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5-34 Rod Machado’s Instrument Pilot’s Handbook
stop at the runway threshold. The “F” in the
ALSF designation stands for sequenced flashing The ALSF
lights (brilliant white bursts of light appearing Lighting
as a ball of light moving toward the runway). System
Where possible, sequenced flashing lights are
built into the approach lighting system and stop
at the approach light’s decision bar, which is
located 1,000 feet from the runway threshold
(Figure 59). Because they appear to run quickly
as they flash in sequence, the sequenced flashing
lights are sometimes called “the rabbit.” So
don’t call the animal protection squad if you
hear a pilot ask the controller to “Kill the rab-
bit”. They’re not cooking up a hasenpfeffer din-
ner date. It’s simply a request to turn off the
sequenced flasher, which some pilots find so
intense it makes them tense (and makes it diffi-
cult for them to make the instrument to visual
transition for landing, too). As a general rule, any
ALS system that’s 2,400 to 3,000 feet in length is
usually associated with a precision instrument
runway as shown in Figure 60 B and D.
Nonprecision instrument runway ALSs are
typically (but not always) 1,400 feet in length as
shown in Figure 60, A, C and E. Here are exam-
ples of the five additional categories of approach
light systems:
1. Figure 60A shows a typical MALS or medi-
um intensity approach light system, consisting
of seven white light bars separated by 200 feet
in length for a total length of 1,400 feet. Fig. 59

Precision and Nonprecision Instrument Runway Approach Lighting

Fig. 60