2121 S. Hoover Road Wichita, KS 67209
844-44TXTAV 844-448-9828
TMDA#: 92019 Date: 7-2-2018
Part Number of Publication:
PCR Number:
Removes the requirement for a system leak check unless a bottle is
replaced or a leak is suspected.
See attached draft for changes.
92019
Reviewer is acting as a representative of Cessna Aircraft Company.
TMDA information is Cessna/FAA approved for installation on Cessna
airplanes in original or Cessna modified configurations, only. The
supersedure/alternate part information for Cessna proprietary parts
is approved based on current Cessna approved engineering, as of the
date specified. Supersedure/altemate part information for
non-proprietary parts is accurate based on available source
information as of the date specified. For further validation of
non-proprietary parts contact the manufacturer.
Page 1 of 1 CSF-003 Rev. 9/15
CESSNA® MODEL 680A
1. General
A. This section gives the servicing procedures for the landing gear
and brake emergency pneumatic systems. The landing gear and brake
emergency pneumatic systems servicing includes the emergency gear
extension pneumatic bottle and the emergency brake pneumatic
bottle.
B. For the emergency gear extension pneumatic bottle and the
emergency brake pneumatic bottle fluid and capacity, refer to
Replenishing - Description and Operation.
2. Emergency Gear Extension Pneumatic Bottle Servicing
A. Tools and Equipment
NOTE: For the tool, equipment, and special consumable part numbers
and the manufacturer data, refer to Chapter 32, Landing Gear -
General. For the supplier publication part number and manufacturer
data, refer to the Introduction - Supplier Publication List.
(1) Tools and Equipment Digital Thermometer.
(2) Special Consumables Dry Nitrogen.
(3) Reference Material Chapter 6, Dimensions and Areas -
Description and Operation Chapter 6, Access Plates and Panels
Identification - Description and Operation Chapter 7, Lifting -
Maintenance Practices Chapter 12, High-Pressure Pneumatic Service
Valve - Servicing Chapter 12, Hydraulic Reservoir - Servicing
Citation Standard Practices Manual, Chapter 20, Safetying -
Maintenance Practices Chapter 24, External Electrical Power -
Maintenance Practices Chapter 29, Hydraulic Power - Maintenance
Practices.
B. Prepare the Airplane for the Emergency Gear Extension Pneumatic
Bottle Servicing. (1) Open the left nose access door to get access
to the emergency gear extension pneumatic
bottle pressure gage and the emergency gear extension pneumatic
bottle. Refer to Chapter 6, Dimensions and Areas - Description and
Operation.
(2) If the emergency landing gear extension system was operated, do
the steps that follow: (a) Manually reset the control arm on the
emergency gear extension pneumatic bottle
and safety. Refer to the Citation Standard Practices Manual,
Chapter 20, Safetying - Maintenance Practices.
NOTE: When you operate the emergency landing gear extension system,
the control arm on the emergency gear extension pneumatic bottle
latches in the discharge position. It is necessary to push in the
knob for the emergency gear extension pneumatic bottle control
cable before you can reset the control arm. You can use a number 40
drill bit or equivalent to release the pin from the control
arm.
(b) Remove fuselage access panel 316AR to get access to the landing
gear control manifold assembly. Refer to Chapter 6, Access Plates
and Panels Identification - Description and Operation.
(c) Push the pneumatic override valve on the landing gear control
manifold assembly in to reset it to the detent position.
NOTE: When you operate the emergency landing gear extension system,
the pneumatic override valve on the landing gear control manifold
assembly latches in the override position. It is necessary to push
in the override valve to reset it to the usual position.
12-10-45 Page 301 © TEXTRON AVIATION INC. Mmm DD/YYYY
CESSNA® MODEL 680A
MAINTENANCE MANUAL
(d) Install fuselage access panel 316AR. Refer to Chapter 6, Access
Plates and Panels Identification - Description and Operation.
(e) Raise the airplane on jacks. Refer to Chapter 7, Lifting -
Maintenance Practices. (f) Connect external electrical power to the
airplane. Refer to Chapter 24, External Electrical
Power - Maintenance Practices. (g) Connect external hydraulic power
to the airplane and set it to 3000 psi (20,684 kPa) at
6 gallons per minute (22.7 liters-per-minute). Refer to Chapter 29,
Hydraulic Power - Maintenance Practices.
(h) Operate the landing gear through 10 to 15 cycles to remove the
nitrogen from the hydraulic system.
NOTE: When you operate the emergency landing gear extension system,
the dry nitrogen gas from the emergency gear extension pneumatic
bottle goes into the hydraulic system. It is necessary to operate
the landing gear to remove the dry nitrogen gas from the hydraulic
system.
(i) Bleed the Hydraulic System Fully with the Airplane on Jacks.
Refer to Chapter 12, Hydraulic Reservoir - Servicing,
(j) Disconnect external hydraulic power from the airplane and
release the pressure. Refer to Chapter 29, Hydraulic Power -
Maintenance Practices,
(k) Disconnect external electrical power from the airplane. Refer
to Chapter 24, External Electrical Power - Maintenance
Practices.
(I) Lower the airplane and remove the jacks. Refer to Chapter 7,
Lifting - Maintenance Practices.
