ANAC Private Pilot Helicopter (PPH) (ANAC) key terms

Rules under which a pilot may operate an aircraft while remaining clear of clouds and maintaining specified visibility, using outside visual reference for navigation and separation from obstacles and other traffic.

A clearance allowing flight within a control zone in weather below normal VFR minima, provided the pilot stays clear of clouds and obtains an ATC clearance before entering or operating within that zone.

Airspace of defined dimensions within which air traffic control service is provided to flights in accordance with airspace classification, requiring clearances for entry and ongoing compliance with ATC instructions.

An authorisation issued by ATC for an aircraft to proceed under specified conditions, which the pilot must read back correctly and comply with unless an emergency requires deviation.

The pilot's repetition to ATC of safety-related clearance elements such as route, level, heading, and frequency, confirming that the instruction was correctly received and understood before it is acted upon.

A mandatory notice issued by the aviation authority requiring inspection, modification, or repair of a specific aircraft type, engine, or component to correct an unsafe condition affecting continued airworthiness.

A document confirming that an individual aircraft conforms to its approved type design and is considered safe to operate within the limitations and conditions stated on the certificate.

A certification signed after maintenance work confirming that the aircraft or component has been maintained in accordance with approved procedures and is fit for return to service.

A condition where the rotor blade tips flapping upward strike the rotor mast or hub stops, caused by low rotor RPM combined with high blade flapping angles, producing vibration and possible structural damage.

Upward and downward movement of a rotor blade about its horizontal hinge, allowing the advancing blade to rise and the retreating blade to descend, thereby balancing lift across the rotor disc.

The unequal lift produced on advancing and retreating sides of a rotor disc in forward flight because of different relative airflow speeds, compensated by blade flapping and feathering.

Loss of lift on the retreating blade at high forward speed or high disc loading, producing pitch-up, vibration, and roll toward the retreating side, requiring immediate reduction of speed and load.

The rotor blade moving rearward relative to the aircraft's flight path, experiencing lower relative airflow and therefore requiring a greater angle of attack to generate lift equal to the advancing side.

The additional lift gained as horizontal airflow through the rotor disc increases with forward speed, improving efficiency and reducing induced power requirements compared with hovering flight.

The stage of forward flight, typically around 10 to 15 knots, where the rotor becomes significantly more efficient, vibration reduces, and climb performance improves noticeably.

Improved hover performance occurring near the surface, where the downwash is restricted and recirculation is reduced, allowing the same weight to be supported with less power.

The maximum altitude at which a helicopter can maintain a hover, in or out of ground effect, under specified weight, temperature, and pressure conditions.

Pressure altitude corrected for non-standard temperature, representing the altitude the aircraft performance feels; high density altitude reduces lift, engine power, and climb capability.

The altitude indicated when the altimeter subscale is set to the standard pressure of 1013.25 hPa, used as the basis for performance calculations and flight levels.

The local pressure value set on the altimeter subscale so that the instrument indicates height above a chosen reference, such as aerodrome elevation or mean sea level.

The altitude above which pilots set the altimeter to standard pressure and express vertical position as flight levels, and below which local pressure settings are used.

The calculation ensuring that aircraft weight and the position of its centre of gravity remain within approved limits for the planned flight, preserving controllability and performance.

The point at which the aircraft's total weight is considered to act; it must stay within a defined forward and aft range to ensure adequate control authority and stability.

The difference between maximum permissible take-off mass and the empty mass of the aircraft, comprising crew, passengers, baggage, and usable fuel.

A pilot's mistaken perception of position, attitude, or motion relative to the earth, often caused by conflicting vestibular and visual inputs in degraded visual conditions.

False sensations of rotation or motion arising from the inner ear's semicircular canals and otolith organs, particularly when head movements occur during sustained turns or accelerations.

A false sensation of pitching up during acceleration or pitching down during deceleration, caused by linear acceleration stimulating the otolith organs, which can mislead a pilot in low visibility.

A condition in which body tissues receive insufficient oxygen, causing impaired judgement, reduced night vision, and loss of consciousness at altitude, with helicopter crews affected mainly at higher cabin altitudes.

Abnormally rapid or deep breathing that lowers blood carbon dioxide, producing dizziness, tingling, and confusion that can mimic hypoxia and impair a pilot's ability to control the aircraft.

A state of reduced physical and mental capability resulting from prolonged activity, insufficient rest, or disrupted circadian rhythm, degrading reaction time, attention, and decision-making in flight.

The effective use of all available resources, including crew, equipment, and information, through communication, leadership, and workload management to improve safety and decision quality.

A rotor speed below the normal operating range that reduces lift and control authority, potentially leading to blade stall, mast bumping, and loss of control if not corrected promptly.

A descending flight condition in which the rotor turns without engine power, driven by upward airflow through the disc, allowing a controlled landing after an engine failure.

Loss of engine power in flight, requiring the pilot to lower collective, maintain rotor RPM, select a landing area, and complete an autorotative approach and touchdown.

A written list of immediate actions for specific failures, memorised for time-critical items and consulted for follow-up steps to ensure a disciplined and complete response.

A change of wind speed or direction over a short distance, often near thunderstorms or fronts, capable of causing sudden airspeed loss and loss of control at low altitude.

A small, intense downdraft from a thunderstorm that spreads out at the surface, producing severe and rapidly changing wind that can cause abrupt loss of airspeed and lift.

A cumulonimbus cloud producing lightning, heavy rain, hail, strong gusts, and turbulence, all of which present serious hazards to helicopters, especially in the mature stage.

An instrument that measures atmospheric pressure and displays it as altitude, requiring the correct subscale setting to indicate height above the chosen reference datum.