12/7/12 Instrument Approach Plates 1/16 www.navfltsm.addr.com/ndb-appr.htm Instrument Approach Plates The ADF is King! What an incredible advance the NDB and ADF brought to instrument flying. Their capability went vastly beyond that of the four-course radio range. For the first time, an aircraft could now approach an airfield that it could not see, to a runway that it could not see until very near, and safely land. What a boost that gave to airline on- time performance. Using the ADF with the NDB, flights can routinely land in prevailing weather of 600 ft ceiling, or less, and only one-mile visibility. Compare that with the nominal 1000 ft ceiling and three- mile visibility requirement of a VFR flight. The FAA publishes approved instrument approaches for U.S. airports. Aircraft performing instrument approaches must conform to these published procedures. Instrument Approach Plates, as these charts were once officially called but now Instrument Approach Procedures, are published for and named after the Navaid used for the approach. This could be an NDB, VOR, ILS, LOC, RNAV, or GPS. Some approaches also require DME or availability of airport radar. Only NDB approaches will be discussed here. Master them and all of the other approaches follow easily. Note that the entire discussion pertains to approaches to airports in instrument conditions. Nowhere is the word "landing" used. That is
Transcript
12/7/12 Instrument Approach Plates
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Instrument ApproachPlates
The ADF is King!
What an incredible advance theNDB and ADF brought toinstrument flying. Theircapability went vastly beyondthat of the four-course radiorange. For the first time, anaircraft could now approach anairfield that it could not see, to arunway that it could not see untilvery near, and safely land. Whata boost that gave to airline on-time performance.
Using the ADF with the NDB,flights can routinely land inprevailing weather of 600 ftceiling, or less, and only one-milevisibility. Compare that with thenominal 1000 ft ceiling and three-
mile visibility requirement of a VFR flight.
The FAA publishes approved instrument approaches for U.S. airports.Aircraft performing instrument approaches must conform to thesepublished procedures. Instrument Approach Plates, as these charts wereonce officially called but now Instrument Approach Procedures, arepublished for and named after the Navaid used for the approach. Thiscould be an NDB, VOR, ILS, LOC, RNAV, or GPS. Some approachesalso require DME or availability of airport radar.
Only NDB approaches will be discussed here. Master them and all of theother approaches follow easily.
Note that the entire discussion pertains to approaches to airportsin instrument conditions. Nowhere is the word "landing" used. That is
in instrument conditions. Nowhere is the word "landing" used. That isthe pilot's decision within the limits of each published approachprocedure.
Yes, despite the emphasis that follows on IFR approaches, aircraft dotake off in IFR conditions, too. In the absence of countermanding limitsat specific airports, a one or two engine aircraft must have at least one-mile visibility to take off. Aircraft with more than two engines requireonly a half-mile visibility. In neither case are ceilings specified. Individualairports may have minimum ceiling requirements, with 300 ft. being verycommon.
A pilot is advised to carefully consider whether to takeoff at theseminimums. If the minimum conditions for takeoff are 300 ft. and one-mile, but the only IFR approach procedure requires 500 ft and one-mile,a return to the airport for whatever reason would not be possible.
The Approach Plate
The layout and content of all U.S. approach plates is identical. Theeasiest way for a flight-simmer to download official U.S. approach platesfor free is to go to AirNav.com and enter the ICAO code for the airportof interest (like KBOS for Boston Logan International). Then scrolldown the airport page where you will find individual links for eachapproach plate and departure procedure for that airport.
One may also purchase paper versions, eiither bound in volumes or inloose-leaf format, from a multitude of online retailers (search AviationCharts) or directly from the FAA.
The FAA has divided the U.S. into twenty-four regions as shown in theillustration below. In 2008 the publication price for any one region is$4.60.
In the meantime, click on the Millville NDB approach plate at the top ofthis section for a full-detailed print.
Twenty-four volumes of Terminal Procedures cover the contiguous48 states.
One brief note on the ILS, the granddaddy of all of the instrumentlanding systems, before moving on. The ILS, or Instrument LandingSystem, is a precision approach system. It provides glide-pathinformation in addition to a localizer signal to guide the aircraft to therunway. None of the other approach procedures provide glide-pathinformation and hence are called non-precision approaches. ILS landingminimums are lower than all of the other approach procedures.
