ‘Operational conditions where an unintended situation results in a reduction in margins of safety’.

They are a result of ineffective threat and error management This reduced margin of safety is considered the last stage before an incident

or accident occurs.

6-Upset Condition: An airplane upset is an undesired airplane state characterized by unintentional divergences from parameters normally

experienced during operations. An airplane upset may involve pitch and/or bank angle divergences as well as inappropriate airspeeds for

the conditions. Deviations from the desired airplane state will become larger until action is taken to stop the divergence. Return to the

desired airplane state can be achieved through natural airplane reaction to accelerations, auto-flight system response or pilot intervention.

7-Turbulence: Turbulence is characterized by a large variation in an air current over a short distance. It is mainly caused by: * Jetstream *

Convective activity * Mountain Wave * Windshear.

8-Clear Air Turbulence (CAT): Clear air turbulence is defined as ‘high-level turbulence,’ as it is normally above 15,000 MSL. It is not

associated with thunderstorms. CAT is almost always present near jet streams.

9-Mountain Wave Turbulence: Mountains are the greatest obstructions to wind flow. Therefore, this type of turbulence is classified as

‘mechanical’ turbulence. Severe turbulence can be expected in mountainous areas, if the perpendicular wind component exceeds 50 kts

and can be found from the surface up to FL 350.

10-Windshear: Wind variations, in speed and direction, at low altitude are recognized as a serious hazard to airplanes during takeoff and

approach. They can manifest in the form of microbursts or other shear around convective activity or frontal passage.

11-Wake Turbulence: Wake turbulence is a leading cause of airplane upsets that are environmentally induced. The wings create vortices

from the wing tips, which spread down and away from the aircraft and are most severe during takeoff and



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landing. The strength of the turbulence is a function of airplane weight, wingspan, and speed. Vortices descend at an initial rate of 300 to

500 ft./min for about 30 secs to 1 minute.

12-Airplane Icing: Accumulation of any form of frozen moisture on the wing or other surfaces of the aircraft that can add weight and

adversely affect the aerodynamics of flight. Even small amounts of ice/frost can cause an unsafe condition.

13-Angle of Attack: The angle between the chord line of the aircraft wing and the oncoming wind or relative wind.

14-Camber: The amount of curve of the wing on the top surface measured from the centerline of the wing.

15-Wing Dihedral: The angle between the lateral axis of the aircraft and the line that passes through the wing.

16-Energy State: The amount of total energy the aircraft has at any given time.

17-Flight Path: The actual direction and speed of the aircraft.

18-Flight Management Systems: A computer based management systems that contains both navigational and performance information on

the aircraft. It gets information from downloads from the pilots, long and short-range navigational systems and many different system and

sensors on the aircraft.

19-Autoflight Systems: Multiple systems on the aircraft that control flight such as autopilot, autothrottles, air data computers etc.

20-Stability: The tendency of the aircraft to return to normal stable reference when disturbed by some force acting upon the aircraft.

21-Stall: An aircraft stalls when the critical angle of attack is exceeded. At that angle, the aircraft wing is not creating adequate lift for the

aircraft to fly. A stall is characterized by one or more of the following: buffeting, lack of elevator authority, lack of aileron authority and a lack

of ability to stop a descent.

22-Pitch: Movement around the lateral axis

23-Roll: Movement around the longitudinal axis.

24-Yaw: Movement around the vertical axis

Program Warnings

25-PROGRAM WARNINGS This program is intended to identify some of the issues that challenge aviation today. There is no silver bullet

that will stop pilots from getting into upset conditions or allow them to recover from these unexpected situations. Properly recognizing and

reacting to the situation is paramount to a safe recovery. Present training programs cannot adequately train pilots for these situations. For

example, training simulators cannot create conditions such as a heavy rain down shaft on the wings in a windshear or microburst situation,

which could be mis-identified as a stall buffet.



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Each has its own recovery technique but misidentification of the cause can lead to an improper recovery.

26-Training in a non-engineering simulator can lead to the negative transfer of training which creates some bad habits that can be

dangerous in the aircraft. For example, when the rudder is applied fully, multiple times, the procedure can lead to structural failure of the

vertical stabilizer. As little as three full deflections can lead to failure. In some aircraft, as little as 2-3 inches of rudder travel can cause full-

scale rudder deflection without the pilot’s knowledge. When the pilot applies what ‘feels’ like the correct amount of rudder for the condition,

they are actually over-controlling in the actual aircraft. In the training simulator, the reaction appears to be what is needed from recover to

the situation. This leads to negative transfer of training that can be fatal in an actual event. Training simulators are for procedures only,

such as, Windshear, GPWS escape maneuver, but do not accurately reproduce the actual ‘feel’ of the aircraft in those conditions or in the

recovery. Present simulator training does not include ‘startle’ training, or the sudden change in situation awareness due to an unexpected

change in aircraft attitude or the onset of environmental conditions that make the actual determination of the aircraft’s actual energy state

difficult to recognise.

27-Jet Aircraft Aerodynamics The axes of an aircraft are three imaginary lines that pass through an aircraft’s CG. The axes can be

considered as imaginary axles around which the aircraft turns. The three axes pass through the CG at 90° angles to each other. The axis

passes through the CG and parallel to a line from nose to tail is the longitudinal axis, the axis that passes parallel to a line from wingtip to

wingtip is the lateral axis, and the axis that passes through the CG at right angles to the other two axes is the vertical axis. Whenever an

aircraft changes its flight attitude or position in flight, it rotates about one or more of the three axes. The aircraft’s motion about its

longitudinal axis resembles the roll of a ship from side to side. In fact, the names used to describe the motion about an aircraft’s three axes

were originally nautical terms. They have been adapted to aeronautical terminology due to the similarity of motion of aircraft and seagoing

ships.

28-The motion about the aircraft’s longitudinal axis is ‘roll,’ the motion about its lateral axis is ‘pitch,’ and the motion about its vertical axis is

‘yaw.’ Yaw is the left and right movement of the aircraft’s nose.

29-The three motions of the conventional airplane (roll, pitch, and yaw) are controlled by three control surfaces. Roll is controlled by the

ailerons; pitch is controlled by the elevators; yaw is controlled by the rudder. They are added by using trim tabs to help stabilize the aircraft

movements about the flight controls. In some cases, the aircraft auto-trims the aircraft rather than by direct input of the pilots.

30-Aircraft Design Characteristics Each aircraft handles somewhat differently because each resists or responds to control pressures in its

own way. For example, a training aircraft is quick to respond to control applications, while a transport aircraft feels heavy on the controls

and responds to control pressures more slowly. These features can be designed into an aircraft to facilitate the particular purpose of the

aircraft by considering certain stability and maneuvering requirements. The following discussion summarizes the more important aspects of

an aircraft’s stability, maneuverability, and controllability qualities; how they are analyzed and their relationship to various flight conditions.

All aircraft designs, testing and certification confirm the aircraft is safe if operated with in the design limits of the AFM.



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31-Stability Stability is the inherent quality of an aircraft to correct for conditions that may disturb its equilibrium and to return to or to

continue on the original flight path. It is primarily an aircraft design characteristic. The flight paths and attitudes an aircraft flies are limited by

the aerodynamic characteristics of the aircraft, its propulsion system, and its structural strength. These limitations indicate the maximum

performance and maneuverability of the aircraft. If the aircraft is to provide maximum utility, it must be safely controllable to the full extent of

these limits without exceeding the pilot’s strength or requiring exceptional flying ability. If an aircraft is to fly straight and steady along any

arbitrary flight path, the forces acting on it must be in static equilibrium. The reaction of any body when its equilibrium is disturbed is

referred to as stability. The two types of stability are static and dynamic.

32-Static Stability Static stability refers to the initial tendency, or direction of movement, back to equilibrium. In aviation, it refers to the

aircraft’s initial response when disturbed from a given pitch, yaw, or bank. • Positive static stability—the initial tendency of the aircraft to

return to the original state of equilibrium after being disturbed. • Neutral static stability—the initial tendency of the aircraft to remain in a new

condition after its equilibrium has been disturbed. • Negative static stability—the initial tendency of the aircraft to continue away from the

original state of equilibrium after being disturbed.

33-Dynamic Stability Static stability has been defined as the initial tendency to return to equilibrium that the aircraft displays after being

disturbed from its trimmed condition. Occasionally, the initial tendency is different or opposite from the overall tendency, so a distinction

must be made between the two. Dynamic stability refers to the aircraft response over time when disturbed from a given pitch, yaw, or bank.

