AAIB (H) UK - serious incident report June 2022
 

HEMS MD900 parked on the pad for several hours in heavy rain, random electrical problems on the subsequent flight due to water ingress. Landed uneventfully.

Link: here

The manufacturers still can't make a weatherproof helicopter it seems........

A nasty incident, especially bearing in mind where it occurred, well managed by the crew.

Having flown helicopters where water ingress has caused multiple failure indications I can imagine how much stress they would have been under!

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.

There has never been a Helicopter that did not leak water like a sieve.

I have worn a rain jacket for a few....in the cockpit in flight.

There shall never be one built that does not leak somewhere on the airframe.

Sikorsky Rotor Brakes have ruined more White Shirts than I care to remember....till finally we just surrendered and started wearing shirts with a pink left shoulder and sleeve.

Problem is that modern avionics really doesnt like it.

Some time back had a 365 return with the instrument panel looking like Blackpool illuminations.
Traced to a missing grommet on a windshield wiper arm that had allowed rather a lot of water into the master electrical box in the nose.
When we dropped the cover we got a pint of water out. It was sloshing back and forth across the cards resulting in the amazing light display..
The surprise was that only one card was damaged everything else was fine once dried out.

Be fair. Designing any vehicle that is picked up by its roof (often comprising glass panels) and put down again several dozen times a day, and that stays waterproof despite all that flexing, isn't easy. Especially when it has to be very light, work in a 100 knot wind, and last 30 years.

Had an AW109 with leak down from the overhead with the owner in the front seat and it was conveniently dripping on his leg. As he mentioned it I told him it was also dripping into the FADEC controls which was my main concern! I

Incidentally a cockpit leak in a Transport Category aircraft is a fairly serious defect as pretty sure the Type Design criteria says it shouldn't.

when I was at Mesa I asked them about waterproofing as my new 600 used to drip into the radios and Gps they said it was ok when it left the factory it didn’t leak there
but it doesn’t rain there either

My R44‘s didn’t leak from rain, neither when parked outside, nor inflight.

None of the EC135s that I flew leaked. Don't recall the various Gazelles and Lynxes leaking either.

Airbus DE have a big rig that they test them all in before delivery. Pretty impressive and concur that 135's and 145's don't leak (mostly). Did find one 135 where they were a bit shy with the Pro-Seal.

All true, I'm sure, but I was talking serious helicopters!

Leonardo UK products (and assumed Italian also) have similar rigs to peform leak tests prior to delivery, however i will rely on the relevant drivers and maintainers to confirm if they stay watertight once in service...

(not water related, but…)
If a Lynx wasn’t leaking, it had run out of oil :ok:

Very true. :E

It was not reallt an oil leak. It was the continuous corrosion reduction system at work. Also fitted to the Sea King.
N

Chinooks leaked enough hydraulic fluid and Oil that it was thought an EPA Impact Statement might be required for each landing site.

Flew an almost brand new 225 that leaked like a sieve. Mostly down the co-pilots leg (mine) from just above the knee.