Chapter 14 Landing gear Flashcards
What speed recstrictions apply to extending and retracting the landing gear?
(FCOM 14.10.1)
Retraction: 235kts
Extention: 270kts
Extended: 320 kts
Max speed in Mach = 0.82M extention and extended.
What does it mean if the top Landing Gear Indicator Lights are RED on without any other indication? (Three lights indicating)
(FCOM 14.10.2)
Related landing gear is NOT down and locked.
What does it mean if the BOTTOM Landing Gear Indicator Lights are GREEN and the TOP Landing Gear Indicator Lights are RED ? (Six lights indicating)
(FCOM 14.10.2)
Related gear IS down and locked.
What does it mean if all six the Landing Gear Indicator Lights are extinguished? (Six lights are blank)
(FCOM 14.10.2)
Landing gear is NOT down and locked.
Note: This is the same as if the top Landing Gear Indicator Lights are RED on without any other indication? (Three lights indicating)
What happens when the landing gear lever is placed in the “OFF” position?
(FCOM 14.10.2 & 14.20.1)
Hydraulic pressure is removed from landing gear system.
Underneath the landing gear lever, there is a red lever that can pushed up, what does this do?
(FCOM 14.20.1)
This lever allows the LANDING GEAR lever to be raised when its bloacked, by bypassing the landing gear lever lock. In flight, the air/ground system energizes a solenoid which opens the lever lock.
Does the Landing Gear Indicator Lights located on the overhead panel have a separate circuit to the main indicator?
(FCOM 14.10.2)
Yes, this indicator is a redundant but separate set of landing gear indicator circuits and lights from the main landing gear indicator located below the MCP.
If the Landing Gear Indicator Lights located on the overhead panel show three green lights, but the Landing Gear Indicator Lights located below the MCP is extinghuished, what does this indiacate?
This indiactes that the bulbs on theLanding Gear Indicator Lights located below the MCP are fused or broken. This also indicates the related gear on the overhaed panel IS down and locked.
Note: Landing gear is down and locked as long as one green landing gear
indicator light (center panel or overhead panel) for each gear is
illuminated.
What will deactive the landing gear warning horn?
(FCOM 14.10.3)
When all three gear switches is detected to be down and locked.
When manually extending the landing gear, how far should the extention handles be pulled out?
To its limit, approximately 24 inches (61 cm).
Note: this is approximately 2 rulers.
When the autobrake selector is placed to “RTO”, when will the autobrake apply pressure?
(FCOM 14.10.4)
If the IAS is ABOVE 88kts, the auto brakes will utomatically apply MAXIMUM brake pressure when thrust levers are retarded to idle.
What is the full range of motion of the nose gear?
(FCOM 14.10.9)
Rudder pedal � turns nose wheel up to 7 degrees in either direction.
Tiller - 78 degrees in either direction.
Which hydraulic normally supplies the landing gear hydraulic pressure?
(FCOM 14.20.1)
A system
Do the wheels spin during retraction?
(FCOM 14.20.1)
No, during retraction, the brakes automatically stop rotation of the main gear wheels. The nose wheels retract forward into the wheel well and nose wheel rotation is stopped by snubbers.
A spinning tire with a loose tread must be stopped prior to entering the wheel well or it can cause damage to wheel well components. How does the 737 prevent this?
(FCOM 14.20.2)
The wheel well system is fiited with a red sensor button reffered to as a ‘fitting’ or 14.20.2. When a spinning tire with loose tread impacts a fitting in the wheel well ring opening, that gear stops retracting and free falls back to the down position. The affected gear cannot be retracted until the fitting is replaced.
Note: The remainder of the flight will be conducted with the gear extended.
What is the purpose of the Landing Gear Transfer Valve?
(FCOM 14.20.2)
To supply the pressurized hydraulic fluid needed to RAISE the landing gear at the normal rate when system A pressure is lost due to No. 1 engine RPM loss. (When engine no.1 falls below 50% N2, the LGTV uses system B hydraulic pressure.