This type of stability also has three subtypes: • Positive dynamic stability—over time, the motion of the displaced object decreases in

amplitude and, because it is positive, the object displaced returns toward the equilibrium state. • Neutral dynamic stability—once displaced,

the displaced object neither decreases nor increases in amplitude. A worn automobile shock absorber exhibits this tendency. • Negative

dynamic stability—over time, the motion of the displaced object increases and becomes more divergent.

34-Stability in an aircraft affects two areas significantly: • Maneuverability—the quality of an aircraft that permits it to be maneuvered easily

and to withstand the stresses imposed by maneuvers. It is governed by the aircraft’s weight, inertia, size and location of flight controls,

structural strength, and powerplant. It too is an aircraft design characteristic. • Controllability—the capability of an aircraft to respond to the

pilot’s control, especially with regard to flight path and attitude. It is the quality of the aircraft’s response to the pilot’s control application

when maneuvering the aircraft, regardless of its stability characteristics.

35-Maximum speeds in jet airplanes are expressed differently and always define the maximum operating speed of the airplane, which is

comparable to the VNE of the piston airplane. These maximum speeds in a jet airplane are referred to as: • VMO—maximum operating

speed expressed in terms of knots. • MMO—maximum operating speed expressed in terms of a decimal of Mach speed (speed of sound).

36-To observe both limits VMO and MMO, the pilot of a jet airplane needs both an airspeed indicator and a Mach meter, each with

appropriate red lines. In some general aviation jet airplanes, these are combined into a single instrument that



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contains a pair of concentric indicators: one for the indicated airspeed and the other for indicated Mach number. Each is provided with an

appropriate red line. It looks much like a conventional airspeed indicator but has a ‘barber pole’ that automatically moves so as to display

the applicable speed limit at all times.

37-Because of the higher available thrust and very low drag design, the jet airplane can very easily exceed its speed margin even in

cruising flight and, in fact, in some airplanes in a shallow climb. The handling qualities in a jet can change drastically when the maximum

operating speeds are exceeded. If allowed to progress well beyond the MMO for the airplane, this separation of air behind the shock wave

can result in severe buffeting and possible loss of control or ‘upset.’ Because of the changing center of lift of the wing resulting from the

movement of the shock wave, the pilot experiences pitch change tendencies as the airplane moves through the transonic speeds up to and

exceeding MMO.

38-High-speed airplanes designed for subsonic flight are limited to some Mach number below the speed of sound to avoid the formation of

shock waves that begin to develop as the airplane nears Mach 1.0. These shock waves (and the adverse effects associated with them) can

occur when the airplane speed is substantially below Mach 1.0. The Mach speed at which some portion of the airflow over the wing first

equals Mach 1.0 is termed the critical Mach number (Mcr). This is also the speed at which a shock wave first appears on the airplane.

39-There is no particular problem associated with the acceleration of the airflow up to Mach Crit, the point where Mach 1.0 is encountered;

however, a shock wave is formed at the point where the airflow suddenly returns to subsonic flow. This shock wave becomes more severe

and moves aft on the wing as speed of the wing is increased and eventually flow separation occurs behind the well-developed shock wave.

40-Initially as speed is increased up to Mach .72, the wing develops an increasing amount of lift requiring a nose-down force or trim to

maintain level flight. With increased speed and the aft movement of the shock wave, the wing’s center of pressure also moves aft causing

the start of a nose-down tendency or ‘tuck.’ By Mach .9, the nose-down forces are well developed to a point where a total of 70 pounds of

back pressure are required to hold the nose up. If allowed to progress unchecked, Mach tuck may eventually occur. Although Mach tuck

develops gradually, if it is allowed to progress significantly, the center of pressure can move so far rearward that there is no longer enough

elevator authority available to counteract it, and the airplane could enter a steep, sometimes unrecoverable, dive.

41-An alert pilot would have observed the high airspeed indications, experienced the onset of buffeting, and responded to aural warning

devices long before encountering the extreme stick forces shown. However, in the event that corrective action is not taken and the nose is

allowed to drop, increasing airspeed even further, the situation could rapidly become dangerous. As the Mach speed increases beyond the

airplane’s MMO, the effects of flow separation and turbulence behind the shock wave become more severe. Eventually, the most powerful

forces causing Mach tuck are a result of the buffeting and lack of effective downwash on the horizontal stabilizer because of the disturbed

airflow over the wing. This is the primary reason for the development of the T-tail configuration on some jet airplanes, which places the

horizontal stabilizer as far as practical from the turbulence of the wings. Also, because of the critical aspects of high-altitude/high-Mach

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most jet airplanes capable of operating in the Mach speed ranges are designed with some form of trim and autopilot Mach compensating

device (stick puller) to alert the pilot to inadvertent excursions beyond its certificated MMO.

42-Recovery From Overspeed Conditions A pilot must be aware of all the conditions that could lead to exceeding the airplane’s maximum

operating speeds and Good attitude instrument flying skills and good power control are essential.

43-The pilot should be aware of the symptoms that will be experienced in the particular airplane as the VMO or MMO is being approached.

These may include: • Nose-down tendency and need for back pressure or trim. • Mild buffeting as airflow separation begins to occur after

critical Mach speed. • Activation of an overspeed warning or high speed envelope protection.

44-The pilot’s response to an overspeed condition should be to immediately slow the airplane by reducing the power to flight idle. It will also

help to smoothly and easily raise the pitch attitude to help dissipate speed. The use of speed brakes can also aid in slowing the airplane. If,

however, the nose-down stick forces have progressed to the extent that they are excessive, some speed brakes will tend to further

aggravate the nose-down tendency.

45-Under most conditions, this additional pitch down force is easily controllable, and since speed brakes can normally be used at any

speed, they are a very real asset. If the first two options are not successful in slowing the airplane, a last resort option would be to extend

the landing gear, if possible. This creates enormous drag and possibly some nose up pitch. This would be considered an emergency

maneuver. The pilot transitioning into jet airplanes must be familiar with the manufacturers’ recommended procedures for dealing with

overspeed conditions contained in the approved Airplane Flight Manual for the particular make and model airplane.

46-Mach Buffet Boundaries Thus far, only the Mach buffet that results from excessive speed has been addressed. The transitioning pilot,

however, should be aware that Mach buffet is a function of the speed of the airflow over the wing— not necessarily the airspeed of the

airplane. Anytime that too great a lift demand is made on the wing, whether from too fast an airspeed or from too high an angle of attack

(AOA) near the MMO, the ‘high speed buffet’ will occur. However, there are also occasions when the buffet can be experienced at much

slower speeds known as ‘low speed Mach buffet.’

47-The most likely situations that could cause the low speed buffet would be when an airplane is flown at too slow of a speed for its weight

and altitude causing a high AOA. This very high AOA would have the same effect of increasing airflow over the upper surface of the wing to

the point that all of the same effects of the shock waves and buffet would occur as in the high speed buffet situation.

48-The AOA of the wing has the greatest effect on inducing the Mach buffet, or pre-stall buffet, at either the high or low speed boundaries

for the airplane. The conditions that increase the AOA, hence the speed of the airflow over the wing and chances of Mach buffet are: • High

altitudes—The higher the airplane flies, the thinner the air and the greater the AOA required to produce the lift needed to maintain level

flight. • Heavy weights—The heavier the airplane, the greater the lift required of the wing, and all other things being equal, the greater the

AOA. • ‘G’ loading—An increase in the ‘G’ loading of



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the wing results in the same situation as increasing the weight of the airplane. It makes no difference whether the increase in ‘G’ forces is

caused by a turn, rough control usage, or turbulence. The effect of increasing the wing’s AOA is the same.

49-An airplane’s indicated airspeed decreases in relation to true airspeed as altitude increases. As the indicated airspeed decreases with

altitude, it progressively merges with the low speed buffet boundary where pre-stall buffet occurs for the airplane at a load factor of 1.0 G.

The point where the high speed Mach indicated airspeed and low speed buffet boundary indicated airspeed merge is the airplane’s

absolute or aerodynamic ceiling. This is where if an airplane flew any slower it would exceed its stalling AOA and experience low speed

buffet. Additionally, if it flew any faster it would exceed MMO, potentially leading to high speed buffet. This critical area of the airplane’s

flight envelope is known as ‘coffin corner.’ All airplanes are equipped with some form of stall warning system. Crews must be aware of

systems installed on their airplanes (stick pushers, stick shakers, audio alarms, etc.) and their intended function. In a high altitude

environment, airplane buffet is sometimes the initial indicator of problems.

