Landing Gear & Brakes Flashcards
How does the nosewheel steering operate?
Hydraulically actuated through a steering actuator mounted on the nose landing gear assembly. There is no mechanical connection between the flight deck controls and the steering actuator. Nosewheel steering commands are transmitted electronically using “steer-by-wire” technology.
How is the NOSE STEER activated?
Switch is armed and hydraulic system 3 is pressurized, the nose landing gear is down and locked, and the PSEU (Proximity Sensor Electronic Unit) “ground” mode is satisfied.
Electronic Control Unit (ECU) does what to the Nosewheel steering?
Controls the electrohydraulic valve that directs hyd system 3 pressure to the steering actuator to turn the nose wheels. The ECU continuously monitors the nose wheel steering system. In the air it centers the nose wheel.
How many brake applications are available if both hydraulic systems 2 and 3 have failed?
Accumulators in both hydraulic brake systems provide pressure for approximately six brake applications with the anti-skid selected off.
Upon landing, when does anti-skid braking become available?
35-knot wheel spin-up signal is generated or a WOW signal is present after a 5-second delay. The anti-skid system is functional down to a minimum well spin of 10 knots.
Where can the brake cooling charts be located?
AFM
During landing gear manual extension, which hydraulic system assist the MLG into the locked position, if available?
If available, hydraulic system 2 assists the MLG into the locked position.
How many fusible plugs does each main wheel have?
Four fusible plugs that melt to prevent tire burst in the event of an overheated wheel or brake condition.
Braking
Loss of either hydraulic system 2 or 3 results in what?
A 50% reduction in braking capability. Braking remains symmetrical and anti-skid is available at the working brakes.
Parking brake when the hydraulic systems are selected off, which brakes will hold for a prolonged period?
Inboard brakes. System 3
How is wheel lockup avoided?
Anti-Skid Control Unit (ASCU) modulates the hydraulic pressure at the brake. In the air mode (no WOW signal), the ASCU configures the anti-skid valves to full brake dump, to prevent wheel lockup at touchdown.
Landing gear horn has sounded for more than 10 seconds will get you what?
Gear will be displayed in amber and flash.
Pulling the LANDING GEAR MANUAL RELEASE handle does what?
Releases the nose gear forward door uplock and the three landing gear uplocks. In addition, the handle operates dump valves that remove hydraulic pressure, allowing the gear to free-fall.
