AMT AMT Hydraulics, Pneumatics & Landing Gear 2 — Questions and Answers
Question 1: What is the purpose of a shimmy damper on an aircraft nose gear?
- To steer the nose wheel during taxi
- To absorb and dampen rapid oscillations of the nose wheel (Correct answer)
- To prevent gear retraction during flight
- To provide nose gear extension force
Correct answer: To absorb and dampen rapid oscillations of the nose wheel
A shimmy damper uses hydraulic resistance to control and suppress the rapid side-to-side oscillation (shimmy) of the nose wheel during ground operations.
Question 2: Which component absorbs landing shock energy in most aircraft landing gear struts?
- Steel coil spring only
- Rubber biscuits
- Oleo (air-oil) pneumatic strut (Correct answer)
- Leaf spring
Correct answer: Oleo (air-oil) pneumatic strut
Oleo struts use a combination of compressed air/nitrogen and hydraulic oil to absorb and dissipate the energy of landing impact.
Question 3: What safety device prevents accidental retraction of landing gear while the aircraft is on the ground?
- Downlock pin
- Weight-on-wheels (squat) switch (Correct answer)
- Hydraulic pressure relief valve
- Manual gear handle guard
Correct answer: Weight-on-wheels (squat) switch
The weight-on-wheels (squat) switch is a safety switch that senses aircraft weight on the gear and electrically prevents retraction while the aircraft is on the ground.
Question 4: What is the typical inflation medium used in aircraft oleo struts?
- Compressed air only
- Nitrogen gas and hydraulic oil (Correct answer)
- Pure hydraulic oil
- Helium and water
Correct answer: Nitrogen gas and hydraulic oil
Aircraft oleo struts are typically serviced with dry nitrogen gas (to prevent moisture and oxidation) and hydraulic oil to provide proper shock absorption.
Question 5: What system provides an emergency means of extending the landing gear if the normal hydraulic system fails?
- Backup battery system
- Emergency free-fall or alternate extension system (Correct answer)
- Secondary hydraulic pump
- Manual crank only
Correct answer: Emergency free-fall or alternate extension system
Aircraft are equipped with an emergency gear extension system that allows the gear to free-fall by gravity and/or uses an alternate hydraulic or pneumatic source if the normal system fails.
Question 6: How is tire inflation pressure most accurately verified on aircraft tires?
- By visual inspection of tire sidewall bulge
- Using a calibrated tire pressure gauge (Correct answer)
- By tapping the tire with a hammer
- By checking wheel well clearance
Correct answer: Using a calibrated tire pressure gauge
A calibrated tire pressure gauge is the only accurate method to verify aircraft tire inflation pressure, which must match the aircraft manufacturer's specifications.
AMT AMT Hydraulics, Pneumatics & Landing Gear 2
What is the purpose of a shimmy damper on an aircraft nose gear?