aviation Aviation includes the activities surrounding mechanical flight and the aircraft industry. ''Aircraft'' includes fixed-wing and rotary-wing types, morphable wings, wing-less lifting bodies, as well as lighter-than-air craft such as hot air ...

, a traffic pattern indicator is a L-shaped device which show the

airfield traffic pattern An airfield traffic pattern is a standard path followed by aircraft when taking off or landing while maintaining visual contact with the airfield. At an airport, the pattern (or circuit) is a standard path for coordinating air traffic. It differ ...

to the in-flight aircraft over an

aerodrome An aerodrome (Commonwealth English) or airdrome (American English) is a location from which aircraft flight operations take place, regardless of whether they involve air cargo, passengers, or neither, and regardless of whether it is for publ ...

. The short arm of the "L" represents the

base leg An airfield traffic pattern is a standard path followed by aircraft when takeoff, taking off or landing while maintaining visual contact with the airfield. At an airport, the pattern (or circuit) is a standard path for coordinating air traffic co ...

, and the long arm the

final approach In aeronautics, the final approach (also called the final leg and final approach leg) is the last leg in an aircraft's approach to landing, when the aircraft is lined up with the runway and descending for landing.Crane, Dale: ''Dictionary of ...

References

Air traffic control {{aviation-stub