B787 has a case of the drip

[BlankBox]

The Canadian Press
Fri, April 7, 2023 at 1:23 p.m. CST·2 min readhttps://s.yimg.com/ny/api/res/1.2/ZvhRukRbF6EHfKWaa8VAAg--/YXBwaWQ9aGlnaGxhbmRlcjt3PTk2MDtoPTY0MDtjZj13ZWJw/https://media.zenfs.com/en/cp.org/c3114a4bddcecc0820215141e1620b6cRegulators 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-leaky-faucets-safety-155226495.html

[Tom Sawyer]

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!

[Two's in]

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?

[DType]

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

[DaveReidUK]

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.

[brakedwell]

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

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.

[WideScreen]

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?
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.

[DaveReidUK]

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 ?

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

[WideScreen]

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".

[WingNut60]

Seem to recall a Vanguard suffering a (fatal?) accident after bulkhead corrosion from leaky toilets/erratic male aim.
That's rather sexist madam.
You're just lucky that you get to sit down.

[MAC 40612]

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

[Sallyann1234]

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

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

[WideScreen]

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.

[ManaAdaSystem]

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.

[Flying_Scotsman]

Seem to recall a Vanguard suffering a (fatal?) accident after bulkhead corrosion from leaky toilets/erratic male aim.
Were some of the VC10s that came to the RAF from a certain location not similarly affected?

[megan]

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/default/files/media/3440510/ao2008003.pdf

[First_Principal]

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 read the report on this here (https://www.gov.uk/aaib-reports/15-1972-g-apec-2-october-1971).

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.

[MarkerInbound]

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.

[HOVIS]

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.

[megan]

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.

[slacktide]

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

Every airplane I've ever designed a part for has many many thousands of NAS1611 O-rings used in various places as sliding/rotating shaft seals in the hydraulic system.

[tdracer]

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.
I remember it a bit differently - I thought it was 'blue ice' from a leaking lav service panel.
But I suppose it really doesn't matter much in the end (aside from corrective action at the time).
Mildly humorous story about that incident - apparently there was an engineer type sitting near the #3 engine - he heard a bang and looked out the window and saw that the engine was gone! So he called a flight attendant over and said 'WE JUST LOST AN ENGINE' - the flight attendant started with the standard response that it's not uncommon to shut down an engine - the aircraft can still fly fine when the engineer stopped her and said 'NO! The engine is GONE' and pointed to the window. The FA looked out the window, gasped, and headed for the flight deck.
Meanwhile the pilots had gotten some warnings about the engine - pulled the fire handle and figured they were done. The FA came in an told them the engine was GONE - so the flight engineer went back and looked. Shocked, he returned to the flight deck and one of the pilots came back and looked...
Back in the flight deck, they decided the aircraft was still flying just fine, so they continued on to their destination...

[DaveReidUK]

Every airplane I've ever designed a part for has many many thousands of NAS1611 O-rings used in various places as sliding/rotating shaft seals in the hydraulic system.

Then I stand corrected.

I've come across plenty of hydraulic actuators in my career, just none with seals that were remotely O-shaped, but clearly I was wrong to rule out their existence.

[megan]

I remember it a bit differently - I thought it was 'blue ice' from a leaking lav service paneBetter memory than me td :ok: You're correct of course, Northwest Flight 5 report,THE FORWARD LAVATORY EXTERNAL SEAL WAS MISSING THE SAFETY BUTTON AND THE INTERNAL SEAL WAS IMPROPERLY INSTALLED ALLOWING FOR LEAKAGE WHEN THE AIRPLANE WAS PRESSURIZED. THE FUSELAGE EXTERNAL SKIN AFT OF THE FORWARD LAVATORY SERVICE PANEL WAS STAINED WITH BLUE FLUID

[stilton]

I remember it a bit differently - I thought it was 'blue ice' from a leaking lav service panel.
But I suppose it really doesn't matter much in the end (aside from corrective action at the time).
Mildly humorous story about that incident - apparently there was an engineer type sitting near the #3 engine - he heard a bang and looked out the window and saw that the engine was gone! So he called a flight attendant over and said 'WE JUST LOST AN ENGINE' - the flight attendant started with the standard response that it's not uncommon to shut down an engine - the aircraft can still fly fine when the engineer stopped her and said 'NO! The engine is GONE' and pointed to the window. The FA looked out the window, gasped, and headed for the flight deck.
Meanwhile the pilots had gotten some warnings about the engine - pulled the fire handle and figured they were done. The FA came in an told them the engine was GONE - so the flight engineer went back and looked. Shocked, he returned to the flight deck and one of the pilots came back and looked...
Back in the flight deck, they decided the aircraft was still flying just fine, so they continued on to their destination...


