B787 has a case of the drip
 

The Canadian Press
Fri, April 7, 2023 at 1:23 p.m. CST·2 min readhttps://s.yimg.com/ny/api/res/1.2/Zv...215141e1620b6cRegulators are worried that faucet leaks in Boeing 787 jets could pose a safety hazard by water seeping into the planes' electronics during flights.
https://ca.news.yahoo.com/faa-says-l...155226495.html

In my experience, this is something to bear in mind with any galley or toilet leak....what is below the area of the leak. Wasn't there a video 4-5 years ago of water leaking into an A346 (?) avionic bay?
Personally on the 787, I'd be more concerned about fluid leaks from the liquid cooling system around some big power users in centre avionic bay!

The article seemed remarkably objective. Symptoms were detected (wet carpets), analysis was conducted and the root cause detected (defective o-rings in the faucets), a recurring inspection is being proposed by the FAA to check for secondary damage (ingress around electronic components), and the faucet OEM is fixing the problem. Not really sure how more objective that could be?

Seem to recall a Vanguard suffering a (fatal?) accident after bulkhead corrosion from leaky toilets/erratic male aim.

Aarsele, Belgium, 1971. All 63 on board died.

But, as you rightly say, not really comparable in either cause or effect to the 787 issue.

I remember that vividly! I was flying a Britannia,when we were a short distance in front of it over Belgium, and a few thousand feet above it when all of a sudden the Vanguard started to descend rapidly. We did not find out what had happened until sometime after landing at Brize Norton.

Is this a "defective O-ring" issue, or could it be the parts where the O-ring creates a seal in between are connected to different "fixed" parts, which in turn can move (as designed) relative to each other ?

Or so to say, is this a design issue ? O-rings normally don't structurally fail, unless something is overseen in the design (IE moving parts, over pressure, temperature range or housing expansion effects, etc).

Not a word about this aspect in the FAA instruction. Worrying.

I can't recall ever having seen an O-ring used as a seal between moving parts. Maybe I've led a sheltered life. :O

No problem, let me open your eyes.

It's not "moving" in the sense it is supposed to move (freely).

But, when one side of the connection is (for example) connected to the sink and the other side of the connection is connected to the toilet side wall, it looks "fixed" at first sight. However, the sink and the side wall are probably not connected rigidly, more just like normal kitchen cabinets, it's connected, but apply some force and the connection moves. Even, when it's only a little bit.

So, when the whole airplane becomes "dynamic", rattling, shaking, bending, etc (even when just a little bit), that O-ring connecting starts moving, just a little bit. Though that is enough to let an O-ring fail, over time.

I hope, it's clear, what is meant with "moving".

That's rather sexist madam.
You're just lucky that you get to sit down.

Not really a story, as any sort of internal leak in an airliner can be a problem. All the airliners I have worked on in recent years have measures to mitigate leaks from toilets/galleys or elsewhere.

These normally consist of extra barrier protection in the case of cabin floor areas under and around galley and toilet areas [liquid proof barrier coatings/coverings]

Specific overflow drains around galley areas that drain either to outside or into the grey water system.

Drip trays and drains in avionic bays above electronic equipment that drain away any leaks or excessive condensation

Not so lucky after that male has just sprayed over the seat

Yeah, that's what everybody thinks and says.

Reality is, I do more often enter (unisex) toilets with wet toilet seats, being used just before by a female. Probably due to some kind of attempt to "hang" above the toilet out of hygiene concerns (which solution, women often seem to raise as a resolution for "their" problem), and happily spraying around some more watery substance, effectively all over the place.

AND, if the male is the offender, it's Boeing making life difficult: On the B737NG versions, the toilet seat does not stay upright in the front toilet due to a wrong toilet geometry and/or a missing/failing magnet. The more backwards toilets may suffer the same issue.

Gulf Air grounded their 767 fleet due to severe corrosion caused by leaks from the toilets. Took some time to get them in the air again. The problem for the ME carriers is not just waste spillage on the floors, but many muslims perform the ablution ritual in the aircraft toilets when they travel. That means a lot of water on the floors.

Were some of the VC10s that came to the RAF from a certain location not similarly affected?

On 7 January 2008, a QANTAS Boeing Company 747-438 aircraft, registered VH-OJM, was being operated on a scheduled international regular public transport service between London, England and Bangkok, Thailand. The aircraft had 346 passengers and 19 crew on board, including four flight crew. On descent to Bangkok International Airport, the customer service manager notified the flight crew that a substantial water leak had occurred in the forward galley.

The cockpit indications progressively showed a number of electrical power-related malfunctions, and many of the aircraft's communication, navigation, monitoring and flight guidance systems were affected. A number of flight and navigation display and other instruments were available in degraded mode and the standby instruments and instrument landing system were also available. The aircraft's engines and hydraulic and pneumatic systems were largely unaffected and an approach was made to Bangkok in day visual meteorological conditions.

The investigation found the galley leak was from an overflowing drain after a drain line had been blocked with ice that formed due to an inoperable drain line heater. The water flowed forward and through a decompression panel into the aircraft's main equipment centre before leaking onto three of the aircraft's four generator control units, causing them to malfunction and shut down.

The investigation identified a number of safety issues in regard to the protection of aircraft systems from liquids, and other factors including the provision of information to flight crews. In response, the aircraft manufacturer and operator implemented a number of safety actions intended to prevent a recurrence. In addition, the United States Federal Aviation Administration issued a notice of proposed rulemaking to adopt a new airworthiness directive for certain 747-400 and 747-400D series aircraft to install improved water protection.

Full report https://www.atsb.gov.au/sites/defaul.../ao2008003.pdf

I read the report on this here.

While not necessarily relevant to the 787, as it was mentioned it may be worth noting that page 20 of the report notes a blocked drain, and page 30 states "... there was no positive evidence in the wreckage of either area of corrosion having been associated with toilet liquid spillage".

Make of that what you will, but at this remove I think the bigger picture around inspections and managing any possible spillage etc more important than than a focus on wee?

FP.

Some 727 freighters had issues with water entering while the cargo door was open if it was raining or snowing. Extra sheeting was installed in the belly to route the water away from critical stuff.

I remember a BAC 1-11 that had steering problems after landing, had to be towed off the runway. Inspections were performed, no fault found, off you go, on return the same thing happened again, more inspections, functions, etc, no fault found. The third time it happened, some bright fitter decided to have a look around before they towed it off the runway. He found a water leak from the forward toilet had dripped on to the nose wheel steering control cables and frozen solid. The reason it hadn't been found before is that by the time the aircraft had been dragged off the runway and inspections began it had all melted away.

There was the time a 727 mast heater failed and ice built up, when the ice came off it went into No 3 engine causing spool lock which made the engine separate from the airframe.