CAA NZ AME Licence Exam - Rotorcraft flashcards

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

Fully articulated rotor head

A rotor head with separate flapping, lead-lag and pitch-change hinges for each blade. It allows independent blade motion, suits three or more blades, and requires dampers to control lead-lag oscillation.

Teetering rotor head

A two-blade semi-rigid rotor head with a single underslung flapping hinge that lets the blades see-saw. Coning loads are carried through the hub and mast, so blade flapping is limited by hub stops.

Ground resonance

Self-excited oscillation where rotor lead-lag motion couples with airframe motion on the landing gear. It is prevented by serviceable dampers and oleos; recovery is immediate liftoff or throttle reduction.

Coning angle

The upward angle a blade makes with the rotor disc plane due to lift. It increases with thrust and is relieved by flapping hinges or composite flexure, reducing root bending stress.

Pitch-change spider

A non-rotating sleeve that moves along the tail rotor shaft to change blade pitch through pitch links. It is connected to the pilot pedals and the yaw control system.

Static and dynamic balance

Static balance corrects chordwise centre of gravity using weights; dynamic balance corrects spanwise and chordwise imbalance causing vibration. Both are done per the maintenance manual after blade or hub work.

Blade tracking

Adjustment of blade tip paths so they follow the same plane. Out-of-track blades cause once-per-revolution vibration; tracking is done by flag or electronic equipment and corrected with pitch links or tabs.

Free-turbine engine

A turboshaft where the gas generator and power turbine are on separate shafts. The power turbine drives the rotor through a freewheel unit, so the rotor can autorotate if the engine stops.

Freewheel unit

A one-way sprag or roller clutch that transmits engine drive to the rotor but releases when rotor speed exceeds engine speed. It enables autorotation and is checked during run-up.

N1 and N2

N1 is gas generator (compressor) speed; N2 is power turbine or rotor speed. Both are displayed as percentages and have limits in the flight and engine manuals.

Turbine outlet temperature

TOT (or T4/T5) is the gas temperature measured at the turbine outlet. It is a primary engine limit; exceeding it, especially in a hot start, requires fuel shutoff and inspection.

Hot start

A start where turbine temperature exceeds the limit, usually from too much fuel or slow N1. The procedure is to shut off fuel and motoring, then inspect per the engine manual.

Fuel control unit

The hydro-mechanical unit that meters fuel using N1, compressor discharge pressure, TOT and collective pitch. It is trimmed by the electronic engine control, which also handles starting and overspeed protection.

Chip detector

A magnetic plug in the engine or gearbox oil system that collects ferrous particles. Fuzz is normal; metal flakes or chunks require inspection and oil system checks per the manual.

Autorotation

A flight condition where the main rotor is driven by upward airflow instead of the engine. The freewheel releases, and rotor RPM is controlled by collective pitch and airspeed.

Loadmeter vs ammeter

A loadmeter shows alternator or generator output current; an ammeter shows battery charge or discharge. A discharge in flight indicates alternator failure and requires load shedding.

Bonding and grounding

Low-resistance connections between metallic parts and the airframe return, providing a path for static and fault current. Bonding resistance is checked per the maintenance manual after structural or electrical work.

Magnetic compass swing

A calibration of the compass that determines deviation and produces a deviation card. It is required after installing magnetic or electrical equipment, welding, or major structural change.

Alternate static source

A valve that supplies cabin pressure to the static instruments when the external static ports are blocked. It causes airspeed, altimeter and VSI errors, so the flight manual procedure is used.

Low rotor RPM warning

A horn or light that alerts the pilot when rotor RPM falls below a set value. It is tested before flight and is essential for recognising an impending power or rotor failure.

Emergency bus

A bus that powers essential instruments and radios when the main electrical supply fails. Its battery endurance and function are checked during scheduled maintenance and pre-flight checks.

Antenna VSWR check

A measurement of reflected power from an antenna installation. A high VSWR indicates a poor connection or damaged antenna, so it is checked after installation or repair.

Certificate of release to service

A certification issued by an appropriately rated LAME after maintenance, stating the work done, references used and any limitations. It releases the aircraft to service.

Airworthiness directive

A mandatory instruction issued by the CAA to correct an unsafe condition. Compliance is required within the stated time or usage limit and is recorded in the aircraft records.

Service bulletin

A manufacturer's recommended instruction, usually not mandatory unless made so by an airworthiness directive or the approved maintenance programme. Compliance is recorded when accomplished.

Dirty Dozen

Twelve human-factor precursors to maintenance error: fatigue, complacency, distraction, pressure, stress, communication, resources, teamwork, knowledge, assertiveness, norms and awareness. They guide error analysis and prevention.

SHELL model

A human-factors framework showing the interaction of Software, Hardware, Environment and Liveware (people). It is used to analyse maintenance errors and design defences.

Maintenance error reporting

A non-punitive report of an error or occurrence to the operator's safety management system and the CAA. It supports investigation and prevention rather than blame.

Shift handover

A recorded transfer of open defects, deferred items, parts on order and work in progress between shifts. Verbal handover alone is insufficient for traceability.

MEL and CDL

The Minimum Equipment List and Configuration Deviation List define allowable deferred defects and missing items for dispatch. They are approved documents referenced in the operations manual.

Tool control

A system of shadow boards, tool counts and sign-out records that ensures no tool is left in an aircraft. It prevents foreign object damage and is a standard maintenance practice.

Fuel sampling

Draining fuel from sumps until it is clear and bright to detect water and sediment. Refuelling requires bonding and grounding to prevent static ignition.