C. Do the Emergency Gear Extension Pneumatic Bottle Servicing
(Refer to Figure 301). (1) Remove the cap from the service valve of
the emergency gear extension pneumatic bottle
pressure gage. (2) Connect a dry nitrogen source to the service
valve. Refer to Chapter 12, High-Pressure
Pneumatic Service Valve - Servicing. (3) Monitor the emergency gear
extension pneumatic bottle pressure gage and service the
emergency gear extension pneumatic bottle to the correct pressure
as shown on the nose gage placard on the forward pressure
bulkhead.
(4) Disconnect the dry nitrogen source from the service valve.
Refer to Chapter 12, High-Pressure Pneumatic Service Valve -
Servicing.
(5) Install the cap on the service valve of the emergency gear
extension pneumatic bottle pressure gage.
I (6) If the servicing is for a replaced pneumatic bottle or a leak
is suspected, complete a leak check. Refer to the Emergency Gear
Extension Pneumatic System Leak Check in this section.
D. Put the Airplane Back to its Initial Condition. (1) Close the
left nose access door. Refer to Chapter 6, Dimensions and Areas -
Description and
Operation.
A. Tools and Equipment
NOTE: For the tool, equipment, and special consumable part numbers
and the manufacturer data, refer to Chapter 32, Landing Gear -
General. For the supplier publication part number and manufacturer
data, refer to the Introduction - Supplier Publication List.
(1) Tools and Equipment Digital Thermometer.
(2) Special Consumables Dry Nitrogen.
(3) Reference Material Chapter 6, Dimensions and Areas -
Description and Operation Chapter 12, High-Pressure Pneumatic
Service Valve - Servicing Chapter 32, Main Landing Gear Brake
Control System - Adjustment/Test.
12-10-45 Page 302 © TEXTRON AVIATION INC. Mmm DD/YYYY
CESSNA® MODEL 680A
MAINTENANCE MANUAL
Landing Gear and Brake Emergency Pneumatic Systems Servicing Figure
301 (Sheet 1)
B. Prepare the Airplane for the Emergency Brake Pneumatic Bottle
Servicing, (1) Open the left nose access door to get access to the
emergency brake pneumatic bottle pressure
gage. Refer to Chapter 6, Dimensions and Areas - Description and
Operation. (2) Open the right nose access door to get access to the
emergency brake pneumatic bottle. Refer
to Chapter 6, Dimensions and Areas - Description and Operation. (3)
If the emergency brake control system was operated, do the Brake
Bleeding. Refer to Chapter
32, Main Landing Gear Brake Control System - Adjustment/Test.
NOTE: When you operate the emergency brake control system, the dry
nitrogen gas from the emergency brake pneumatic bottle goes into
the main landing gear brake hydraulic system. It is necessary to
bleed the brakes to remove the dry nitrogen gas from the
system.
C. Do the Emergency Brake Pneumatic Bottle Servicing (Refer to
Figure 301). (1) Remove the cap from the service valve of the
emergency brake pneumatic bottle pressure gage. (2) Connect a dry
nitrogen source to the service valve. Refer to Chapter 12,
High-Pressure
Pneumatic Service Valve - Servicing. (3) Monitor the emergency
brake pneumatic bottle pressure gage and service the emergency
brake
pneumatic bottle to the correct pressure as shown on the nose gage
placard on the forward pressure bulkhead.
(4) Disconnect the dry nitrogen source from the service valve.
Refer to Chapter 12, High-Pressure Pneumatic Service Valve -
Servicing.
(5) Install the cap on the service valve of the emergency brake
pneumatic bottle pressure gage. (6) Do a leak check as
follows:
(a) Let the system become stable for 30 minutes. (to) Record the
pressure shown on the emergency brake pneumatic bottle pressure
gage. (c) Use a digital thermometer to record the temperature of
the emergency brake pneumatic
bottle. (d) Let the system become stable for 24 hours. (e) Record
the pressure shown on the emergency brake pneumatic bottle pressure
gage. (f) Use a digital thermometer to record the temperature of
the emergency brake pneumatic
bottle. (g) Make sure that the pressure shown on the emergency
brake pneumatic bottle pressure
gage does not decrease after 24 hours.
D. Put the Airplane Back to its Initial Condition. (1) Close the
left nose access door. Refer to Chapter 6, Dimensions and Areas -
Description and
Operation. (2) Close the right nose access door. Refer to Chapter
6, Dimensions and Areas - Description and
Operation.
4. Emergency Gear Extension Pneumatic System Leak Check
A. Do the Emergency Gear Extension Pneumatic System Leak Check. (1)
Let the system become stable for 30 minutes. (2) Record the
pressure shown on the emergency brake pneumatic bottle pressure
gage. (3) Use a digital thermometer to record the temperature of
the emergency brake pneumatic bottle. (4) Let the system become
stable for 24 hours. (5) Record the pressure shown on the emergency
brake pneumatic bottle pressure gage. (6) Use a digital thermometer
to record the temperature of the emergency brake pneumatic bottle.
(7) Make sure that the pressure shown on the emergency brake
pneumatic bottle pressure gage
does not decrease after 24 hours.
NOTE: A 1°F (0.5*C) change in the temperature of the emergency gear
extension pneumatic bottle will result in a 3.5 psi (24.13 kPa)
change in pressure.
12-10-45 Page 303 © TEXTRON AVIATION INC. Mmm DD/YYYY