Approach Plate Features
The most efficient way to explain the features of an approach plate is towork from the top-left to the bottom-right. Following the explanationswill be easier, though, if you first print Millville's NDB Runway 14approach plate.
The Left Header
The left header identifies the City and State where the airport is located,
here Millville, New Jersey. Below that, from left to right, is importantInstrument Approach information:
NDB RNB 363 is the Navaid information for this approach ...NDB identifies this as an Approach Procedure using an NDB,RNB is the three-letter identifier of the NDB, and 363 is the NDBfrequency, here 363 kHz.
APP CRS 147° is the Magnetic Course to the runway for thisInstrument Approach.
Rwy ldg 5057 is the available length of runway for landing,here 5057 feet.
TDZE 81 is the Touch Down Zone Elevation of the runway,above Mean Sea Level, MSL. Here it is 81 feet. The TDZ is thatportion of the runway where an aircraft's landing gear normallyfirst contacts the runway when landing.
Apt Elev 85 is the Airport Elevation at some central point. Hereit is 85 feet, or four feet higher than the TDZE of Rwy 14.
The Right Header
The right header identifies the specifics of the approach: The Type ofApproach, which Runway, and the Airport Name.
This Instrument Approach Plate (IAP) describes the procedure for anNDB approach to Runway 14.
Below that is the airport name, Millville Municipal, followed by its threeor four letter airport designator, MIV. The airport name is important forcities with several airports. Be certain you've got the right approach platein front of you.
In some cases, a runway is not listed in the header, for example, VOR–
A. That means that the published approach path is not aligned within 30°of any runway heading. In that case, once the airport is in sight theaircraft must turn to line up with the desired runway.
Second Row – Left Side
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The next box down is general flight information related to the airport.Millville Municipal Airport is a small field, two paved runways and nocontrol tower. With only 164 flight operations per day one would notexpect many airport remarks.
The white "T" in the black triangle indicates that the takeoff minimumsare non-standard, that there is a published departure procedure, or someother issue demands the pilot's attention. You will find this informationin the front of the paper approach chart booklet, or if you download theapproach plates, the departure info will also be linked there.
At Millville, the take-off minimum is 300 ft ceiling and one-mile visibilityfor all categories of aircraft. A published departure procedure also exists,named LEEAH THREE. Here is the LEEAH THREE departure routedescription when take-off is from Runway 10 or 14:
Turn left to heading 109° and intercept OOD R–154 (OODVOR, 154° radial) to LEEAH INT, then via your assignedroute ... Maintain 1800 ft., expect filed altitude 10 minutesafter departure.
The standard takeoff minimums are for aircraft with two engines or lessis one statute mile. For aircraft with more than two engines the take-offminimum is one-half statute mile. In both cases, no ceiling is specified.
And finally, the note in the box above ...
When VGSI inop, straight-in/circlingRwy 14 procedure NA at night.
informs pilots that if the Visual Glide Slope Indicator (red and whitelights adjacent to the runway) are inoperative that straight in or circlingapproaches to Rwy 14 are not authorized at night.
Second Row – Center Section
The center section of the second row defines the Approach LightingSystem for the specific runway listed on the approach plate that you areusing. Runway 14 at Millville, while lighted for night operations, has noapproach lighting system on that runway. So let's take a look at theheader information, second row, for the ILS RWY 17 approach atManchester, New Hampshire, KMHT.
MALSR designates a Medium intensity ApproachLighting System with Runway alignment indicator
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Lighting System with Runway alignment indicatorlights. The dot on the A5 symbol denotes thepresence of sequenced flashing lights ... a "Rabbit."Explanations of the various approach lightingsystems, and there are many, appear in the
Instrument Approach Plate booklet.
Second Row – Right Side
Looking again at the NDB RWY 14 approach at Millville, New Jersey,the right side of the second row of header information provides theMissed Approach Procedure.
Third Row – Communication Frequencies
There are five sections in the row of communications frequencies. Theyare placed in the order that an arrival aircraft would need them:
Again we will look at two different examples, Millville, New Jersey andManchester New Hampshire.