50-Mach buffet occurs as a result of supersonic airflow on the wing. Stall buffet occurs at angles of attack that produce airflow disturbances

(burbling) over the upper surface of the wing which decreases lift. As density altitude increases, the AOA that is required to produce an

airflow disturbance over the top of the wing is reduced until the density altitude is reached where Mach buffet and stall buffet converge

(coffin corner). When this phenomenon is encountered, serious consequences may result causing loss of airplane control.

51-Increasing either gross weight or load factor (G factor) will increase the low speed buffet and decrease Mach buffet speeds. A typical jet

airplane flying at 51,000 feet altitude at 1.0 G may encounter Mach buffet slightly above the airplane’s MMO (0.82 Mach) and low speed

buffet at 0.60 Mach. However, only 1.4 G (an increase of only 0.4 G) may bring on buffet at the optimum speed of 0.73 Mach and any

change in airspeed, bank angle, or gust loading may reduce this straight-and-level flight 1.4 G protection to no protection at all.

Consequently, a maximum cruising flight altitude must be selected which will allow sufficient buffet margin for necessary maneuvering and

for gust conditions likely to be encountered. Therefore, it is important for pilots to be familiar with the use of charts showing cruise

maneuver and buffet limits.

52-The transitioning pilot must bear in mind that the maneuverability of the jet airplane is particularly critical, especially at the high altitudes.

Some jet airplanes have a narrow span between the high and low speed buffets. One airspeed that the pilot should have firmly fixed in

memory is the manufacturer’s recommended gust penetration speed for the particular make and model airplane. This speed is normally the

speed that would give the greatest margin between the high and low speed buffets, and may be considerably higher than design

maneuvering speed (VA). Pilots operating airplanes at high speeds must be adequately trained to operate them safely. This training cannot

be complete until pilots are thoroughly educated in the critical aspects of the aerodynamic factors pertinent to Mach flight at high altitudes.

LOW SPEED FLIGHT



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53-LOW SPEED FLIGHT The jet airplane wing, designed primarily for high speed flight, has relatively poor low speed characteristics. The

jet wing has less area relative to the airplane’s weight, a lower aspect ratio (long chord/short span), and thin airfoil shape—all of which

amount to the need for speed to generate enough lift. The sweptwing is additionally penalized at low speeds because its effective lift is

proportional to airflow speed that is perpendicular to the leading edge. This airflow speed is always less than the airspeed of the airplane

itself. In other words, the airflow on the sweptwing has the effect of persuading the wing into believing that it is flying slower than it actually

is.

54-The first real consequence of poor lift at low speeds is a high stall speed. The second consequence of poor lift at low speeds is the

manner in which lift and drag vary at those low speeds. As a jet airplane is slowed toward its minimum drag speed (VMD or L/D MAX), total

drag increases at a much greater rate than the changes in lift, resulting in a sinking flightpath. If the pilot attempts to increase lift by

increasing the AOA, airspeed will be further reduced resulting in a further increase in drag and sink rate as the airplane slides up the back

side of the power-required curve. The sink rate can be arrested in one of two ways: • Pitch attitude can be substantially reduced to reduce

the AOA and allow the airplane to accelerate to a speed above L/D MAX, where steady flight conditions can be reestablished. This

procedure, however, will invariably result in a substantial loss of altitude. • Thrust can be increased to accelerate the airplane to a speed

above L/D MAX to reestablish steady flight conditions. The amount of thrust must be sufficient to accelerate the airplane and regain altitude

lost. Also, if the airplane has slid a long way up the back side of the power required (drag) curve, drag will be very high and a very large

amount of thrust will be required. If continuous Mach decrease cannot be stopped after the maximum available thrust has been applied

during cruise, and if the Mach/airspeed indication can be considered reliable, flight crews should establish the airplane in a reasonable

descent to recover the initial targeted Mach. Contact ATC prior to beginning the descent if possible.

55-In a typical piston engine airplane, VMD in the clean configuration is normally at a speed of about 1.3 VS. Flight below L/D MAX on a

piston engine airplane is well identified and predictable. In contrast, in a jet airplane flight in the area of L/D MAX (typically 1.5 – 1.6 VS)

does not normally produce any noticeable changes in flying qualities other than a lack of speed stability—a condition where a decrease in

speed leads to an increase in drag which leads to a further decrease in speed and hence a speed divergence. A pilot who is not cognizant

of a developing speed divergence may find a serious sink rate developing at a constant power setting, and a pitch attitude that appears to

be normal. The fact that drag increases more rapidly than lift, causing a sinking flightpath, is one of the most important aspects of jet

airplane flying qualities

STALLS

56-STALLS The stalling characteristics of the sweptwing jet airplane can vary considerably from those of the normal straight wing airplane.

The greatest difference that will be noticeable to the pilot is the lift developed vs. angle of attack. An increase in angle of attack of the

straight wing produces a substantial and constantly increasing lift vector up to its maximum coefficient of lift, and soon thereafter flow

separation (stall) occurs with a rapid deterioration of lift.

57-By contrast, the sweptwing produces a much more gradual build-up of lift with a less well-defined maximum



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coefficient. This less-defined peak also means that a swept wing may not have as dramatic loss of lift at angles of attack beyond its

maximum lift coefficient. However, these high-lift conditions are accompanied by high drag, which results in a high rate of descent.

58-The differences in the stall characteristics between a conventional straight wing/low tailplane (non T-tail) airplane and a sweptwing T-tail

airplane center around two main areas. • The basic pitching tendency of the airplane at the stall. • Tail effectiveness in stall recovery.

59-On a conventional straight wing/low tailplane airplane, the weight of the airplane acts downwards forward of the lift acting upwards,

producing a need for a balancing force acting downwards from the tailplane. As speed is reduced by gentle up elevator deflection, the static

stability of the airplane causes a nose-down tendency. This is countered by further up elevator to keep the nose coming up and the speed

decreasing. As the pitch attitude increases, the low set tail is immersed in the wing wake, which is slightly turbulent, low energy air stall.

The conventional straight wing airplane conforms to the familiar nose-down pitching tendency at the stall and gives the entire airplane a

fairly pronounced nose down pitch. At the moment of stall, the wing wake passes more or less straight rearward and passes above the tail.

The tail is now immersed in high energy air where it experiences a sharp increase in positive AOA causing upward lift. This lift then assists

the nose-down pitch and decrease in wing AOA essential to stall recovery.

60-In a sweptwing jet with a T-tail and rear fuselage-mounted engines, the two qualities that are different from its straight wing low tailplane

counterpart are the pitching tendency The accompanying aerodynamic buffeting serves as a warning of impending stall. The reduced

effectiveness of the tail prevents the pilot from forcing the airplane into a deeper of the airplane as the stall develops and the loss of tail

effectiveness at the stall. The handling qualities down to the stall are much the same as the straight wing airplane except that the high, T-

tail remains clear of the wing wake and provides little or no warning in the form of a pre-stall buffet. Also, the tail is fully effective during the

speed reduction towards the stall, and remains effective even after the wing has begun to stall. This enables the pilot to drive the wing into

a deeper stall at a much greater AOA.

61-At the stall, two distinct things happen. After the stall, the sweptwing T-tail airplane tends to pitch up rather than down, and the T-tail can

become immersed in the wing wake, which is low energy turbulent air. This greatly reduces tail effectiveness and the airplane’s ability to

counter the nose up pitch. Also, if the AOA increases further, the disturbed, relatively slow air behind the wing may sweep across the tail at

such a large angle that the tail itself stalls. If this occurs, the pilot loses all pitch control and will be unable to lower the nose. The pitch up

just after the stall is worsened by large reduction in lift and a large increase in drag, which causes a rapidly increasing descent path, thus

compounding the rate of increase of the wing’s AOA.

62-A slight pitch up tendency after the stall is a characteristic of a swept or tapered wings. With these types of wings, there is a tendency

for the wing to develop a spanwise airflow towards the wingtip when the wing is at high angles of attack. This leads to a tendency for

separation of airflow, and the subsequent stall, to occur at the wingtips first.



