Rain water accumulated in a B727 E&E compartment and caused a #2 generator control over/under voltage trip. The crew disconnected the generator. After landing; the voltage regulator was removed; dried out and reinstalled with no further problems.

Narrative

In the spirit of this program I would like to provide information pertaining to a problem with excessive moisture in the E&E compartment of a B727 cargo aircraft. The aircraft was loaded in heavy rain conditions and water drained down into the E&E compartment water soaking the components. After startup and blockout the #2 Generator showed erratic operation with a fault of over and under volts. The CSD was disconnected and crew placed it on the MEL list. Upon arrival at station it was discovered the E&E compartment was still water soaked along with the #2 voltage regulator. No further tests were done at this time to allow time for the aircraft to dry out. A voltage regulator was ordered as a precaution. The voltage regulator for #2 system was brought into the office to dry out. Turnover was giving on the condition of the moisture in the E&E and a regulator was ordered as a precaution if the original regulator did not check out. After approx 10 hrs of drying out time tests and checkout was preformed by this AMT. The connectors on the regulator and shelf were checked and cleaned with contact cleaner. The original regulator was installed and ops check performed per the procedures. No problems were noted and the aircraft was restored to normal configuration and released. Additional moisture cleanup was preformed as it was still wet. The voltage regulator on order was not received until after the flight departed. This had no bearing on the signoff as this AMT was satisfied with the checkout and safety of the system. This AMT has been dealing with this problem on this airframe for thirty years and has seen many erratic problems caused by moisture in the E&E. Once given time to dry out everything works like normal. There have been problems discovered with burnt pins and component damage which need replacing. This aircraft flew five legs without any problems before the regulator was changed as a precaution.Callback conversation with reporter revealed the following information: The reporter stated that generator regulators; autopilot and navigation equipment are in the same vicinity as the malfunctioning voltage regulator. Generally when water gets into the E&E; erratic component behavior is seen. But after the components dry out normal operation returns. Reporter stated the air carrier has installed drip shields over the equipment to protect it and has sealed the floors above in an attempt to prevent water seepage into the E&E. Yet water does still accumulate when the cargo door is left open in heavy rains. When water is discovered the affected equipment is removed to dry out.