The manufacturers still can't make a weatherproof helicopter it seems........
We had water comming out of the overhead circuit breaker panel on 139. After investigation it was found that the sealing at the manufacturers joint between the cockpit and the rear fuselage had broken down to the point that you could actually pour water on to the joint and watch it disapppear into the aircraft. Easily fixed by a half inch wide band of PRC from the top of one crew door over the top of the fuselage to the top of the other crew door.
During water testing we found and fixed a further 5 leaks!!!!!
Seems to be a problem when parked and not in flight. In bad weather if not due to fly we tow back to the hangar.