Oman CAA IR(H) key terms

A specified altitude in a precision or APV approach at which a missed approach must be initiated if the required visual reference has not been established. It is referenced to mean sea level.

A specified height above the aerodrome elevation, or above the threshold elevation for precision approaches, below which descent is not permitted unless the required visual reference is in sight.

The point in an instrument approach procedure at which a missed approach must be initiated if the required visual reference to continue the approach has not been established.

A published sequence of manoeuvres to be flown after a discontinued instrument approach, designed to bring the aircraft from the MAPt to a position from which another approach or a diversion can be made safely.

The fix at the beginning of the initial segment of an instrument approach procedure, where the aircraft enters the published approach routing before reaching the intermediate segment.

The fix identifying the point where the aircraft is established on the final approach course and begins descent to the DA or MDH, marking the start of the final approach segment.

A published manoeuvre that reverses the direction of flight so the aircraft can establish itself inbound on the approach course, normally flown within a defined protected area.

Any manoeuvre, such as a procedure turn, holding pattern or teardrop, used to reverse direction and establish the aircraft on the inbound approach or airway track.

A predetermined manoeuvre keeping an aircraft within a specified airspace while awaiting further clearance, consisting of inbound and outbound legs joined by two turns.

The measured or calculated time on the inbound leg of a holding pattern, used to adjust the outbound leg so the inbound leg is flown in the specified time, corrected for wind.

The angle applied to a heading to compensate for wind so the aircraft tracks the desired course, usually expressed as a heading different from the required track.

The actual path of the aircraft over the ground, expressed as a direction, which may differ from the intended track when wind or heading errors exist.

A vector diagram relating true airspeed, wind velocity and ground speed with track and heading, used to calculate heading and groundspeed for a planned leg.

The lowest published altitude for an airway or route segment that meets obstacle clearance and navigation signal coverage requirements for the whole segment.

The lowest altitude on an airway segment that provides required obstacle clearance, though it may not guarantee navigation signal coverage for the entire segment.

The lowest altitude used in an instrument approach procedure that ensures the required obstacle clearance margin above all relevant obstacles in the approach area.

The altitude at or below which the aircraft's vertical position is expressed in altitude above mean sea level, above which it is expressed as flight level.

The lowest flight level available for use above the transition altitude, at which or above which vertical position is expressed as a flight level referenced to standard pressure.

The altimeter sub-scale setting that, when set on the ground at aerodrome elevation, causes the altimeter to indicate that elevation above mean sea level.

The standard altimeter setting of 1013.25 hectopascals used above the transition level so all aircraft share a common vertical reference.

An airspace designation permitting 1000-foot vertical separation between suitably equipped aircraft between specified flight levels, requiring approved altimetry and autopilot systems.

A navigation specification stating the onboard performance monitoring and alerting required, and the lateral navigation accuracy in nautical miles to be maintained for at least 95 percent of flight time.

A method of navigation permitting aircraft operation on any desired flight path within the coverage of navigation aids or self-contained aids, rather than being constrained to fly directly to or from them.

A satellite-based system providing worldwide position and time information, used by aircraft receivers for en-route navigation and instrument approach guidance.

A receiver function that checks the consistency of satellite signals to detect and, in some cases, exclude faulty signals, ensuring the integrity needed for the intended navigation operation.

A specified geographical location used to define an area navigation route or the flight path of an aircraft employing area navigation.

An onboard computer system that integrates navigation sensors and a database to provide flight planning, guidance, performance calculation and lateral and vertical navigation.

An aircraft computer that calculates airspeed, altitude, altitude trend and other parameters from pitot and static pressure inputs and supplies them to instruments and systems.

The aircraft system of pressure probes and static ports that supplies total and static pressure to the airspeed indicator, altimeter and vertical speed indicator.

A blockage of the pitot probe, often by ice or debris, that traps pressure and causes airspeed indications to behave like an altimeter, rising in climb and falling in descent.

An electrical heating element in the pitot probe that prevents or clears ice accumulation, protecting airspeed indications when flying in visible moisture at low temperatures.

The accumulation of ice on aircraft surfaces in flight, which increases weight and drag, reduces lift and can degrade control and instrument readings.

The lowest altitude in the atmosphere at which the air temperature is zero degrees Celsius, above which icing conditions may be encountered in cloud or precipitation.

Ice formation in a piston engine carburettor caused by fuel vaporisation and pressure drop cooling, which can occur at outside air temperatures well above freezing.

A pilot's incorrect perception of the aircraft's position, attitude or motion relative to the earth, often caused by misleading vestibular and visual sensations in the absence of outside visual references.

A false sensation of pitch caused by linear acceleration or deceleration, such as feeling a pitch-up during acceleration, which can lead a pilot to push forward in error.

The inner-ear organs sensing rotation and linear acceleration, which provide motion cues but can produce illusions when visual references are absent in instrument conditions.

The organised pattern of eye movements a pilot uses to cross-check flight instruments, alternating attitude, performance and navigation indications to detect and correct deviations promptly.

A gyroscopic or electronic instrument displaying the aircraft's pitch and roll relative to the horizon, forming the primary reference for attitude control in instrument flight.

A gyroscopic or electronic instrument showing the aircraft's heading, used with the attitude indicator and turn indications to control direction in instrument flight.

Meteorological conditions expressed in terms of visibility, distance from cloud and ceiling that are less than the specified minima for visual meteorological conditions.

The set of rules governing flight under which the pilot must comply with instrument procedures, including navigation, communication and separation requirements, regardless of weather.

An authorisation from air traffic control for an aircraft to proceed under instrument flight rules within controlled airspace, specifying route, altitude and any restrictions.

The pilot's repetition to air traffic control of a clearance or instruction to confirm it has been correctly received and understood, required for safety-related items.

A radio message from the aircraft to air traffic control stating its position, time, altitude and next estimated reporting point, used where surveillance coverage does not exist.

The additional lift a helicopter gains as it accelerates from the hover into effective translational lift, where the rotor meets undisturbed air and efficiency improves.

The condition, typically reached around 15 to 20 knots of airspeed, at which the rotor disc escapes its own downwash and lift and control improve markedly.

A stall on the retreating rotor blade at high forward speed or high load, where low relative airflow and high angle of attack cause lift loss and pitch-up tendency.

The unequal lift produced on advancing and retreating sides of a rotor in forward flight, balanced by blade flapping and cyclic feathering to keep the disc level.

A condition in which the helicopter descends into its own downwash, causing recirculating airflow, loss of lift and high descent rate despite increased power.

A rotorcraft flight condition in which the rotor is driven by upward airflow during descent rather than by engine power, allowing a controlled landing after power loss.

The control that changes the pitch of all rotor blades simultaneously, increasing or decreasing total rotor thrust and determining the helicopter's power requirement.

The portion of the approach lighting or runway environment that must be clearly visible to the pilot before descending below the DA or MDH.

A helicopter instrument approach where the final segment ends at a point in space rather than a runway, from which the pilot proceeds visually to the landing area.

An instrument approach procedure designed for a heliport or landing site, often using steeper descent angles and lower speeds, requiring specific helicopter performance and equipment.

Airspace of defined dimensions within which air traffic control service is provided to IFR and, where specified, VFR flights in accordance with airspace classification.

The service provided to prevent collisions between aircraft and between aircraft and obstructions, and to expedite and maintain an orderly flow of traffic.

A prohibition on commencing or continuing an instrument approach when reported weather is below specified minima or when aerodrome conditions make the approach unsafe.