b. Signal strength or quality of the received signal falls below acceptable values. 

## FLAG ALARM- 

(See FLAG.) 

FLAMEOUT- An emergency condition caused by a loss of engine power. 

FLAMEOUT PATTERN- An approach normally conducted by a single-engine military aircraft experiencing loss or anticipating loss of engine power or control. The standard overhead approach starts at a relatively high altitude over a runway (“high key”) followed by a continuous 180 degree turn to a high, wide position (“low key”) followed by a continuous 180 degree turn final. The standard straight-in pattern starts at a point that results in a straight-in approach with a high rate of descent to the runway. Flameout approaches terminate in the type approach requested by the pilot (normally fullstop). 

FLIGHT CHECK- A call sign prefix used by FAA aircraft engaged in flight inspection/certification of navigational aids and flight procedures. The word “recorded” may be added as a suffix; e.g., “Flight Check 320 recorded” to indicate that an automated flight inspection is in progress in terminal areas. 

(See FLIGHT INSPECTION.) 

(Refer to AIM.) 

## FLIGHT FOLLOWING- 

(See TRAFFIC ADVISORIES.) 

FLIGHT INFORMATION REGION- An airspace of defined dimensions within which Flight Information Service and Alerting Service are provided. 

a. Flight Information Service. A service provided for the purpose of giving advice and information useful for the safe and efficient conduct of flights. 

b. Alerting Service. A service provided to notify appropriate organizations regarding aircraft in need of search and rescue aid and to assist such organizations as required. 

FLIGHT INFORMATION SERVICE- A service provided for the purpose of giving advice and information useful for the safe and efficient conduct of flights. 

FLIGHT INFORMATION SERVICE- BROADCAST (FIS-B)- A ground broadcast service provided through the ADS-B Broadcast Services 

network over the UAT data link that operates on 978 MHz. The FIS-B system provides pilots and flight crews of properly equipped aircraft with a cockpit display of certain aviation weather and aeronautical information. 

FLIGHT INSPECTION- Inflight investigation and evaluation of a navigational aid to determine whether it meets established tolerances. 

(See FLIGHT CHECK.) 

(See NAVIGATIONAL AID.) 

FLIGHT LEVEL- A level of constant atmospheric pressure related to a reference datum of 29.92 inches of mercury. Each is stated in three digits that represent hundreds of feet. For example, flight level (FL) 250 represents a barometric altimeter indication of 25,000 feet; FL 255, an indication of 25,500 feet. 

(See ICAO term FLIGHT LEVEL.) 

FLIGHT LEVEL [ICAO]- A surface of constant atmospheric pressure which is related to a specific pressure datum, 1013.2 hPa (1013.2 mb), and is separated from other such surfaces by specific pressure intervals. 

Note 1: A pressure type altimeter calibrated in accordance with the standard atmosphere: 

a. When set to a QNH altimeter setting, will indicate altitude; 

b. When set to a QFE altimeter setting, will indicate height above the QFE reference datum; and 

c. When set to a pressure of 1013.2 hPa (1013.2 mb), may be used to indicate flight levels. 

Note 2: The terms ‘height' and ‘altitude,' used in Note 1 above, indicate altimetric rather than geometric heights and altitudes. 

FLIGHT LINE- A term used to describe the precise movement of a civil photogrammetric aircraft along a predetermined course(s) at a predetermined altitude during the actual photographic run. 

FLIGHT MANAGEMENT SYSTEMS- A comput- er system that uses a large data base to allow routes to be preprogrammed and fed into the system by means of a data loader. The system is constantly updated with respect to position accuracy by reference to conventional navigation aids. The sophisticated program and its associated data base ensures that the most appropriate aids are automati- cally selected during the information update cycle. 