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63-In an unmodified swept wing, the tips stall first, results in a shift of the center of lift of the wing in a forward direction relative to the center

of gravity of the airplane, causing a tendency for the nose to pitch up. A disadvantage of a tip first stall is that it can involve the ailerons and

erode roll control. To satisfy certification criteria, airplane manufacturers may have to tailor the airfoil characteristics of a wing as it proceeds

from the root to the tip so that a pilot can still maintain wings level flight with normal use of the controls. Still, more aileron will be required

near stall to correct roll excursion than in normal flight, as the effectiveness of the ailerons will be reduced and feel mushy. This change in

feel can be an important recognition cue that the airplane may be stalled.

64-As previously stated, when flying at a speed near L/D MAX, an increase in AOA causes drag to increase faster than lift and the airplane

begins to sink. It is essential to understand that this increasing sinking tendency, at a constant pitch attitude, results in a rapid increase in

AOA as the flightpath becomes deflected downwards. Furthermore, once the stall has developed and a large amount of lift has been lost,

the airplane will begin to sink rapidly and this will be accompanied by a corresponding rapid increase in AOA. This is the beginning of what

is termed a deep stall.

65-As an airplane enters a deep stall, increasing drag reduces forward speed to well below normal stall speed. The sink rate may increase

to many thousands of feet per minute. It must be emphasized that this situation can occur without an excessively nose-high pitch attitude.

On some airplanes, it can occur at an apparently normal pitch attitude, and it is this quality that can mislead the pilot because it appears

similar to the beginning of a normal stall recovery. It can also occur at a negative pitch attitude, that is, with the nose pointing towards the

ground. In such situations, it seems counterintuitive to apply the correct recovery action, which is to push forward on the pitch control to

reduce the AOA, as this action will also cause the nose to point even further towards the ground. But, that is the right thing to do.

66-Deep stalls may be unrecoverable. Fortunately, they are easily avoided as long as published limitations are observed. On those

airplanes susceptible to deep stalls (not all swept or tapered wing airplanes are), sophisticated stall warning systems such as stick shakers

are standard equipment. A stick pusher, as its name implies, acts to automatically reduce the airplane’s AOA before the airplane reaches a

dangerous stall condition, or it may aid in recovering the airplane from a stall if an airplane’s natural aerodynamic characteristics do so

weakly.

67-Pilots undergoing training in jet airplanes are taught to recover at the first sign of an impending stall instead of going beyond those initial

cues and into a full stall. Normally, this is indicated by aural stall warning devices or activation of the airplane’s stick shaker. Stick shakers

normally activate around 107 percent of the actual stall speed. In response to a stall warning, the proper action is for the pilot to apply a

nose-down input until the stall warning stops (pitch trim may be necessary). Then, the wings are rolled level, followed by adjusting thrust to

return to normal flight. The elapsed time will be small between these actions, particularly at low altitude where a significant available thrust

exists. It is important to understand that reducing AOA eliminates the stall, but applying thrust will allow the descent to be stopped once the

wing is flying again.

68-At high altitudes the stall recovery technique is the same. A pilot will need to reduce the AOA by lowering the nose



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until the stall warning stops. However, after the AOA has been reduced to where the wing is again developing efficient lift, the airplane will

still likely need to accelerate to a desired airspeed. At high altitudes where the available thrust is significantly less than at lower altitudes,

the only way to achieve that acceleration is to pitch the nose downwards and use gravity. As such, several thousand feet or more of altitude

loss may be needed to recover completely. The above discussion covers most airplanes; however, the stall recovery procedures for a

particular make and model airplane may differ slightly, as recommended by the manufacturer, and are contained in an approved Airplane

Flight Manual for that airplane.

69-Drag Devices To the pilot transitioning into jet airplanes, going faster is seldom a problem. It is getting the airplane to slow down that

seems to cause the most difficulty. This is because of the extremely clean aerodynamic design and fast momentum of the jet airplane and

because the jet lacks the propeller drag effects that the pilot has been accustomed to. Additionally, even with the power reduced to flight

idle, the jet engine still produces thrust, and deceleration of the jet airplane is a slow process. Jet airplanes have a glide performance that is

double that of piston-powered airplanes, and jet pilots often cannot comply with an ATC request to go down and slow down at the same

time. Therefore, jet airplanes are equipped with drag devices, such as spoilers and speed brakes.

70-The primary purpose of spoilers is to spoil lift. The most common type of spoiler consists of one or more rectangular plates that lie flush

with the upper surface of each wing. They are installed approximately parallel to the lateral axis of the airplane and are hinged along the

leading edges. When deployed, spoilers deflect up against the relative wind, which interferes with the flow of air about the wing. This both

spoils lift and increases drag. Spoilers are usually installed forward of the flaps but not in front of the ailerons so as not to interfere with roll

control.

71-Deploying spoilers results in a substantial sink rate with little decay in airspeed. Some airplanes exhibit a nose-up pitch tendency when

the spoilers are deployed, which the pilot must anticipate.

72-When spoilers are deployed on landing, most of the wing’s lift is destroyed. This action transfers the airplane’s weight to the landing

gear so that the wheel brakes are more effective. Another beneficial effect of deploying spoilers on landing is that they create considerable

drag, adding to the overall aerodynamic braking. The real value of spoilers on landing, however, is creating the best circumstances for

using wheel brakes.

73-The primary purpose of speed brakes is to produce drag. Speed brakes are found in many sizes, shapes, and locations on different

airplanes, but they all have the same purpose—to assist in rapid deceleration. The speed brake consists of a hydraulically-operated board

that, when deployed, extends into the airstream. Deploying speed brakes results in a rapid decrease in airspeed. Typically, speed brakes

can be deployed at any time during flight in order to help control airspeed, but they are most often used only when a rapid deceleration

must be accomplished to slow down to landing gear and flap speeds. There is usually a certain amount of noise and buffeting associated

with the use of speed brakes, along with an obvious penalty in fuel consumption. Procedures for the use of spoilers and/or speed brakes in

various situations are contained in an approved AFM for the particular airplane.



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CAUSES OF UPSET CONDITIONS

74-CAUSES OF UPSET CONDITIONS There are many different causes of upset conditions that can singularly put an aircraft in a

dangerous situation or can combine to cause a hazardous situation. The basic causes we will discuss are: * Environmentally induced upset

* Upset from systems-anomalies * Pilot induced causes * A combination of two or more of the above

Environmentally Induced Upset

75-ENVIRONMENTALLY INDUCED UPSET Environmental conditions such as turbulence, windshear, thunderstorms, microbursts, wake

turbulence and aircraft icing can cause an aircraft upset. Of course, the severity of the upset is directly proportional to the severity of the

environmental condition that is encountered and the ability of the pilots to recognize the threat and take proper, timely recovery techniques.

76-Turbulence is characterized by large variations in speed and direction of the relative wind the aircraft it passing through. There are

different types and degrees of turbulence. Turbulence can be caused by convective activity around thunderstorms or frontal passage.

Crossing a jet stream or area of windshear can cause it. Turbulence can be found without convective activity in what is known as Clear Air

Turbulence (CAT). This is generally found above 15,000 ft. and near jet streams. This form of turbulence can be very unpredictable and

can surprise pilots and passengers with the magnitude of deviation from stabilized flight. CAT causes many injuries annually, especially to

passengers and crewmember not seated with their seatbelts secure. The level of this type of turbulence can range from light to severe.

Aircraft control can be in doubt in severe conditions.

77-Mountain wave turbulence can be found on the leeward side of mountain ranges. This form of turbulence can be found from the ground

level to above 30,000 ft. It is generally associated with perpendicular wind components exceeding 50 kts. Mountain wave effect can

sometimes be identified by the presence of rotor or lenticular clouds over the mountaintops. The level of this type of turbulence can also

range from light to severe.

78-Windshear is a variation in the direction and speed of the relative wind. This mechanical change can cause a very unstable condition

which can challenges aircraft control. Airspeed can increase or decrease sharply when passing through a shear. The aircraft can also be

subject to updrafts or downdrafts, which can cause dramatic, roll or pitch deviations. This combination can cause an out of control situation

very close to the ground. These variations in the speed and direction of the wind can be caused by: the topography, temperature

inversions, strong surface winds and convective activity like thunderstorms or frontal passage.

79-Thunderstorms can cause huge changes is surface wind direction and downdrafts which cause windshear and microbursts. These

conditions can occur from the surface to over 80,000 ft. Due to the magnitude of energy contained in a thunderstorm, it is very important

that crews use extreme caution to avoid the effects of thunderstorms at all altitudes.

