AFIK, the N model is 24V. Make sure that you are putting in a 24V
sealed beam (Not a 12V 4509).

If the voltage is correct, the only other reason that the lamp would
blow is vibration. Wiring problems, shorts, or rubbed through wire
insulation would not cause the lamp filament to blow; rather wiring
problems would cause the breaker to trip, preventing the lamp from
lighting until the short is corrected, & the breaker is reset.

Is the lamp mounted in the lower cowling on your model? If so, then a
prop balance may be in order.

MikeM
Skylane '1mm (with landing/taxi lights in the wing l. e. Thank God!)



On Fri, 12 Sep 2003 21:08:27 GMT, Chick Urick
wrote:

The landing light in my 1979 Cessna 172N keeps blowing out. I have
replaced it 3 time and rarely use it. The past bulb hasn't been
lighted more than 3 minutes, max. I preflight and it is fine, went to
land - dark, no light. Perhaps a lose connection (I'll) check again
or possible a surge in the electrical system? Any thought would be
appreciated. Thanks C.Urick (VA)