Uncontrolled Field ... No Control Tower
First Millville, an airport with no control tower. From left to right in rowthree of the MIV NDB Rwy 14 Approach Plate here is what is provided:
ASOS is Automated Surface Observation System,which continuously measures and broadcasts, minuteby minute, the surface weather conditions at anairport. The Millville information is available on
128.125 MHz.
Approach Control Service is provided byAtlantic City Airport, KACY, 23.6 nmeast. Contact Approach Control on 124.6MHz (327.125 MHz if military).
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MHz (327.125 MHz if military).
Millville Radio is an Automated FlightService Station, AFSS, connected to adistantly-located service center. File,open and close flight plans, get in-flight
weather btiefings.
Pilots use Unicom to contact an operator at thefield for airport info; active runway, winds,what sort of operations are currently underway,etc.
Common Traffic Advisory Frequency ... Thefrequency to use when announcing yourintentions to land, takeoff, enter the trafficpattern, etc. at this uncontrolled field. Other
aircraft using Millville will also have their Comm radios tuned to thisfrequency. The "L" in the black oval indicates that the airport lights canbe turned on by the aircraft radio (by clicking the Mic button adesignated number of times).
Controlled Field ... Control Tower available
Here is the radio frequency information contained in the five boxes ofrow three on the approach plate for a field with a control tower. Thisexample is for the ILS Rwy 17 approach to Manchester airport, NewHampshire, KMHT. Again it is in the order that arriving aircraft needs it.
Automatic Terminal Information Service broadcastsrecorded information pertaining to the airport.Typically this includes sky conditions, ceilings,
winds, runways in use and any important NOTAMS. ATISinformation is updated hourly and the reported name changes eachhour. The name is the phoenetic alpahabet, Alpha to Zulu. ATIS endswith the announcement "Inform the controller that you have
'Information Bravo' (or whatever happens to be the current phoneticletter.)
Approach Control Service, likeMillville, N.J., is provided by a distantfacility. In this case it's from BostonLogan International airport although
Manchester has its own frequency. Boston Logan is 39 nm SE.
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The Control Tower manages andcontrols all aircraft operations on theactive runways including takeoffs,landings, and exit and entry to the
active runway while on the ground.
Ground control manages and controls all aircraftoperations on the airport property except on activerunways. Principally taxi information andauthorization to and from runways.
Frequency for filing, opening, closing or receivinga flight plan.
Plan View Panel
We're back to the NDB RWY 14 approach at Millville, New Jersey. Thelargest section of an approach plate is the plan view, or "top view" of theapproach.
The Plan View Panel has two components: the Minimum Safe Altitudewithin a 25 nm radius in the lower right-hand corner (can be in anycorner) and the plan-view, or overhead view, of the approach in thecenter.
Minimum Safe Altitude—MSA
The minimum safe altitude—MSA—within 25 nm is shown inside a
circle on the plan view. MSA provides 1000 ft. of clearance from allterrain and known obstructions. The 25 nm radius circle is centered onthe Navaid used for the approach. For Millville that's the RNB NDB,and for Manchester it's the MHT VOR. RNB and MHT are the three-letter designators for the respective Navaids.
Note that the center symbol in the MSA diagram corresponds to the typeNavaid used for the approach, or will be a waypoint symbol if flying aGPS approach.
If you are within 25 NM of Millville, you must fly at or above 2100 ft toclear all obstructions by at least 1000 ft. This MSA is independent ofyour magnetic heading towards RNB NDB.
More than one MSA can be designated for any given approach Navaid,as the Manchester diagram shows. Here are the three MSAs for theMHT VOR:
3500 ft if approaching from the North, magnetic course between046° and 226°.
046° and 226°.2600 ft if approaching from the East, magnetic course between226° and 316°.2000 ft if approaching from the South, magnetic course between316° and 046°.
Note that the direction of fligh for multiple MSAs is defined by yourMagnetic Course not your heading.
Click the image to print this plate imprinted with the identifyingletters.
Centered in the plan view are the "horizontal" details of the instrumentapproach. Horizontal details mean that no altitude information can beobtained from this portion of the plate. That information appear in theprofile view, in the next-described panel.