80-Microbursts are generally associated with thunderstorms or other convective activity. Microbursts are very strong downdrafts, which can

cause a dangerous situation for aircraft near the ground. Immediate detection and proper recovery



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procedures are necessary to assure a safe recovery. Microbursts can also cause a very dramatic change in airspeed in the form of a

quickly changing headwind or tailwind. It is important to recognize that recovery from some microburst encounters may not be successful

with any technique. The crew must be aware of the severity of their situation and take proper action. Some of the fatal accidents that have

occurred to date could have avoided with proper training, crews correctly recognizing their condition and correctly applying recovery

techniques in a timely manner.

81-Wake turbulence is manifested in the form of vortices from aircraft wings. The strongest and most dangerous conditions are during

takeoff and landing, when the aircraft are fully configured. These vortices can last 30 seconds to 5 minutes depending on the weight and

size of the aircraft and the prevailing wind conditions. Aircraft departing or arriving after large aircraft need to take precautions to avoid this

situation. Wake turbulence has caused many upset conditions and a few fatal mishaps. Wake turbulence can also upset a smaller aircraft

when a larger aircraft overtakes it from above its assigned flight level. The wake turbulence can fall at a rate from 200-500 fpm. In RVSM

airspace the smaller aircraft can be only 1000 ft. below the larger aircraft. Severe upsets have been recorded in this situation in addition to

events close to the runway.

82-Aircraft icing both on the ground and airborne have caused many upset conditions. It is very important that all ice and frost be removed

from the aircraft prior to takeoff. Even as little as 1/16 of an inch of ice can contaminate the wing/aircraft surface and adversely affect the

aerodynamic capability of the wing to create lift. The added weight of the ice can also add to a possible upset condition. Ice build-up in flight

can cause the same adverse conditions. Caution should be used flying in freezing temperatures in areas of know icing or moisture.

System Anomalies Induced Upsets

83-SYSTEM ANOMALIES INDUCED UPSETS Modern aircraft have many systems intended to make flight operations easier and safer.

Systems can fail and pilots can build an over reliance on these devices, which both can lead to an aircraft upset.

84-Despite modern airplane design, specialized training and improved reliability, system failures still occur which can lead to an upset

condition. Most of these conditions are survivable with the proper recognition and recovery technique. The major systems we will discuss

are flight instrument, autoflight systems, and flight control anomalies.

85-Flight instruments failures are infrequent but they still do occur. Current training is available to prepare crews to use the normal and

abnormal procedures found in aircraft flight manuals. They teach the pilot how to identify and react to these failures. Aircraft certifications

require the knowledge and systems required to react to these failures. Most mishaps are caused by the failure of the pilots to identify the

problem in a timely manner and then to take appropriate corrective actions before the aircraft upset can reach hazardous level.

86-Autoflight systems like the autopilot, autothrottles and related systems which make up the Flight Management System gather

information from many different sensors and programmed data to calculate navigational and performance status of the aircraft. Each

system has certain limitations built into the units, which may not always be apparent to the pilots.



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The systems may fail or have some form of abnormal operation, which may result in an aircraft upset.

87-Flight control anomalies are usually caused by flap asymmetry, spoiler problems, inadvertent rudder inputs or other flight control

problems. Aircraft flight manuals and training cover these anomalies and the required corrective action. If the condition is not correctly

identified or the response is incorrectly applied, the aircraft could be placed into an upset condition. During critical phases of flight, like

takeoff and landing, these conditions could lead to an accident.

88-During extended use of the autopilot/autothrottles the systems can ‘trim’ the aircraft to the limits of the automated systems capability to

maintain itself within the normal flight envelope; then once the limits have been exceeded, the autopilot can unexpectedly release

presenting the pilots with a nose-up or nose-low condition and in an ‘out of trim’ condition.

89-Pilots must carefully monitor the status of aircraft systems to avoid this situation this is called active monitoring. Active monitoring is

defined as a proactive knowledge-driven process of encountering and keeping track of how things are in relation to the perceiver and his

expectations to enable the perceiver to take meaningful action. Active monitoring involves proactively seeking relevant information, making

important information available, filtering information that is meaningless, creating new information, and off-loading cognitive processing onto

the interface or adapting the interface to support monitoring’.

90-Effective monitoring of the environment, the airplane energy state and flight path depends very heavily on an accurate and

comprehensive understanding of the current airplane's energy state and flight path trajectory based on the relevant indications of its status.

This understanding, or mental model, can then be used to create expectations about future state and deviations from the expected state.

These expectations then serve as a baseline for monitoring.

91-The monitoring process involves: Pilots using their knowledge to formulate an understanding (mental model). Their understanding

(mental model) is used to create a set of expectations that directs their attention and their perception of events, e.g. if you are expecting to

level off you are likely to monitor parameters associated with level off. When their expectations are not met, pilots use their knowledge to

direct their attention to seek and perceive additional information to fill any gaps in their understanding that were identified by the deviations.

Actively seeking more information is part of the monitoring process leading to corrective actions if necessary. Monitoring other parameters,

changing the display information, and communicating with the other crew members are ways to get more information.

Pilot Induced Upsets

92-PILOT INDUCED UPSETS Modern aircraft have more reliable systems than in the past, however pilots are still susceptible to false

sensory inputs and misidentification of aircraft anomalies. At night or IMC, pilots can misunderstand the actual position and attitude of their

aircraft. To help with this problem, aircraft have been equipped with flight instrument, autoflight systems and accurate warning systems to

inform the crew of a deteriorating situation.

93-The major causes of pilot induced upset events are: poor instrument cross-check, inattention and distraction from



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primary cockpit duties, vertigo, and improper use of aircraft automation. Pilots can also improperly analyse symptoms and indications of an

abnormal state.

94-Instrument cross-check is the basic procedure for pilots flying in IMC or night conditions to monitor the flight performance of the aircraft.

A slow cross-check can lead to an unstable condition which could lead to an upset. As pilots, have moved on to modern aircraft with glass

cockpit instruments they found many of the familiar individual instruments had been combined into one or two centrally located instrument.

This generally makes the cross-check easier but can cause confusion due to many different changing bits of information in a confined

place. A return to older version aircraft with individual instruments can be a major challenge after using the modern glass cockpits. If

systems do fail, a good cross-check is essential to identification and recovery from a usable condition.

95-Inattention or distraction from primary cockpit duties can lead to large deviations in aircraft attitude, speed or location. Distractions can

be as subtle as a radio call, excessive use of automation, abnormal condition or just complacency. The priorities while flying are always to

aviate, navigate, communicate. Unfortunately, pilots sometimes perform these priorities out of order. Upset conditions usually occur when

lower priority issue distracts pilots.

96-Vertigo or Spatial Disorientation has been a significant factor in upset mishaps. All humans are susceptible to sensory illusions

especially when in IMC, in night conditions and the horizon is not in sight. It is essential that the pilot adjust their orientation to the correct

reference by use of flight instrument and a proper cross-check.

97-Dependency on or improper use of automation can lead to an upset condition. When automation is properly used, it adds to flight safety

and situation awareness of the crews. Unfortunately, crews have become complacent due to the increased use of automated system. In

some cases, the automation can fly the aircraft better than most pilots and the pilots then trust the automation in all situations. Automation

cannot determine when the aircraft is in danger and the proper recovery procedure to use. Automation will do what the pilots tell it to do.

Pilots must be proficient at all levels of automation so they can properly respond to changes. In an escape situation, such as GPWS,

EGPWS, TCAS RA and other situations where immediate direct control of the aircraft is demanded, automation should be turned off and

the aircraft manual flown until restored to a safe condition. Limitations in autopilot and autothrottle systems can lead to an unstable

condition. Pilot’s failure to monitor aircraft system and status on a frequent basis can lead to upset conditions.

Combination Of Cause Factors

98-COMBINATION OF CAUSE FACTORS Usually these types of upsets are initially started by one of the events we have already

discussed. Then another factor like pilot induced error aggravates the recovery. As we have discussed, one of the keys to a successful

recovery is first correctly identifying the original cause of the upset. Sometimes automation or an environmental condition can make it

difficult for pilots to analyse the actual cause of the event, therefore pilots can attempt the wrong recovery technique resulting in a late

recovery or a mishap. It is important that pilots disconnect all automation (autopilot/autothrottles) so they are not being confused by

automation inputs.

