Landing Gear Flashcards
The autobrake system can only be armed if the normal brake system is operational. ________are provided
during autobrake operation.
Antiskid,
touchdown and
locked wheel protections
Two proximity sensor electronic modules (PSEM) process signals from the ____weight-on-wheels (WOW) proximity sensors to determine if the airplane is on ground or in flight. ___ WOW sensors are installed on each landing gear.
6
2
If two WOW sensors on the same landing gear leg fail, the PSEMs will activate a logic that prevents the landing gear lever from moving up.
.
the landing gear is locked in the fully
extended position by the downlock springs.
.
When retraction is completed, the landing gear is held in place by uplocks
,
Electrical Override Extension
(1) When the landing gear lever control box fails the electrical override system is used to extend the landing gear.
(2) The electrical override system bypasses the PSEM and commands gear extension in the same sequence as the normal operation.
.
Alternate Gear Extension
(1) If hydraulic pressure is not available for landing gear operation or the electrical system fails, landing gear extension is performed by the alternate gear extension lever
2) Pulling up the alternate gear lever releases residual hydraulic pressure in the landing gear lines and opens all landing gear uplocks.
(3) The landing gear extends in a free fall with the aid of gravitational and aerodynamic forces.
(4) In the unlikely event that one main gear does not lock down, it may be necessary to slip the airplane using aerodynamic drag to lock the affected
leg.
.
DOWN/UP LOCK SENSORS
A. Each landing gear has two uplock sensors and two downlock sensors.
B. In the event of a discrepancy between both uplock or downlock sensors of the same landing gear, the sensor in agreement with the landing gear lever position will be considered valid
.
During normal operation the brake control modules (BCM) provides protection from skidding and locking of the main wheels. It also has some functions to improve the braking performance.
The BCM main functions are:
(1) Locked wheel protection.
(2) Antiskid protection.
(3) Automatic wheel braking.
(4) Touchdown protection
During normal operation the brake control modules (BCM) provides protection from skidding and locking of
the main wheels. It also has some functions to improve the braking performance.
The BCM main functions are:
(1) Locked wheel protection.
(2) Antiskid protection.
(3) Automatic wheel braking.
(4) Touchdown protection
LOCKED WHEEL PROTECTION
A. Locked wheel protection is active anytime on ground and at wheel speeds above __kt.
B. The system logic compares wheel speed signals between the left and the right inboard brakes or between the left and the right outboard brakes. If a wheel speed is __% or below its associated paired wheel speed, the brake control module commands zero pressure to the brake of the slower wheel, thus allowing speed equalization
30 kts
33%
ANTISKID PROTECTION
A. Anti skid protection prevents tire skidding and maximizes brake efficiency according to the runway surface.
B. The system controls the amount of hydraulic pressure applied to the brakes and, if necessary, reduces the wheel brake pressure in order to recover wheel speed and prevent tire skidding.
C. For wheel speeds below ___kt, the anti skid protection is deactivated, thus allowing the pilot to lock and pivot on a wheel for maneuvering.
D. Anti skid protection is not available for the emergency/parking brake system
10
TOUCHDOWN PROTECTION
A. Touchdown protection prevents the airplane from touching down with the main landing gear brakes applied.
B. It is deactivated:
(1) ___seconds after WOW has sensed the ground; or
(2) When wheel speed is above ___kt
three
50
TOUCHDOWN PROTECTION
A. Touchdown protection prevents the airplane from touching down with the main landing gear brakes applied.
B. It is deactivated:
(1) ___seconds after WOW has sensed the ground; or
(2) When wheel speed is above ___kt
three
50
he Emergency/Parking brake is operated through a handle located on the pedestal control panel and is powered by hydraulic systems 1 and 2.The emergency/parking brake system has pressure accumulators isolated from both normal hydraulic systems. The accumulators have sufficient pressure to provide ___full brake applications
6
