The PAPI system uses either two-light channel or three-light channel units, which offer the pilot information to carry out the approach procedure with the utmost accuracy and safety. The L-880 PAPI system consists of four light units located at the side of the runway adjacent to the origin of the glide path. The L-881 is very similar to the L-880 except it only uses two lights.
- FAA: L-880 & L-881 AC 150/5345-28 (Current Edition) ETL Certified.
- ICAO: Annex 14, Vol. 1, para. 184.108.40.206 to 220.127.116.11