The plan-view features are explained below in the order that a pilotconfronts them. Letters "A" through "K" defines this sequence. Click onthe image above to print the approach plate imprinted with theseidentifying letters to follow the explanation.
A. Identify the NDB—be certain that you are approaching the correctbeacon. Frequency indication on the receiver is not sufficientbecause LF beacons can have great range. Listen for the identMorse code as shown in the Navigation box. The IAF at the top ofthe box means that this Navaid is the Initial Approach Fix for thisinstrument approach. All approaches start somewhere, and thatplace is the IAF.
B. The Navaid here is Rainbow NDB, ident RNB. Approach theairfield by tracking to the NDB.
C. On reaching the IAF, turn OUTBOUND from the airport. In thiscase, the track (compensating for wind) should be 327°.
D. Track outbound from the IAF for two minutes, then start theprocedure turn. Here it is a left turn to 282°. Note that the line witha half-arrow head indicates that a procedure turn is a mandatorypart of the approach procedure.
E. Proceed on the 282° heading for a minute or so, then turn AWAYfrom the airport to the reciprocal heading of 102° to return back tothe approach course to the field.
F. As the ADF indicator nears the 147° bearing to the NDB, turninbound, right in this case, and track to the NDB on that bearing.
G. Continue inbound until the field and runway 14 is in sight. Theminiature airport plan "G" accurately portrays the runway layout inrelation to your inbound track.
H. If the runway is not in sight when it should be, a missed approachis mandatory. "H" shows that a right turn is required to perform amissed approach.
I. The missed approach procedure generally sends the aircraft to theNavaid and into a holding pattern to await further instructions fromATC. "I" shows the holding pattern and the proper headings. Italso shows, in this case, that the holding pattern requires rightturns.
turns.J. Before beginning the approach, take note of the obstructions. By
now you are aware that antenna towers seem to cluster nearairports. Know generally where they are and their height.
K. The circle surrounding the plan view of the approach procedure is10 nm in radius, centered on the Navaid. You are expected toremain within this 10 nm. distance from the beacon whileperforming the approach. i.e., don't fly a 20 nm outbound leg, or15 nm after turning into the procedure turn. You only own theairspace within the 10 nm radius circle.
OK, I give up—what's a procedure turn?
Looking again at the approach plate, your flight path brings you to thebeacon, RNB, then you fly outbound from the beacon, away from theairport and runway. Obviously you have to get turned around to returnto the airport, and the procedure turn is a standardized way of doingthat.
It's common to execute the procedure turn about two minutes out from
the beacon. That time is flexible, but too little rushes you too much onthe return to the beacon and too long may take you outside themandatory 10 nm. radius that you must remain within.
There's an unpublicized hazard, too, with a procedure turn that begins aloooong way out from the beacon. That's the bevy of pilots of high-performance aircraft asking to see you, the ones that you delayed whileyou moseyed that long distance back to the beacon at a nice leisurelypace.
The procedure turn begins with a 45° turn away from the outboundtrack. Fly that heading for a minute or so, nothing hard and fast aboutthat time, then execute a 180° turn away from the airport to return to thedesired bearing to the beacon.
When you intercept the desired inbound bearing to the beacon, actuallyjust shortly before that point, you make another 45° turn, this timetoward the airport, nicely rolling out on the specified track back to thebeacon.
The approach plate defines the direction of the procedure turn from theoutbound track. There is no freedom in that: what the chart shows ismandatory.
Approach—Profile
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As just seen, the plan view on the approach plate gives no altitudeinformation. That information is on the profile view.
Considering the approach again, the aircraft flies outbound, tracking327° from the NDB. Notice the underlined 2000 in the profile view.That indicates that the aircraft may not descend lower than 2000 ft MSL
while outbound and in the procedure turn.
Once the aircraft is inbound, tracking 147° to the beacon, it maydescend further, but no lower than 1300 ft. until it reaches the beacon,also referred to as the FAF or Final Approach Fix. From that point itmay begin its descent to the MDA, or Minimum Descent Altitude, whichis discussed on the next part of the approach plate.
The heavy line to the right of the beacon signifies the runway. Here, it is3.7 nm from the beacon, a crucial number to know in a non-precisionapproach, where distance is gauged by time.
