Slight problem with aircraft landing lights. Only 25 hour rated life.
Sealed Beam Lamp, Trade Lamp No. 4509, Watts 100, 13 Volts, PAR36 Lamp Shape, Aircraft, Screw Terminal Base, Lamp Type Halogen, Rated Average Life Hours 25, Candle Power 110, 000, Diameter 4 1/2 In, Max Overall Length 2 3/4 In
If you want to use a PAR36 for a backup light let me know. Bought a ton and tested them for just that purpose a few years back. I'll go outside and pop the bulbs out if you're interested. Found three that work well.