Aerodynamic Factors Leading To Upset Conditions



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99-AERODYNAMIC FACTORS LEADING TO UPSET CONDITIONS Modern transport/corporate category aircraft have certain

aerodynamic features that can lead to an upset condition. Pilots must be familiar with factors such as; swept-wing airplane fundaments,

flight dynamics, energy state, load factors, the aircraft flight envelope, angle of attack/stall conditions, wing dihedral effects, pilot

commanded sideslip, high airspeed/high altitude characteristics, stability, maneuver in pitch, roll, yaw, and flight at very high and low

speeds.

100-The aerodynamic flight envelope of modern aircraft set the boundaries for the safe operation of the aircraft and pilots must be familiar

with the limits of their aircraft to avoid a possible upset condition. Current jet transport/corporate airplanes are certificated to withstand

normal vertical load factors from -1.0 to 2.5 g in the cruise configuration. In addition to the strength of the structure, the handling qualities

are demonstrated to be safe within these limits of load factors. The pilot should be able to maneuver safely to and from these load factors

at these speeds, without needing exceptional strength or skills. Test pilots have evaluated the characteristics of airplanes in conditions that

include inadvertent deviations of these operational envelopes to demonstrate that the airplanes can be returned safely to the operational

envelopes. It is important that pilots know and protect the aircraft from exceeding the limits of the flight envelope.

101-Swept-wing aircraft fundaments require a discussion of: flight dynamics, energy states, load factors, the flight envelope and basic

aerodynamics.

102-Flight dynamics in a discussion of the effects of swept-wing transport/corporate airplanes, it is important to first understand what

causes the forces and movements acting on the airplane and then move to what kinds of motion these forces cause. With this background,

we can gain an understanding of how a pilot can control these forces and moments to direct the flight path. The generation of the forces is

the subject of aerodynamics (to be discussed later). The generation of forces requires energy, which for discussion purposes can be called

‘energy state.’

103-The term ‘energy state’ describes how much of each kind of energy the airplane has available at any given time. Pilots who understand

the airplane energy state will be able to know instantly what options they may have to maneuver their airplane.

104-The three sources of energy available to the pilot are 1. Kinetic energy, or energy in action, which increases with increasing airspeed.

2. Potential energy, or stored energy, which is approximately proportional to altitude. 3. Chemical energy, from the fuel in the tanks.

105-During maneuvering, these three types of energy can be traded, or exchanged, usually at the cost of additional drag. The relationships

are shown here: * Airspeed can be traded for altitude, and altitude can be traded for airspeed. * Stored energy can be traded for either

altitude or airspeed.

106-Modern high-performance, jet airplanes have low drag characteristics in cruise configuration; therefore, the pilot needs to exercise

considerable caution in making very large energy trades. A clean airplane operating near its limits can



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easily go from the low-speed boundary to and through the high-speed boundary very quickly. It is essential that the pilots know the limits of

the flight envelope on both the high and low speed side. The process of controlling forces to change accelerations and produce a new

energy state takes time. The longer time required by large airplanes requires that the pilot to plan ahead. The objective is to manage

energy so that total energy state remains within the flight envelope. Once the aircraft approaches the edge of the flight envelope greater

forces are required to return it to a normal energy state.

107-Flight at very slow speeds, close to the edge of the flight envelope can be very hazardous. It is possible for the airplane to be flown at

speeds below the defined stall speed. This regime is outside the flight envelope. At extremely low airspeed, there are several important

effects for the pilot to know about. Lift generated by wings and tails depends on both the angle of attack and the velocity of the air moving

over the surfaces. At very low airspeeds, an aircraft wing surface will produce lift. The lift generated may not be enough to support the

weight of the airplane. In the case of the lift generated by the tail, at very low airspeed, it may not be great enough to trim the airplane, that

is, to keep it from pitching. It may be difficult to command a change in attitude until gravity produces enough airspeed to generate sufficient

lift that is only possible at angles of attack below the stall angle. For this reason, if airspeed is decreasing rapidly, it is very important to

reduce angle of attack and use whatever aerodynamic forces are available to orient the airplane so that a recovery may be made when

sufficient forces are available.

108-The situation becomes only slightly more complicated when thrust is considered. In aircraft with engines offset from the center of

gravity, thrust produces both forces and moments. As airspeed decreases, engine thrust generally increases for a given throttle setting.

With engines below the center of gravity, there will be a nose-up moment generated by engine thrust. Especially at high power settings, this

may contribute to even higher nose-up attitudes and even lower airspeeds. Pilots should be aware that, as aerodynamic control

effectiveness diminishes with lower airspeeds, the forces and moments available from thrust become more evident, and until the

aerodynamic control surfaces become effective, the trajectory will depend largely on inertia and thrust effects.

109-In aircraft with centerline thrust, most corporate aircraft, this factor is reduced so there is less rolling moment. Great caution should be

used so that the pilots do not allow the aircraft to reach an energy state in which the aircraft is ‘behind the thrust curve’. At a specific

attitude, g-factor and airspeed, increasing thrust will not arrest a descent. The aircraft can only be recovered by lowering the nose to

increase airspeed to return the aircraft into the flight envelope.

110-Flight at extremely high speeds can also be very hazardous to aircrews. Inadvertent excursions into extremely high speed, either Mach

or airspeed, should be treated very seriously. Flight at very high Mach numbers puts the airplane in a region of reduced maneuvering

envelope. Pilots need to be aware that the envelope is small. Prudent corrective action is necessary to avoid exceeding limits at the other

end of the envelope, should an inadvertent excursion occur. Flight in the high-airspeed regime brings with it an additional consideration of

very high control power. At speeds, higher than maneuver speed, very large deflection of the controls has the potential to generate

structural damage or failure. In either the Mach or airspeed regime, if speed is excessive, the first priority should be to reduce speed to

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structural limits of the aircraft. This can happen in cruise operation but also occur in a high-speed dive, which could occur due to another

type of upset or maneuver. Pilots must use throttles and speed brakes as necessary to avoid exceeding critical airspeed limits.

111-Load Factors: A change in either magnitude or direction of the velocity of the aircraft is considered acceleration. Acceleration is

described in terms of gravity, or simply, g’s. The load factor expressed in g’s is typically discussed in terms of components relative to the

principal axes of the airplane: longitudinal, lateral and vertical. In level flight, the vertical load factor is 1g. Acceleration is a result of the sum

of all forces acting on the airplane. One of these forces is always gravity, and gravity always produces an acceleration vector directed

toward the center of the Earth

112-Angle of Attack and Stall: Wing and tail surfaces all produce lift forces. The lift force is created by the angle of attack and the relative

wind crossing the camber of the wing. As angle of attack is increased, lift increases proportionally up to the point where the air starts to

separate from the wing. At the critical angle of attack, the airflow separates from the wing and the surface is stalled. This is true regardless

of airplane speed or altitude. Angle of attack can sometimes be confusing. Angle of attack is always the angle between the oncoming air or

relative wind, and some reference line on the airplane or wing. Sometimes it is referenced to the chord line at a particular location on the

wing. Exceed the critical angle of attack on the lifting surfaces it will result in a loss of lift on those surfaces. The aircraft can stall at any

attitude or airspeed if the critical angle of attack is exceeded. Once the critical angle of attack is exceeded the lifting surfaces are no longer

producing lift. A stall is characterized by any of the following, or a combination, of the following: buffeting, loss of pitch authority, loss of roll

control and a loss of ability to stop the descent rate. The flight manual has stall speeds for different configurations and weights but those

numbers can change for conditions exceeding normal operations. The critical angle of attack is reduced at high Mach numbers.

113-Lateral and Directional Aerodynamic Considerations: The static lateral stability of an airplane involves consideration of rolling moments

due to sideslip. The forces and moments generated by the sideslip can affect motion in all three axes of the airplane.

114-Wing Dihedral Effects: Dihedral is the positive angle formed between the lateral axis of an airplane and a line that passes through the

center of the wing. Although dihedral contributes to the lateral stability of an airplane, each time the aircraft roles the dihedral does cause

some sideslip moment. A wing with dihedral will develop stable rolling moments with sideslip. Wing sweep is beneficial for high-speed flight

because it will delay compressibility effects. A sideslip on a swept-wing airplane results in a larger rolling moment than on a straight-wing

airplane. Rudder input produces sideslip and contributes to the dihedral effect. At high angles of attack, aileron and spoiler controls become

less effective. The rudder is still effective and can assist in certain recoveries, in low speed, high angle of attack situations but still must be

used only as necessary to recover from an upset condition.

