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 ...

, 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 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 ...

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, and the long arm the final approach.

References

Air traffic control {{aviation-stub