Airborne Measurements of Transient Electric Fields and Induced Transients in Aircraft Due to Close Lightning
Final rept. Jul-Aug 1976
AIR FORCE FLIGHT DYNAMICS LAB WRIGHT-PATTERSON AFB OH
Pagination or Media Count:
The electromagnetic environment near lightning and thunderstorms and the induced effects of this environment on aircraft wiring was measured as part of Project Thunderstorm TRIP-76. Instrumentation consisted of an externally mounted transient electric field sensor, induced transient sensors within the aircraft, a discrete spectrum analyzer, and a computer-based waveform digitizing system for high-resolution, high-frequency measurements. The electric field environment near thunderstorms was found to be very active with transients even when no lightning was evident. This environment was also responsible for inducing transients on wiring within the aircraft on an almost continuous basis in the vicinity of storms. The spectral content of pulses observed externally and internally on the aircraft varied widely with time. Comparison between the induced transients due to an accidental direct lightning strike to the aircraft and those due to a nearby strike showed the magnitudes of the effects due to the nearby strike to be nearly half those of the direct strike. The induced transients observed in the Learjet were similar in duration, magnitude, and frequency content to those observed during ground simulated lightning tests on other aircraft.
- Electricity and Magnetism