Plain English Meaning

A specific pattern of bright lights laid out in front of the runway to help a pilot find and line up with the runway when the weather is very bad. It includes a line of lights running away from the runway, a chasing flash that points the way in, and red and green markers showing the threshold and the final stretch.

Full Definition

A high-intensity approach lighting system installed at the approach end of a runway served by a Category II or Category III instrument approach. It consists of steady-burning white lights extending 2,400 feet from the runway threshold along the extended runway centerline, a sequenced flashing (a '') that pulses toward the runway, a green threshold light , a 1,000-foot crossbar, and red side row barrettes in the inner 1,000 feet to provide guidance in .