Airframe 7

Hydraulic pump chattering during run-up indicates: Low accumulator pressure. Air in pump inlet line. Worn O-rings.

Purpose of a surge chamber: Store hydraulic fluid. Absorb pressure shock. Cool hydraulic fluid.

Purpose of a hydraulic accumulator: Filter fluid. Maintain system pressure. Prevent overtravel.

Snubbers on hydraulic gauges prevent: Overpressure. Rapid needle fluctuations. Internal leakage.

How to check landing gear strut fluid level: Inflate strut first. Deflate and fill to filler plug. Remove strut.

Seals used with mineral-oil hydraulic fluid: Leather. Neoprene or synthetic. Cork.

Cabin pressurization modes: Automatic, manual, emergency. Isobaric, differential, unpressurized. Ram-air, bleed-air, recirculation.

In isobaric mode, cabin pressure is controlled by: Dump valve. Regulator bellows. Turbine outlet door.

In differential mode, reference pressure is vented by: Safety valve. Differential metering valve. Flow control valve.

Final cooling stage in an air-cycle system: Heat exchanger. Expansion turbine. Ram-air inlet.

If cabin rate of climb is too high: Pressurization stops. Outflow valve closes faster. Safety valve opens.

Purpose of evacuating a freon system: Add lubrication. Remove moisture. Reduce temperature.

How is a helicopter considered regarding stability?. Fully stable. Statically stable, dynamically unstable. Statically unstable, dynamically stable.

Blade rotational speed is associated with: Drag. Centrifugal force. Induced flow.

Blade coning is caused by: Blade twist. Lift vs centrifugal force. Drag vs thrust.

Which blade stalls first?. Advancing blade. Retreating blade. Tail rotor blade.

Dissymmetry of lift is corrected by: Feathering. Blade flapping. Collective pitch.

Coriolis effect is associated with: Vertical blade vibration. Lead-lag motion. Tail rotor drift.

Fully articulated rotors compensate Coriolis with: Underslinging. Lead-lag hinges. Blade sweep.

Semi-rigid rotors compensate Coriolis with: Lead-lag hinges. Underslinging. Counterweights.

Purpose of the flapping hinge: Increase blade twist. Allow advancing blade to flap up. Reduce vibration.

Translational lift occurs at: 5–10 mph. 15–20 mph. 30–40 mph.

Transverse flow effect: Lift increases forward of disc. More downwash aft than forward. Downwash equal across disc.

Airflow direction during autorotation: Downward. Upward. Sideways.

If the freewheeling unit seizes: Engine drives the rotor. Rotor drives the engine. Tail rotor disconnects.

Tail rotor dynamic balance is adjusted by: Trim tab. Adding or removing weights. Blade painting.

Tail rotor dissymmetry in forward flight is reduced by: Stabilator alone. Delta hinge + vertical fin. Pedal adjustment.

European helicopters on takeoff require: Left pedal. Right pedal. No pedals.

Torque effect follows: Bernoulli’s law. Newton’s 3rd law. Coriolis effect.

Tail rotor shaft runout is measured with: Micrometer. Dial indicator. Torque wrench.

What unloads the rotor during startup?. Governor. Clutch. Freewheeling unit.

Why place propeller in low pitch for takeoff?. Less drag. Maximum horsepower. Reduce RPM.

How to repair a dent in a steel propeller?. Heat and reshape. File smooth and polish. Weld filler.

How to track a wooden prop blade?. Add weight to tip. Install shims. Bend the blade.

Final metal prop balancing is done by: Adding lead wool. Filing the tips. Painting the blade.

Wooden propeller balancing is done by: Adding solder to the tip. Filing the leading edge. Painting the blade.