ATPL Aero & Systems flashcards
ATPL Aero & Systems · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Limit load
- The maximum load expected in normal service; the structure must withstand it without permanent deformation and ultimate load is 1.5 times limit load.
- Load factor
- The ratio of lift to weight; in a level banked turn it equals one divided by the cosine of the bank angle.
- Design manoeuvring speed VA
- The speed at which full control deflection produces the limit load factor; below VA the wing stalls before the structure reaches its limit load.
- Fail-safe structure
- A design in which the failure of one load path is carried by remaining structure until the fault is detected, avoiding catastrophic failure.
- Pascal's law
- Pressure applied to a confined fluid is transmitted undiminished in all directions, so force equals pressure multiplied by piston area.
- Hydraulic accumulator
- A gas-charged chamber that stores hydraulic energy, damps pressure surges and supplies reserve pressure for emergency operation.
- Pressure relief valve
- A valve that opens to limit system pressure and protect components from overpressure; it is a safety device, not a normal pressure regulator.
- Cabin pressure differential
- The difference between cabin pressure and ambient pressure; it is limited by the structural design differential of the fuselage.
- Outflow valve
- A valve that regulates the rate at which cabin air leaves the aircraft, thereby controlling cabin pressure and cabin altitude.
- Air-cycle machine
- A cooling unit that compresses bleed air, cools it in a heat exchanger and expands it through a turbine to produce cold air.
- Generator frequency
- The frequency of an AC generator equals the number of poles multiplied by rotational speed in rpm, divided by 120.
- Bus tie
- A switchable connection between electrical buses that allows power to be shared or transferred between generators or to essential buses.
- Reverse-current cut-out
- A device that disconnects a DC generator from the bus when current flows back into the generator, preventing damage.
- Yaw damper
- An automatic system that feeds yaw rate back to the rudder to suppress Dutch roll and improve ride comfort.
- Fly-by-wire
- A control system that replaces mechanical linkage with electrical signals and computers, enabling envelope protection and load alleviation.
- Servo tab
- A small tab that moves the main control surface by aerodynamic force, reducing the control force required from the pilot.
- Anti-skid system
- A system that modulates brake pressure to prevent wheel lock, preserving friction and directional control during braking.
- Shimmy damper
- A device that dampens rapid oscillation of the nose wheel about its steering axis, preventing shimmy during take-off and landing.
- Brake energy
- The kinetic energy absorbed during braking equals half the mass multiplied by the square of the speed, so speed dominates brake heating.
- Fuel boost pump
- A pump that supplies positive fuel pressure to the engine-driven pump and provides backup if the engine pump fails.
- Fuel tank venting
- Tanks are vented to atmosphere so that fuel can flow and pressure does not build up or fall below ambient.
- Fuel crossfeed
- A valve arrangement that allows fuel to be supplied from one tank to either engine, correcting imbalance and extending range.
- Pitot heater
- An electrical heater that prevents ice blockage of the pitot tube, which would otherwise cause erroneous airspeed indications.
- Fire handle
- A cockpit control that closes the fuel, bleed and hydraulic shut-off valves to the affected engine and arms the extinguisher.
- De-ice boots
- Inflatable rubber boots on the leading edge that cyclically inflate to break ice off the protected surface.
- Detonation
- Uncontrolled rapid combustion of the fuel-air mixture that causes high cylinder pressure and temperature and can damage the engine.
- Constant-speed propeller
- A propeller whose governor varies blade pitch to hold a selected rpm as engine power and airspeed change.
- Carburettor icing
- Ice formation in the carburettor caused by venturi cooling and fuel evaporation, possible at ambient temperatures well above freezing.
- Specific fuel consumption
- The fuel flow required per unit of thrust; a lower value indicates a more efficient engine.
- Bypass ratio
- The mass flow through the fan bypass duct divided by the mass flow through the engine core.
- Compressor surge
- An unstable compressor condition with reverse flow and loud bangs, caused by blade stall and countered by bleed valves.
- Exhaust gas temperature
- A monitored turbine temperature that indicates engine load and is limited to protect turbine blades from overheating.