KC135 Aircraft LED Lighting Success Story

PROBLEM: Replace aging incandescent navigation lights (wingtip and tail), boom spot light and pilot director lights with modern LED versions on the KC135 tanker aircraft. Multiple brightness level adjustments and flash modes must be preserved, and covert modes must be added. FAR illumination pattern requirements must be met, no changes can be made to the aircraft wiring and conversion must take no longer than 20 man-hours to complete.

SOLUTION: Design new fixtures for wingtip, boom spotlight and tail light. Design new lamp assemblies for the pilot director lights. Design and replace variable controls with switched controls that signal over the existing power wiring. No wiring is added and the modification consists of drop-in replacement of controls and fixtures.

RESULTS: Ground and flight testing is complete. System has been in operation on test aircraft for over 18 months without any failure of any kind. In addition, no maintenance has been needed whatsoever, in contrast to the incandescent lighting which requires constant bulb replacement.


This is the original wingtip fixture assembly. The new assembly is designed to bolt onto the wingtip in place of this fixture.

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This is the replacement wingtip fixture assembly. An analysis of the airflow over the wingtip shows that the deeper housing does not add any drag, as leading edge of the wing creates a wind shadow.

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Here, the PDI light conversion is almost complete. The lights are quite bright. One of our few change requests was to actually make the lights dimmer.

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This is a view of the PDI lights taken at midday in August on the tarmac in Phoenix. Sunlight doesn’t get much brighter than this, and the PDI lights are still clearly visible.