Note: It is for this reason that despatch with Engine No1 tachymeter U/S is NOT permissible on the Classics. On the NG, despatch with the Tachymeter is permissible under the MEL due to the NG sending engine runnnig data digitally to the PSEU.
Note: System B cannot be used to extend landing gear. If system A is lost, manual extention is avaiable, which uses gravity. Once gear has been extended after system A has been lost, the gear cannot be retracted with the the manual extension access door open, because this disables the the gear retraction.
Following a manual gear extention, can the gear be retracted again ?
(FCOM 14.20.2)
Yes, however the manual extention access door must be closed and hydraulic system A pressure available.
Which hydraulic system provide the brakes hydraulic pressure? (FCOM 14.20.3)
System B
What happens to brakes if hydraulic system B is low or fails?
(FCOM 14.20.3)
Hydraulic system A automatically supplies pressure to the alternate brake system.
What happens if If both normal and alternate brake system pressure is lost?
(FCOM 14.20.3)
Trapped hydraulic AND nitrogen pressure in the brake accumulator can still provide several braking applications or parking brake application (Approximately 5. It provides approximately SIX brake applications.
How does the antiskid protection work?
(FCOM 14.20.4)
When the system detects a skid, the associated antiskid valve reduces brake pressure until skidding stops
Does antiskid work with alternate breaks?
(FCOM 14.20.4)
Yes, Antiskid protection is available even with loss of both hydraulic systems. however antiskid protection is applied to main gear wheel pairs instead of individual wheels.
Note: Both normal and alternate brake systems provide skid, locked wheel, touchdown and hydroplane protection.
Does autobrake work with alternate breaks?
(FCOM 14.20.4)
No, the system operates only when the normal
brake system is functioning.
Upon selection, the AUTO BRAKE DISARM light illuminates for one to two seconds and then extinguishes, what does this indicate?
(FCOM 14.20.4)
A automatic self�test has been successfully accomplished. If the turn on�self�test is not successful, the AUTO BRAKE DISARM light illuminates and the autobrake system does not arm.
Will the autobrake RTO funciton work without an antiskid protection?
(FCOM 14.20.4 and Vol46 DDG 32-02-02)
No.
What happens if a landing is made with RTO selected (AUTO BRAKE select switch not cycled through OFF)?
(FCOM 14.20.5)
No automatic braking action occurs and the AUTO BRAKE DISARM light illuminates two seconds after touchdown.
Can Auto brakes be selected after landing?
(FCOM 14.20.5)
Yes, rior to decelerating through 30 kts of ground speed. Braking initiates immediately if the conditions are met.
Note: Thurst levers must be retarded to idle.
How does the aurobrake system work?
(FCOM 14.20.5)
Break pressure is applied to adjust deceleration rate after touch down. Autobrake pressure is reduced as other controls, such as thrust reversers and spoilers, contribute to total deceleration. The autobrake system brings the airplane to a complete stop unless the braking is terminated by the pilot.
Note: Deceleration rate can be changed (without disarming the system) by rotating the selector.
How can the aurobrakes be disarmed?
(FCOM 14.20.5)
- Rotating autobrake selector to “OFF”
- Moving the SPEED BRAKE lever to the down detent
- Advancing the forward thrust lever(s), except during the first 3 seconds after touchdown for landing
- Applying manual brakes.
How is the park brake set?
FCOM 14.20.6
By depressing both brake pedals fully, while simultaneously pulling the PARKING BRAKE lever up.The parking brake can be set with either A or B hydraulic systems pressurized. If A and B hydraulic systems are not pressurized, parking brake pressure is maintained by the brake accumulator
“How is the park brake released?
FCOM 14.20.6”
By depressing the pedals until the PARKING BRAKE lever releases.
How does the aircraf tknow if its airborne or on the ground?
(FCOM 14.20.6)
The Air/Ground System Logic, made up of six sensors, two on each landing gear. These sensors send signals which are used to configure the airplane systems to the appropriate air or ground status.
