The FAA has issued an information for operators bulletin (InFO) regarding the use of light-emitting diode (LED) landing lights in an icing environment. It warns that aircraft equipped with LED landing lights might experience icing on the lights or lenses more frequently than those with incandescent bulbs, resulting in reduced light output and potential diminished visibility for pilots.
Operational experience has shown that retractable LED landing lights such as those used on Airbus A319/320/321 models, as well as Boeing MD-88/90s and 717s, can become ineffective during the landing phase due to icing, which can reduce their output by one-third.
According to the FAA, tests demonstrate that it takes approximately 20 minutes for the LED lights to warm to the point that they can begin melting any accumulated ice. The LEDs tested showed a slow initial temperature increase, followed by a relatively linear rise to exceed the freezing point at the center of the lens.
As a result, the agency recommends that operators of aircraft so-equipped should consider modifying their operations during icing conditions to mitigate any effects of the reduced LED landing light output.