Part-66 Module 1 flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Ohm's law

Voltage equals current multiplied by resistance (V = IR). Power dissipated equals voltage times current, and can also be written as I²R or V²/R.

Pythagoras theorem

In a right-angled triangle, the square of the hypotenuse equals the sum of the squares of the other two sides. Used for vector and distance calculations.

Newton's second law

The acceleration of a body is directly proportional to the net force acting on it and inversely proportional to its mass, expressed as F = ma.

Series resistance

In a series circuit, individual resistances add directly to give total resistance, the current is the same throughout, and voltages sum to the supply voltage.

Parallel resistance

In a parallel circuit, the reciprocal of total resistance equals the sum of the reciprocals of individual resistances, and voltage is the same across each branch.

Diode forward voltage

A silicon diode begins to conduct when forward biased above about 0.7 volts; a germanium diode conducts above about 0.3 volts.

Inverting amplifier gain

For an operational amplifier with input resistor R_in and feedback resistor R_f, the voltage gain equals minus R_f divided by R_in.

Two's complement

A method of representing signed binary numbers in which the most significant bit is the sign bit, and negation is achieved by inverting all bits and adding one.

De Morgan's theorems

NOT of (A AND B) equals (NOT A) OR (NOT B); NOT of (A OR B) equals (NOT A) AND (NOT B). Used to simplify logic circuits.

ARINC 429

A point-to-point serial digital data bus used on many transport aircraft, transmitting 32-bit words from one transmitter to one or more receivers.

Temper designation T

In aluminium alloy numbering, the T prefix indicates solution heat treatment followed by ageing, producing higher strength than the annealed O condition.

Rivet grip length

The grip length of a rivet is the total thickness of the material it joins. It must match the combined thickness of the parts before setting.

Galvanic corrosion

Corrosion that occurs when two dissimilar metals are in electrical contact in the presence of an electrolyte; the less noble metal becomes anodic and corrodes.

Lockwire direction

Safety wire must be installed so that the twist pulls the fastener in the tightening direction, preventing it from loosening in service.

Certificate of Release to Service

A document certifying that maintenance has been completed in accordance with approved data and that the aircraft or component is airworthy for release to service.

Airworthiness Directive

A mandatory instruction issued by an airworthiness authority requiring specific action on an aircraft or component within a stated timeframe to correct an unsafe condition.

Bernoulli's principle

In steady streamline flow, an increase in fluid velocity is accompanied by a decrease in static pressure, which explains the pressure distribution over an aerofoil.

Critical angle of attack

The angle of attack at which the wing produces maximum lift; beyond it the airflow separates and the wing stalls regardless of airspeed.

Induced drag

Drag caused by the generation of lift, associated with wingtip vortices; it increases with lift coefficient and decreases as airspeed increases.

SHELL model

A human factors model describing interactions between software, hardware, environment and liveware, with the central liveware representing the human operator.

Hypoxia symptoms

Symptoms of oxygen deficiency include euphoria, impaired judgement, headache, cyanosis and loss of consciousness; onset is faster at higher altitudes.

Swiss cheese model

A model of accident causation in which latent conditions and active failures align through successive layers of defence, allowing an accident to occur.

Oleo strut servicing

A landing gear oleo strut is serviced with hydraulic fluid to the correct level and nitrogen to the specified pressure to absorb landing loads.

Outflow valve function

The outflow valve modulates the rate at which cabin air leaves the aircraft, thereby controlling cabin altitude and differential pressure in a pressurised aircraft.

Primary flight controls

Ailerons control roll, elevators control pitch and the rudder controls yaw; these are the principal controls for manoeuvring the aircraft about its axes.

Translational lift

The additional lift gained as a helicopter moves forward out of its own downwash, typically becoming effective above about ten to twenty knots.

Dissymmetry of lift

The unequal lift produced by advancing and retreating blades in forward flight, equalised by blade flapping and cyclic pitch changes.

Autorotation

A helicopter descent in which the rotor is driven by upward airflow rather than engine power, with rotor RPM controlled by collective pitch.

Torque wrench calibration

A torque wrench must be calibrated at intervals set by the approved maintenance organisation, with records retained to demonstrate continued accuracy.

Functional versus operational check

A functional check verifies that a system operates within specified limits using measurement; an operational check confirms it functions as intended without measurement.

Cosine rule

In any triangle, the square of one side equals the sum of the squares of the other two sides minus twice their product times the cosine of the included angle.

Mach number

The ratio of true airspeed to the local speed of sound; compressibility effects become significant above the critical Mach number of the aerofoil.