What gas, and what fluid are normally contained in an oleo type shock absorber?
Air/(N2), and hydraulic fluid
What restricts the flow of fluid within the oleo?
Describe the operation of a shock strut (oleo) and its internal components
The strut absorbs the landing impact as oil transfers from the oil chamber into the air chamber around the metering pin (or through a calibrated orifice) as the piston is forced into the cylinder by the weight of the aircraft. Taxi shocks are dampened by the compressed air in the air chamber.
Explain the maintenance and servicing (initial/full) of a shock strut (oleo), in approximately 14 steps.
1. Clean around filler plug, 2. Jack aircraft, 3. Depressurize strut through charging/air valve, 4. Remove filler plug, 5. Compress strut fully, 6. Fill strut with appropriate hydraulic fluid, 7. Install filler plug, 8. Extend and compress strut several times to remove trapped air, 9. Remove filler plug, 10. Compress strut, 11. Ensure fluid level is satisfactory, 12. Install filler plug, 13. Remove aircraft from jacks, 14. Inflate strut to expose correct amount of piston tube
When disassembling the strut what important safety precaution should be observed in regard to the scraper ring?
The scraper ring may wear sharp so use caution when handling and removing
Should the air valve core be removed from the filler plug body when disassembling the strut or to remove the nitrogen pressure if the valve core assembly is not being replaced?
When inflating the nose gear strut to test for leaks, what is the recommended inflation pressure?
What are some causes of “spongy braking action”?
Air in the lines/ or deterioration of the flexible lines
What is the advantage of the carbon brake? -Light weight, and can absorb tremendous amounts of heat. or -Inexpensive to replace.
Light weight, and can absorb tremendous amounts of heat.
What caution should you be aware of when using a pressure pot to bleed a brake system?
Ensure you have the correct type of fluid.
Breaks- What do we do in regards to leaking fluid line connections?
The fittings should be checked for the proper torque.
Are modern single disk brakes self adjusting?
Why are their slots cut into the stationary disks in the multi disk brake setup?
To allow for expansion as the disk gets hot.
Carbon brakes are primarily used on what type of aircraft?
Jet transport aircraft.
General aviation aircraft are equipped with what type of brakes?
Single disk actuator, fixed disk type.
Under normal foot braking conditions when the brakes are applied, does the fluid flow into the thermal relief valve piston area? yes or no
When the park brake has been applied, can fluid flow back to the reservoir from the brake unit at the wheel? yes or no
When the master cylinder is in the static position (brake and park brake in the off position) is the poppet valve in the piston head normally open or closed?
When the park brake has been applied, can fluid flow from the reservoir to the master cylinder and into the chamber where the spring #10 is located? yes or no
Can fluid flow to or access the thermal relief piston from the brake unit at the wheel when the park brake is applied? yes or no
If poppet valve leaks slowly, when the brakes are applied what will happen? -the brake pedal will slowly bleed down and the brakes will release unless pumped up again or -brakes will lock on after application and stay locked on after foot pressure is released
the brake pedal will slowly bleed down and the brakes will release unless pumped up again
Why must the brakes on this system be applied to release the park brake poppet valve? -to allow fluid to the brake to release the back pressure resisting assembly releasing the brake or -to equalize the pressure on both sides of the park brake poppet valve and allow the spring to open the park brake poppet valve allowing fluid flow from the brake unit
to equalize the pressure on both sides of the park brake poppet valve and allow the spring to open the park brake poppet valve allowing fluid flow from the brake unit
what is 5 ,6 and 7
•5. Pressure out to brake
•6. Parking brake poppet valve
•7. Thermal relief chamber
Why bleed brakes ?
to prevent spongy braking action and restore the proper brake function
what is 1 and 2
•1. Piston rod
•2. Poppet valve