115-Pilot-Commanded Sideslip: The rudders on modern transport jets are sized to counter the yawing moment associated with engine

failure at very low takeoff speeds. It is important to realize that these powerful rudder inputs are available



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whether or not an engine has failed. Large rolling moments are possible through the rudder, which can lead to an upset condition.

RECOVERY FROM AIRPLANE UPSETS

116-RECOVERY FROM AIRPLANE UPSETS Recovery from an upset condition requires that the pilots recognize the condition, correctly

analyse the actual situation and then correctly apply the desired recovery procedure in a timely manner. Guard against allowing the

recovery from one upset create a different upset situation.

117-The pilots can become startled by an upset condition since they happen very infrequently. The tendency of the many pilots is to react

before they have time to analyse the symptoms DO NOT REACT WITHOUT ANALYSING THE CONDITION of the upset or fixate on one

indication leading to an incorrect analysis of the situation. Pilots must remember to: maintain the status quo (don’t aggravate the condition),

analyse the situation (look for confirming information from primary flight instruments and the energy state), and then take proper action.

118-Simulator training can prepare the pilot for procedures to take during the recovery but will not help them recognize and analyse the

situation.

119-Flight control forces become less effective when the airplane is at or near its critical angle of attack or stall. The tendency is for pilots

not to use full control authority or use full throttle because they rarely are required to do so.

120-Upset conditions, caused by rudder deflection, can be recognized by large bank angles and the nose rapidly falling below the horizon.

The rudder should not normally be used to induce roll through sideslip because transient sideslip can induce very rapid roll rates with

significant time delay. The combination of rapid roll rates and the delay can startle the pilot, which in turn can cause the pilot to overreact in

the opposite direction. The overreaction can induce abrupt yawing movements and violent out-of-phase roll rates, which can lead to

successive cyclic rudder deflections, known as rudder reversals. Rapid full-deflection flight control reversals can lead to loads that can

exceed structural design limits.

121-An overview of actions to recover from an upset would encompass three basic activities: 1. Assess the energy (become situationally

aware) 2. Arrest the flight path divergence 3. Recover to a stabilized flight path These three activities must be part of every recovery from

an upset.

122-A pilot actively monitoring is an engaged pilot who has a wealth of information available to them in modern cockpits. Consequently,

they are more situationally aware than all previous generations of pilots. An engaged pilot will be ready to intercept an unintentional

airplane divergence which is the overwhelming goal: avoid an upset from developing in the first place. The first actions for recovering from

an airplane upset must be correct and timely.

123-It is very important for the crew to realize the differences in airplane handling at high altitude, versus low altitude (less thrust/power

available and more sensitive flight controls). Managing startle is imperative all the time, but particularly in high altitude conditions where the

pilot has the least amount of hands on experience to manipulate the airplane. The



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key point is to use gentle control inputs and not arbitrary open loop inputs. Exaggerated control inputs through reflex responses must be

avoided. An excessive or inappropriate control input that overshoots the desired response can startle the pilot and cause one upset to lead

to another.

124-Visual meteorological conditions may allow the use of references outside the airplane; however, it can be difficult to see the horizon if

the field of view is restricted due to window geometry and overhead panel placement during both high and low pitch attitudes.

125-It is necessary to use the primary flight instruments and the airplane performance instruments when analysing the upset situation.

Pilots must be prepared to analyse the situation during darkness and when instrument meteorological conditions (IMC) exist. The PFD or

Attitude Indicator is a primary reference for recovery.

126-For a nose-low upset, normally the airspeed is increasing, altitude is decreasing and the vertical speed indicator (VSI) indicates a

descent.

127-For a nose-high upset, the airspeed normally is decreasing, altitude is increasing and the VSI indicates a climb.

128-Other attitude sources must be cross checked for accuracy of interpretation of the situation. These sources include, but are not limited

to the Standby Attitude Indicator and the pilot monitoring (PM) instruments. Pitch attitude is determined from the PFD or Attitude Indicator

pitch reference scales. Most modern displays also use colors (blue for sky, brown for ground) or ground perspective lines to assist in

determining whether the airplane pitch is above or below the horizon. Even in extreme attitudes, some portion of the sky or ground

indications is usually present to assist the pilot in analysing the situation. The bank indicator on the PFD/Attitude Indicator should be used

to determine the airplane bank.

129-The situation analysis process is to: Assess the energy Confirm the airplane attitude (pitch and bank angle) Communicate with the

other crew member(s). Recovery techniques presented later in this section include the phrase, ‘Recognize and confirm the situation’. This

situation analysis process is used to accomplish that technique.

130-The physical and psychological effects and the airplane response during recovery can be significantly different from that experienced

during simulator training. Simulator limitations at the edges of the flight envelope can also cause fidelity issues because the simulator

recovery may not have the same response characteristics as the airplane. However, provided the simulator valid training envelope limits

are not exceeded, the control loading responses and instrument indications of the simulator should accurately replicate airplane responses.

131-Pilots must avoid reacting before analysing what is happening and avoid fixating on one indication instead of diagnosing the situation.

Effective training and crew engagement (active monitoring) during all cockpit activity is the best insurance to deal with startle factor.

132-Pilots are normally uncomfortable with unloading g forces to less than 1 g on passenger airplanes. They must overcome this

reluctance if faced with a situation that requires unloading the airplane to less than 1 g by pushing forward



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on the pitch controls. While flight simulators can replicate normal flight profiles, they cannot replicate sustained g forces, other than 1 g.

Pilots must anticipate a significantly different feeling in flight during less than 1 g situations.

133-Utilizing up to full flight control inputs is not a part of routine airline flying. Pilots must be prepared to use full flight control authority if the

situation warrants it. Flight control inputs are more effective at increased speed/reduced angle of attack. Conversely, at low airspeeds or

approaching the critical angle of attack, larger control inputs are needed for the same airplane response. Attitude and flight path changes

can be very rapid during an upset, which could require large or even full scale control inputs

134-Warning: There are NO situations that will require rapid full-scale control deflections from one side to the other. This can cause

structural failure of aircraft control surfaces!

135-Upset recovery techniques can be refined into either: * Nose high * Nose low.

136-This provides the basis for relating the aerodynamic information and techniques to specific situations. Consolidation of recovery

techniques into these two situations is done for simplification and ease of retention. Airplanes with electronic flight control systems (fly-by-

wire, FBW), have features that should minimize the possibility of an upset and assist the pilot in recovery, if it becomes necessary. When

FBW airplanes are in a degraded flight control mode, the recovery techniques and aerodynamic principles discussed in this training aid are

appropriate. Principles of recognition and recovery techniques still apply independent of flight control architecture.

137-Autopilots (A/P) and autothrottles (A/THR) are generally intended to be used when the airplane is within its normal flight envelope. If

the A/P and/or A/THR are responding correctly to a flight path and/or energy divergence, it may not be appropriate to decrease the level of

automation. Adhere to OEM guidance. If the A/P and A/THR are not responding correctly, they must be disconnected.

138-Analysis of the energy state of the airplane is required. This analysis assesses the energy and trend. This includes but is not limited to

altitude, airspeed, attitude, load factor, power setting, position of flight controls, position of drag and high-lift devices and the rate of change

of those conditions. This analysis should allow the crew to make appropriate changes, such as use of speed brakes or lowering the landing

gear for drag as necessary to aid in the recovery. In other words, manage the energy.

Stallrecovery.

139-STALL RECOVERY. In all upset situations, it is necessary to recover from a stall before applying any other recovery actions. To

recover from the stall, angle of attack must be reduced below the stalling angle. Nose-down pitch control must be applied and maintained

until the wings are unstalled. Under certain conditions, on airplanes with underwing-mounted engines, it may be necessary to reduce some

thrust in order to prevent the angle of attack from continuing to increase. Once unstalled, upset recovery actions may be taken and thrust

reapplied as needed.

Nose High, Wings Level.



