Precision approach path indicator: Difference between revisions

Revision as of 15:54, 17 October 2004

Revision as of 16:02, 17 October 2004

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The '''Precision Approach Path Indicator (PAPI)''' is a [[light]] system positioned beside the runway that consists of two or four boxes of lights that provide a visual indication of an airplane's position on the [[glidepath]] for the associated [[runway]].

Each box of lights is equipped with an [[optics|optical]] apparatus that horizontally splits light output into two phases: red and white. Depending on the viewing (and thus the descent) angle, a pilot will see either the red or the white portion.

A normal glidepath is indicated by twoan even split in red and two white lights. If an airplane is beneath the glidepath, more red lights visible to the pilots; if an airplane is above the glidepath, more white lights are visible.

During aircraft [[descent]], this system may be activated by the [[pilot]] by keying the airplane [[microphone]] with the airplane's communication radio tuned to the [[CTAF]].