Engineer Aircraft flashcards
Engineer Aircraft · 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 limit load without permanent deformation, and ultimate load is 1.5 times limit load.
- Shear flow formula
- For a thin-walled closed section in torsion, shear flow q equals torque T divided by twice the enclosed median-line area A, so q = T/(2A).
- Fail-safe design
- A design philosophy in which redundant load paths and crack-stopping features ensure that a single failure or discrete damage does not cause catastrophic structural loss.
- Hoop stress
- In a pressurized cylinder, circumferential stress equals internal pressure times radius divided by wall thickness, which is twice the longitudinal stress.
- Brayton cycle
- The thermodynamic cycle of a gas turbine: compression, constant-pressure heat addition, expansion, and heat rejection. Efficiency rises with pressure ratio and turbine inlet temperature.
- Engine pressure ratio
- The ratio of turbine discharge total pressure to compressor inlet total pressure. It is used as a thrust-setting parameter on many turbofan engines.
- Compressor surge
- A full-annulus breakdown of compressor flow that causes a loud bang and thrust loss. It is countered by bleed valves, variable stator vanes, and careful acceleration scheduling.
- Specific fuel consumption
- Fuel flow per unit of thrust produced. Lower values indicate better efficiency, achieved through higher bypass ratio and higher overall pressure ratio.
- ARINC 429 bus
- A unidirectional digital data bus using 32-bit words over twisted pairs. It is widely used for avionics communication and supports one transmitter with multiple receivers.
- Generator control unit
- A unit that regulates generator voltage and protects against overvoltage, undervoltage, overfrequency, and differential faults, and controls paralleling of generators.
- Calibrated airspeed
- Indicated airspeed corrected for position and instrument error. It approximates true airspeed at sea level standard conditions and is used for many performance calculations.
- Bonding resistance
- The electrical resistance between bonded aircraft parts. A low value ensures a safe return path for fault current and effective lightning and electromagnetic interference protection.
- Hydraulic relief valve
- A valve that opens at a set pressure to protect the hydraulic system from overpressure, returning excess fluid to the reservoir or return line.
- Unusable fuel
- The fuel remaining in tanks that cannot be delivered to the engine under the most adverse operating conditions. It is excluded from usable fuel calculations.
- Bleed air precooler
- A heat exchanger that cools engine bleed air before it enters the pneumatic manifold, limiting duct temperature and protecting downstream components and structures.
- Beta ratio
- A filter rating expressing the ratio of particles upstream to downstream of a given size. A higher beta ratio indicates better filtration efficiency at that size.
- Fly-by-wire
- A flight control system in which pilot inputs are converted to electrical signals and processed by computers that command hydraulic actuators, enabling envelope protection.
- Shimmy damper
- A device that dampens nosewheel oscillation by adding hydraulic or friction resistance to steering motion, preventing self-excited shimmy during takeoff and landing rolls.
- Anti-skid system
- A system that modulates brake pressure to keep wheel slip near the optimum, preventing wheel lockup and maintaining directional control and braking effectiveness.
- Squat switch
- A weight-on-wheels sensor that signals the aircraft is on the ground, enabling gear retraction interlocks and controlling pressurization and anti-skid logic.
- MSG-3 process
- A scheduled maintenance development method that selects tasks based on failure consequences, covering lubrication, inspection, and functional checks for significant items.
- Borescope inspection
- An internal visual inspection of engine compressor and turbine sections using a flexible or rigid scope, performed without engine disassembly and compared with manual limits.
- Certificate of release to service
- A document issued after maintenance certifying that the work was performed in accordance with approved data and that the aircraft is airworthy for the intended flight.
- Lockwire
- A safetying method using twisted wire through drilled bolt heads to prevent loosening. Correct twist direction and tension are required for effective locking.
- Airworthiness Directive
- A mandatory directive issued by an airworthiness authority requiring inspection, modification, or operational limitation within a stated compliance time to correct an unsafe condition.
- Supplemental type certificate
- An approval for a major modification to a type-certified product that is not covered by the original type certificate, issued after demonstrating compliance with applicable requirements.
- Minimum equipment list
- An approved document allowing dispatch with specified equipment inoperative, subject to conditions and placards, and never less restrictive than the master minimum equipment list.
- SHEL model
- A human factors model describing interfaces between software, hardware, environment, and liveware. Mismatches at these interfaces are sources of human error.
- Swiss cheese model
- An accident causation model in which aligned holes in multiple defensive layers allow an accident. Safety management strengthens defenses rather than blaming individuals.
- Just culture
- A safety culture that distinguishes human error from at-risk and reckless behavior, encouraging reporting while retaining disciplinary action for reckless conduct.
- Dye penetrant inspection
- A non-destructive test that detects surface-breaking defects in nonporous materials by applying a penetrant, removing excess, and developing a visible indication.
- Eddy current inspection
- A non-destructive test that detects surface and near-surface cracks in conductive materials by inducing eddy currents and monitoring changes in the electromagnetic field.