Aircraft Systems & Components Flashcards

How many main rotor blades does the UH-60 Black Hawk have?

Answer: 4

The UH-60 uses a four-bladed fully articulated main rotor system.

Which rotor configuration does the CH-47 Chinook use?

Answer: Tandem rotors

The CH-47 has two counter-rotating rotors mounted fore and aft in a tandem layout.

What is the primary function of a single-rotor helicopter's tail rotor?

Answer: Counteract main rotor torque and provide directional control

The tail rotor offsets the torque reaction of the main rotor and lets the pilot control yaw.

What does the swashplate assembly do?

Answer: Transmits flight control inputs from the stationary controls to the rotating rotor blades

The swashplate converts collective and cyclic inputs into blade pitch changes on the rotating system.

Which engine family powers the UH-60 Black Hawk?

Answer: T700

The UH-60 is powered by twin General Electric T700-series turboshaft engines.

Which engine powers the CH-47 Chinook?

Answer: T55

The CH-47 uses two Honeywell (Lycoming) T55 turboshaft engines.

What is the purpose of the freewheeling unit (overrunning clutch) in a helicopter drivetrain?

Answer: Allow the rotor to keep turning if the engine stops, enabling autorotation

The freewheeling unit disengages the engine from the drivetrain when engine RPM drops below rotor RPM.

Which fire-resistant hydraulic fluid is standard in most Army aircraft hydraulic systems?

Answer: MIL-PRF-83282

MIL-PRF-83282 is the synthetic, fire-resistant hydraulic fluid used in Army aircraft.

MIL-PRF-23699 is used as what type of product?

Answer: Synthetic turbine engine lubricating oil

MIL-PRF-23699 is a synthetic ester-based lubricating oil for gas turbine engines and transmissions.

What is the primary turbine fuel used in Army aircraft?

Answer: JP-8

JP-8 is the standard kerosene-based military turbine fuel.

What is the main purpose of an auxiliary power unit (APU)?

Answer: Supply electrical and pneumatic power for engine start and ground operations

The APU lets the crew start engines and run systems on the ground without external power.

Which instruments rely on the pitot-static system?

Answer: Airspeed indicator, altimeter, and vertical speed indicator

Pitot (ram) and static pressure drive the airspeed indicator, altimeter, and VSI.

What does a chip detector in a gearbox or engine oil system indicate?

Answer: Metal particles in the oil, suggesting internal wear

A magnetic chip detector collects ferrous debris and triggers a caution light when it bridges the contacts.

What is the function of an accumulator in a hydraulic system?

Answer: Store fluid under pressure and dampen pressure surges

Accumulators store pressurized fluid for peak demand and absorb pressure spikes.

On the UH-60, what is the main function of the intermediate gearbox?

Answer: Change the direction of the tail rotor drive shaft where the tail pylon angles upward

The intermediate gearbox redirects the tail rotor drive angle at the base of the tail pylon.

Why are bonding jumpers installed between aircraft structural components?

Answer: Provide an electrical path to equalize potential and dissipate static charges

Bonding gives a low-resistance path that prevents arcing, static buildup, and radio interference.

What hazard is most closely associated with nickel-cadmium aircraft batteries?

Answer: Thermal runaway

Ni-Cd batteries can overheat uncontrollably when temperature rises and internal resistance drops during charging.

In the AH-64 Apache, where is the copilot/gunner (CPG) seated?

Answer: Front seat

The AH-64 has tandem seating with the pilot in the rear and the CPG in the front.

What is commonly used to anti-ice the inlets of turboshaft engines like the T700?

Answer: Engine bleed air

Hot compressor bleed air is routed to the inlet areas to prevent ice formation.

What does the torque indicator in a helicopter primarily show?

Answer: Engine power output and drivetrain load

Torque shows how much power the engine delivers to the drivetrain, usually as a percentage.