RA-Aus BAK key terms

The angle between the wing's chord line and the relative airflow approaching it. Increasing this angle raises lift up to the stall point, beyond which airflow separates and lift drops sharply.

The direction of the air moving past the aircraft, opposite to the aircraft's flight path through the air. It is the reference used when measuring angle of attack and is unaffected by wind over the ground.

The upward aerodynamic force produced mainly by the wings as air flows around them. It depends on airspeed, air density, wing area, wing shape and angle of attack, and must balance weight in steady level flight.

The aerodynamic force opposing an aircraft's motion through the air. It has parasite components, which rise with the square of speed, and induced drag, which is greatest at low speed and high angle of attack.

The rearward component of lift created as high-pressure air under the wing spills around the tips into the low-pressure region above. It increases with angle of attack and is greatest at low airspeed.

The angle of attack at which airflow begins to separate from the wing and lift suddenly decreases. It is a fixed value for a given wing and can be reached at any airspeed, weight or attitude.

A condition in which the wing exceeds its critical angle of attack and can no longer produce enough lift. It can occur at any speed and is recovered by reducing angle of attack, typically by lowering the nose.

The ratio of the total lift being produced to the aircraft's actual weight, expressed in g. It increases in turns and pull-ups, raising the speed at which the wing reaches its critical angle of attack.

The point through which the aircraft's total weight acts. Its position must stay within the limits set in the flight manual, because moving it changes stability, control forces and stall behaviour.

The initial tendency of an aircraft, after being disturbed from a balanced condition, to return towards that condition, move further away, or stay as it is. Positive static stability makes an aircraft easier and safer to handle.

The upward angle of the wings relative to the horizontal. It gives an aircraft lateral stability, so that a wing dropping in a sideslip meets a greater angle of attack and produces more lift, rolling the aircraft level.

The speed shown on the airspeed indicator, derived from the difference between pitot (ram) pressure and static pressure. It is used for comparing performance and limiting speeds, but under-reads at altitude as air density falls.

The pressure-sensing system that supplies ram air pressure from the pitot tube and ambient pressure from the static port. It drives the airspeed indicator, altimeter and vertical speed indicator.

The altitude in the standard atmosphere at which the air density equals the actual density at the aircraft's location. High temperature, high elevation and high humidity raise it, reducing engine power, lift and propeller thrust.

The principle that where a fluid's speed increases, its pressure decreases, provided energy is conserved. It helps explain how airflow accelerating over a wing's upper surface produces lower pressure and therefore lift.

A systematic walk-around check of the aircraft before flight, covering structure, controls, fuel, oil, tyres, pitot and static openings, and documents. It is the pilot's responsibility and must be completed even when the aircraft was recently flown.

The distances needed to accelerate to flying speed and climb clear of obstacles, and to descend and stop after touchdown. Both must be calculated using current weight, wind, temperature, pressure altitude and runway surface.

The part of the wind acting across the runway, calculated from wind speed and the angle between wind and runway direction. It must not exceed the aircraft's demonstrated limit, and it affects drift on approach and touchdown.

The calculation confirming that the aircraft's loaded weight and centre of gravity lie within the limits in the flight manual. It uses empty weight, arm lengths and moments for fuel, occupants and baggage.

A turning effect calculated by multiplying a weight by its distance (arm) from a reference point. Adding moments for each loaded item and dividing the total by total weight gives the centre of gravity position.

The lowest visibility and cloud clearance permitted for flight under the visual flight rules in a given class of airspace. Pilots must remain clear of cloud and in sight of the surface where required.

The operating rules under which a pilot navigates and maintains separation from other traffic and terrain by visual reference outside the cockpit. Flight under these rules requires specified visibility and cloud clearance.

Airspace of defined dimensions within which air traffic control services are provided and, in some classes, a clearance is required before entry. Classes are designated by letters with differing requirements for clearance, radio and transponder.

An airborne radio device that replies to radar interrogations, transmitting the aircraft's identity and pressure altitude. It supports air traffic control surveillance and collision avoidance systems.

A decision to abandon an approach or landing and climb away, usually by applying full power, establishing a climb attitude and following the published or instructed procedure. It is a normal, safe option whenever an approach is unstable.

The condition of an aircraft being safe and legally fit for flight, meeting its type design and maintenance requirements. It is maintained through scheduled inspections, defect rectification and compliance with the applicable regulations.

A certification, made by an appropriately authorised person, that required maintenance has been completed and the aircraft is fit to return to service. Flight without a valid release may be illegal and unsafe.

A documented inspection performed before the first flight of a flying day, checking items such as fuel and oil levels, control freedom, tyres, structure and safety equipment. It differs from the pilot's own preflight check.

The process of recording any fault or damage found on an aircraft in the maintenance documentation and notifying the operator. Known defects must be assessed and rectified or deferred under approved procedures before further flight.

A written account submitted after an accident, serious incident or other safety-related event, describing what happened and contributing factors. Reports help authorities and operators identify hazards and prevent recurrence.

A reporting environment in which honest errors and mistakes are not punished, while reckless or deliberate breaches are still addressed. It encourages people to report safety concerns openly.

A structured set of policies, processes and practices an organisation uses to identify hazards, assess and control risk, and improve safety performance. It relies on reporting, investigation and continuous monitoring.

Any condition, object or activity with the potential to cause harm, damage or injury. Hazards are identified and their associated risks assessed and controlled before they lead to an accident.

The combination of how likely a hazardous event is and how severe its consequences would be. Risk is assessed and reduced through avoidance, mitigation or procedural controls.

The study of how human capabilities and limitations, such as fatigue, workload, perception and decision-making, affect safety and performance. Understanding them helps pilots recognise and manage error.

Calculating the fuel needed for taxi, trip, forecast winds, diversion and a required reserve, then confirming the aircraft carries at least that amount. It must be reviewed in flight as conditions change.