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140-NOSE HIGH, WINGS LEVEL. In a situation where the airplane pitch attitude is unintentionally more than 25 degrees nose high and

increasing, the kinetic energy (airspeed) is decreasing rapidly. Per the energy management discussed earlier, the energy is being stored as

potential energy. As airspeed decreases, the pilot's ability to maneuver the airplane also decreases. If the stabilizer trim setting is nose up,

as for slow-speed flight, it partially reduces the nose-down authority of the elevator. Further complicating this situation, as the airspeed

decreases, the pilot could intuitively make a large thrust increase. This will cause an additional pitch up for underwing-mounted engines. At

full thrust settings and very low airspeeds, the elevator -- working in opposition to the stabilizer -- will have limited control to reduce the pitch

attitude.

141-In this situation, the pilot should trade the potential energy of altitude for airspeed, and would have to maneuver the airplane's flight

path back toward the horizon. This is accomplished by the input of up to full nose-down elevator and the use of some nose-down stabilizer

trim. These actions should provide sufficient elevator control power to produce a nose-down pitch rate. It may be difficult to know how much

stabilizer trim to use, and care must be taken to avoid using too much trim. Pilots should not fly the airplane using stabilizer trim, and should

stop trimming nose down when they feel the g force on the airplane lessen or the required elevator force lessen. This use of stabilizer trim

may correct an out-of-trim airplane and solve a less-critical problem before the pilot must apply further recovery measures. Because a large

nose-down pitch rate will result in a condition of less than 1 g, at this point the pitch rate should be controlled by modifying control inputs to

maintain between 0 to 1 g. If altitude permits, flight tests have determined that an effective way to achieve a nose-down pitch rate is to

reduce some thrust on airplanes with underwing-mounted engines. The use of this technique is not intuitive and must be considered by

each operator for their specific fleet types.

142-If normal pitch control inputs do not stop an increasing pitch rate, rolling the airplane to a bank angle that starts the nose down should

work. Bank angles of about 45 degrees, up to a maximum of 60 degrees, could be needed. Unloading the wing by maintaining continuous

nose-down elevator pressure will keep the wing angle of attack as low as possible, making the normal roll controls as effective as possible.

With airspeed, as low as stick shaker onset, normal roll controls -- up to full deflection of ailerons and spoilers -- may be used. The rolling

maneuver changes the pitch rate into a turning maneuver, allowing the pitch to decrease. Finally, if normal pitch control then roll control is

ineffective, careful rudder input in the direction of the desired roll may be required to induce a rolling maneuver for recovery. Only a small

amount of rudder is needed. Too much rudder applied too quickly or held too long may result in loss of lateral and directional control.

Because of the low energy condition, pilots should exercise caution when applying rudder. The reduced pitch attitude will allow airspeed to

increase, thereby improving elevator and aileron control effectiveness. After the pitch attitude and airspeed return to a desired range the

pilot can reduce angle of bank with normal lateral flight controls and return the airplane to normal flight.

Nose Low, Wings Level.

143-NOSE LOW, WINGS LEVEL. In a situation where the airplane pitch attitude is unintentionally more than 10 degrees nose low and

going lower, the kinetic energy (airspeed) is increasing rapidly. A pilot would likely reduce thrust and extend



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the speed brakes. The thrust reduction will cause an additional nose-down pitching moment. The speed brake extension will cause a nose-

up pitching moment, an increase in drag, and a decrease in lift for the same angle of attack. At airspeeds, well above VMO/MMO, the ability

to command a nose-up pitch rate with elevator may be reduced because of the extreme aero-dynamic loads on the elevator.

144-Again, it is necessary to maneuver the airplane's flight path back toward the horizon. At moderate pitch attitudes, applying nose-up

elevator -- and reducing thrust and extending speed brakes, if necessary -- will change the pitch attitude to a desired range. At extremely

low pitch attitudes and high airspeeds (well above VMO/MMO), nose-up elevator and nose-up trim may be required to establish a nose-up

pitch rate.

145-HIGH BANK ANGLES. A high bank angle is one beyond that necessary for normal flight. Though the bank angle for an upset has been

defined as unintentionally more than 45 degrees, it is possible to experience bank angles greater than 90 degrees.

146-Any time the airplane is not in ‘zero-angle-of-bank’ flight, lift created by the wings is not being fully applied against gravity, and more

than 1 g will be required for level flight. At bank angles greater than 67 degrees, level flight cannot be maintained within flight manual limits

for a 2.5 g load factor. In high bank angle increasing airspeed situations, the primary objective is to maneuver the lift of the airplane to

directly oppose the force of gravity by rolling to wings level. Applying nose-up elevator at bank angles above 60 degrees causes no

appreciable change in pitch attitude and may exceed normal structure load limits as well as the wing angle of attack for stall. The closer the

lift vector is to vertical (wings level), the more effective the applied g is in recovering the airplane. A smooth application of up to full lateral

control should provide enough roll control power to establish a very positive recovery roll rate. If full roll control application is not

satisfactory, it may even be necessary to apply some rudder in the direction of the desired roll. Only a small amount of rudder is needed.

Too much rudder applied too quickly or held too long may result in loss of lateral and directional control or structural failure.

147-NOSE HIGH, HIGH BANK ANGLES. A nose-high, high-angle-of-bank upset requires deliberate flight control inputs. A large bank angle

is helpful in reducing excessively high pitch attitudes. The pilot must apply nose-down elevator and adjust the bank angle to achieve the

desired rate of pitch reduction while considering energy management. Once the pitch attitude has been reduced to the desired level, it is

necessary only to reduce the bank angle, ensure that sufficient airspeed has been achieved, and return the airplane to level flight.

148-NOSE LOW, HIGH BANK ANGLES. The nose-low, high-angle-of-bank upset requires prompt action by the pilot as potential energy

(altitude) is rapidly being exchanged for kinetic energy (airspeed). Even if the airplane is at a high enough altitude that ground impact is not

an immediate concern, airspeed can rapidly increase beyond airplane design limits. Simultaneous application of roll and adjustment of

thrust may be necessary. It may be necessary to apply nose-down elevator to limit the amount of lift, which will be acting toward the ground

if the bank angle exceeds 90 degrees. This will also reduce wing angle of attack to improve roll capability. Full aileron and spoiler input

should be used if



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necessary to smoothly establish a recovery roll rate toward the nearest horizon. It is important to not increase g force or use nose-up

elevator or stabilizer until approaching wings level. The pilot should also extend the speed brakes as necessary.

149-RECOVERY TECHNIQUES It is possible to consolidate and incorporate recovery techniques into two basic scenarios -- nose-high and

nose-low -- and to acknowledge the potential for high bank angles in each scenario described above. Other crew actions such as

recognizing the upset, reducing automation, and completing the recovery are included in these techniques. Boeing and Airbus believe the

recommended techniques provide a logical progression for recovering an airplane. The techniques assume that the airplane is not stalled.

If it is, recovery from the stall must be accomplished first.

150-NOSE-HIGH RECOVERY * Recognize and confirm the situation. * Disengage autopilot and autothrottle. * Apply as much as full nose-

down elevator. * Apply appropriate nose-down stabilizer trim. * Reduce thrust (for underwing-mounted engines). * Roll (adjust bank angle)

to obtain a nose-down pitch rate. Complete the recovery: * When approaching the horizon, roll to wings level. * Check airspeed and adjust

thrust. * Establish pitch attitude.

151-NOSE-LOW RECOVERY * Recognize and confirm the situation. * Disengage autopilot, auto-trim and autothrottle. * Recover from stall,

if necessary. * Roll in the shortest direction to wings level (unload and roll if bank angle is more than 90 degrees). Recover to level flight: *

Apply nose-up elevator. * Apply stabilizer trim, if necessary. * Adjust thrust and drag as necessary.

SUMMARY

152-SUMMARY In summary, upset training is very important to all pilots. Due to the limitation of present training devices, it is impossible for

pilots to experience the actual ‘feel’ of the conditions that can lead to an upset condition. Pilots can be trained for the proper ‘procedure’ to

follow in an upset recovery in simulators. It must be emphasized to them that they are not truly experiencing the symptoms of say a

microburst, wake turbulence or windshear. They must know that the flight control loads and inputs will not be the same as experienced in

an actual event. The most difficult problem to overcome with this threat to your operation, is recognizing the symptoms leading to an upset

condition. Crews must stay constantly vigilant to assure upset conditions are avoided. Avoiding conditions such as thunderstorms, frontal

passage, short spacing behind larger aircraft and over dependency on automation, will reduce the chance of an upset condition. The

operational demand on modern aircraft may make some of condition difficult to avoid. Like any other hazard in aviation, the pilot must be

prepared to face these conditions to safely recover.

COURSE END

153-End of the Course


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