How low can you go? What are the minimum visibility requirements?Read on.
Minimums
The minimums table is immediately below the profile view.
Landing minima are established for six categories of aircraft; ABCDEand COPTER. An aircraft fits into one category or another based on itsmaneuvering speed. Maneuvering speed is defined as 1.3 times the stall
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maneuvering speed. Maneuvering speed is defined as 1.3 times the stallspeed at maximum gross weight in the landing configuration. The tablebelow identifies the Category vs. Maneuvering Speed.
ApproachCategory
A B C D E
Speed (Knots) 0–90 91–120 121–140 141–165 Abv 165
Note that approach plate lists only the first four categories.
The next two rows list the minima for the two possible types of landingwith this procedure: Straight in to runway 14 (S–14), or Circling to landat any of the other available runways. A Straight landing is defined asone where the approach course is aligned within 30° of the runwayheading.
The straight-in landing minima at Millville for runway 14 is 560 ft.Minimum Descent Altitude (MDA) and one statute mile reportedvisibility for Categories A and B aircraft. The MDA remains the samefor C and D, but the visibility minimums increase to 1¼ and 1½ statutemiles respectively.
MDA is exactly as the words say. The aircraft may not descend belowthe Minimum Descent Altitude during an approach unless the approach-end of the runway is firmly in sight, and a safe, normal visual landingcan be made. No diving to the runway hoping to touchdown on the lastquarter of its length.
Ignore the numbers in the parenthesis; they apply to military aircraftonly. The small numbers just before the parenthesis is the actual heightof the MDA above the airport. This may not be the mathematicalsubtraction of ceiling and field elevation, because field elevation andairport height can differ by several feet.
Note that some of the landing minima for a circling approach are slightlyhigher than for a straight-in approach.
Airport Plan View
The plan view of the airport isan important feature of theapproach plate. The fieldelevation is noted in the upperleft-hand corner of this view.Millville's elevation is 85 ft.
This view gives the pertinentdetails of the runways; theirlength and width, and therunway numbers. Note the"TDZE 81" for Runway 14.That is the Touch Down ZoneElevation for Runway 14.Recall in the minimums tablethat for the S–14 approachwith an MDA of 560 ft, theheight above the airport wasshown as 479 ft? That wasobtained by subtracting the 81
ft TDZE from 560 ft MDA.
Recall also on the plan view of the approach, that two runways were inthe little diagram at the end of the approach arrow? The airport planview shows that runways 10–28 and 14–32 are available.
The airport plan view also reminds the pilot that Rwy 14 is 3.7 nm fromthe FAF, Final Approach Fix, which is the NDB, and that the approachcourse is 147°.
At the bottom of the view is the runway lighting information. HereMIRL, Medium Intensity Runway Lights, are available on both runwaysand are pilot controlled.
The Black circle with a white "A5" inside of it near Rwy 10 indicates thetype of lighting. A white letter in a black circle denotes that the lights arepilot controlled. The dot at the top of that black circle indicatessequenced flashing approach lights–called "the rabbit" by pilots becausethey chase it down to the end of the runway.
If the airport is large, its plan view occupies an entire page of theapproach plate booklet.
Time from FAF to MAP
FAF to MAP 3.7 NM
Knots 60 90 120 150 180
Min: Sec 3:42 2:28 1:51 1:29 1:14
Distances in a non-precision approach are gauged by measuring time.The critical time of a non-precision approach is from the FAF, or Final
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The critical time of a non-precision approach is from the FAF, or FinalApproach Fix (the NDB) to the MAP, Missed Approach Point, or touchdown zone of the runway. The times to cover this distance, 3.7 nmhere, are calculated and entered into a table located below the airportplan view.
It would be nice if our aircraft, considering any wind component,approached the MAP at a speed exactly listed in the table. Seldomhappens, so interpolation is needed. Assume you approach in your BarnBurner at 75 knots, midway between two entries in the table.Recalculate for your 75 kt approach speed, 2 min., 58 sec., and jot thattime down on your clipboard so that it will be available when you run
the approach. Don't want to be doing those calculations at the finalmoments of the approach.
It's time to fly the approach. Click on the NDB off Airport button to getinto the soup and see if you can find the runway.
NDB off Airport
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