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

A mandatory notice issued by the aviation authority requiring inspection, repair, or modification of an aircraft or component within a stated time. Compliance is compulsory and is recorded in the aircraft's maintenance documents.

A document confirming that an individual aircraft meets the design and safety standards required for flight. It remains valid only while mandatory maintenance and airworthiness directives are complied with.

The official document recording the nationality and registration marks of an aircraft and identifying its legal owner. The aircraft must carry it on board during flight.

A set of regulations allowing a pilot to operate by visual reference to the ground and horizon, subject to minimum visibility and cloud-clearance criteria. Flight under VFR requires the pilot to see and avoid other traffic.

The weather conditions of visibility and distance from cloud that must exist for flight under visual flight rules. Specific minima vary with airspace class and altitude.

An authorisation allowing a flight within controlled airspace when weather is below normal VMC minima, provided the pilot remains clear of cloud and in sight of the surface. It requires an ATC clearance.

An authorisation issued by an air traffic controller for an aircraft to proceed under specified conditions. A pilot must read back the clearance and may not deviate from it without a new authorisation.

The pilot's repetition of a controller's instruction or clearance to confirm it was correctly received and understood. Items such as route clearances, altitudes, and runway assignments must always be read back.

The assembly of blades, hub, and controls that generates lift and thrust for a helicopter. It includes the main rotor for lift and the tail rotor for anti-torque and directional control.

A mechanical assembly that transfers control inputs from the non-rotating flight controls to the rotating rotor blades. It changes blade pitch cyclically and collectively to tilt the rotor disc.

A control that changes the pitch angle of all main rotor blades equally and simultaneously. Raising it increases lift and also increases drag, requiring more engine power.

A control that varies blade pitch continuously through each revolution, tilting the rotor disc in the desired direction. Moving it forward tilts the disc forward to produce thrust.

The tail rotor or alternative device that counteracts the torque reaction of the main rotor. It also provides directional control, particularly during hover and low-speed flight.

The tendency of a helicopter to drift laterally during hover because tail rotor thrust pushes the fuselage sideways. Pilots counteract it with cyclic input, often trimming into the wind.

The additional lift produced as airflow through the rotor increases with forward speed, improving efficiency and reducing power required. It becomes effective at around 10 to 20 knots of airspeed.

The airspeed at which the rotor becomes significantly more efficient because it clears its own downwash and encounters undisturbed air. It is typically reached between 16 and 24 knots.

Flight in which the helicopter remains at a fixed point above the ground with zero airspeed. It requires more power than forward flight and demands continuous control input.

The improved lift and reduced power requirement experienced when hovering close to a surface. It results from the surface restricting the rotor downwash and is lost above roughly one rotor diameter.

The imbalance in lift between the advancing and retreating blades during forward flight. It is corrected by blade flapping and cyclic pitch variation to equalise lift across the disc.

Loss of lift on the retreating blade at high forward speed when its airspeed becomes too low. It causes vibration and pitch-up, and limits the helicopter's maximum speed.

A descent with the engine disengaged, in which upward airflow through the rotor keeps the blades turning and produces lift. The pilot manages rotor RPM with collective pitch and controls descent with cyclic.

The rotational speed of the main rotor, normally kept within a narrow approved range. Too low risks blade stall; too high risks structural damage. It is monitored on a tachometer.

A hazardous descent condition in which the rotor recirculates its own downwash, causing loss of lift and heavy vibration. Recovery requires forward cyclic to gain airspeed out of the condition.

A power-settling descent occurring at low airspeed and high power with a significant rate of descent, where the rotor cannot arrest the sink. Adding collective worsens it; forward airspeed is the remedy.

The altitude at which the aircraft would perform as if at that height in a standard atmosphere. High temperature, humidity, and elevation raise density altitude and reduce performance.

The greatest weight at which the helicopter is permitted to begin take-off. Exceeding it degrades performance and climb capability and may invalidate the aircraft's certification.

The process of ensuring the loaded aircraft's total weight and centre of gravity stay within approved limits. An out-of-limits centre of gravity can make the helicopter uncontrollable.

The point at which the aircraft's total weight is considered to act. Its position must remain within a specified forward and aft range for safe controllability.

The highest altitude at which the helicopter can maintain a specified climb rate under given conditions. It decreases with higher temperature and weight.

A condition in which body tissues receive insufficient oxygen, causing impaired judgement, euphoria, and loss of consciousness. It can occur at relatively low altitudes in unpressurised helicopters.

Rapid or deep breathing that reduces carbon dioxide in the blood, causing dizziness, tingling, and anxiety. Its symptoms resemble hypoxia, but the treatment is to slow the breathing rate.

A false perception of the aircraft's position or motion caused by misleading sensory inputs, especially without visual reference. Recovery depends on trusting flight instruments rather than sensations.

A misleading sensation of motion arising from the inner ear, such as the leans or somatogravic illusion. It is most dangerous when visual references are lost.

The altimeter setting that makes the altimeter indicate elevation above mean sea level at the reporting station. It is used for en-route and approach altitude reference.

The altimeter setting that makes the altimeter read height above a specified reference point, usually the aerodrome. It is used for traffic pattern and landing operations.

The altitude above which pilots set the standard pressure setting of 1013.25 hPa on the altimeter. Below it, the local QNH is used.

An altitude expressed in hundreds of feet referenced to the standard pressure setting of 1013.25 hPa. Flight levels are used above the transition altitude.

A sudden change in wind speed or direction over a short distance, horizontally or vertically. It can cause abrupt airspeed changes and is hazardous during approach and hover.

A localized, intense downdraft that spreads outward on reaching the ground. It produces severe wind shear and can cause sudden loss of airspeed and altitude close to the surface.

A navigation method of estimating position from the last known point using heading, airspeed, and elapsed time, corrected for wind. It is the basis for flight planning calculations.

The direction in which the aircraft's nose points, measured clockwise from north. It differs from track because of drift caused by wind.

The actual path of the aircraft over the ground, measured clockwise from north. Wind causes the track to differ from the heading.

The lateral displacement of an aircraft from its intended path caused by wind. Pilots correct for it by applying a wind correction angle.

A document certifying that specified maintenance has been completed and the aircraft is fit for return to service. It must be signed by authorised personnel.

A systematic check of the helicopter's condition, controls, and fluid levels before flight. It is the pilot's responsibility and must be completed before every flight.

A set of standard words, such as Alpha and Bravo, used to spell letters clearly over the radio. It reduces misunderstanding caused by noise or interference.

A radio receiver circuit that mutes background noise when no usable signal is present. Correct setting prevents distracting static while allowing clear reception.