What is qfe in aviation

Understanding QFE

QFE is a critical altimeter setting in aviation that represents the atmospheric pressure at the elevation of an airport or airfield. When a pilot sets their altimeter to QFE, the instrument displays height above ground level (AGL) rather than altitude above mean sea level (AMSL). This is particularly useful during takeoff, landing, and other low-level operations where knowing exact height above the runway is essential for safety.

How QFE Works

The altimeter is a barometric instrument that converts atmospheric pressure readings into altitude information. When set to QFE, the altimeter is calibrated to show zero feet when the aircraft is on the ground at that specific airfield. As the aircraft climbs, the decreasing atmospheric pressure causes the altimeter to indicate height above that reference point. This direct reading of height above ground makes it easier for pilots to maintain safe clearances during critical flight phases.

QFE vs QNH

QNH is the standard atmospheric pressure adjusted to sea level, while QFE is adjusted to the airfield's actual elevation. QNH provides a consistent reference point globally, whereas QFE gives local, immediate altitude information. Pilots typically use QFE during approach and landing phases, then switch to QNH once established at cruise altitude. The transition occurs at a designated transition altitude, which varies by country and region.

Regional Variations

Different countries use QFE with varying frequency. European aviation heavily emphasizes QFE settings during terminal operations, while some regions use it less frequently. Pilots must always confirm which setting is required for their destination airfield and obtain the correct QFE value from air traffic control before descent. Failure to use the correct altimeter setting is a serious safety concern that can lead to altitude errors and near-ground-level incidents.

Obtaining QFE Information

Pilots receive QFE information through multiple channels including ATIS (Automatic Terminal Information Service), direct radio contact with air traffic control, and aviation weather reporting systems. The QFE setting must be obtained shortly before landing because atmospheric pressure changes continuously. Charts and flight planning documents typically provide QFE information, and modern aircraft may receive it through data-linked systems for automatic altimeter adjustment.