With no engine driven hydraulic pump on the #3 engine it was the least worst one to drop

[WideScreen]

Then I stand corrected.

I've come across plenty of hydraulic actuators in my career, just none with seals that were remotely O-shaped, but clearly I was wrong to rule out their existence.
As long as the O-shaped seals aren't loaded beyond their specifications, no problem, think about aspects like lubrication, cleanliness, deformation, load forces, sheering, etc.

The issue arises, when O-rings are being used in a presumed "static" situation and contamination of the sealing areas happens, then a "vibrating" static situation, will result in the contamination working itself into the sealing and leaking will start (including damaging the seal material itself). This is typically something to be expected, when the 2 sides of a seal are attached to different "fixed" mountings: The seal starts moving, the contamination works itself into the seal and the leaking starts.

[MissChief]

I remember it a bit differently - I thought it was 'blue ice' from a leaking lav service panel.
But I suppose it really doesn't matter much in the end (aside from corrective action at the time).
Mildly humorous story about that incident - apparently there was an engineer type sitting near the #3 engine - he heard a bang and looked out the window and saw that the engine was gone! So he called a flight attendant over and said 'WE JUST LOST AN ENGINE' - the flight attendant started with the standard response that it's not uncommon to shut down an engine - the aircraft can still fly fine when the engineer stopped her and said 'NO! The engine is GONE' and pointed to the window. The FA looked out the window, gasped, and headed for the flight deck.
Meanwhile the pilots had gotten some warnings about the engine - pulled the fire handle and figured they were done. The FA came in an told them the engine was GONE - so the flight engineer went back and looked. Shocked, he returned to the flight deck and one of the pilots came back and looked...
Back in the flight deck, they decided the aircraft was still flying just fine, so they continued on to their destination...

727 does fine on 2 engines in the cruise. Heard one go paxing from Benghazi to Tripoli, positioning with the local lot, and all went fine. Guess they were used to it. Early 2001, I recall.

[Checkboard]

OF course there's this video of a waterfall on a BA A380:
https://www.dailymail.co.uk/news/article-10915703/Water-POURS-cabin-British-Airways-flight-30-000-feet-Airbus-A380-Heathrow.html

`BA said: 'There was no safety issue at any point, this was from the clean drinking water supply.

'The flight continued safely to Washington and landed as normal.

[condor17]

TD , isn't that why Boeing call it ''Engine , Fire , Severe damege , or Separation '' C/list/QRH ..
Does memory serve that an Hawaiian/Aloa ? 737-200 lost an engine when the backmost of 3 bolts holding it sheared , and said eng. departed over the top of the wing ?

rgds condor

[DaveReidUK]

Does memory serve that an Hawaiian/Aloa ? 737-200 lost an engine when the backmost of 3 bolts holding it sheared , and said eng. departed over the top of the wing ?

If that happened, they kept it very quiet ...

[WideScreen]

TD , isn't that why Boeing call it ''Engine , Fire , Severe damege , or Separation '' C/list/QRH ..
Does memory serve that an Hawaiian/Aloa ? 737-200 lost an engine when the backmost of 3 bolts holding it sheared , and said eng. departed over the top of the wing ?

rgds condor
You intend to refer to the B737 that became a convertible ? I didn't read about that aircraft also physically losing an engine.

[HOVIS]

You intend to refer to the B737 that became a convertible ? I didn't read about that aircraft also physically losing an engine.
Perhaps getting mixed up with EL AL 1862?
https://en.wikipedia.org/wiki/El_Al_Flight_1862

[WideScreen]

Perhaps getting mixed up with EL AL 1862?
https://en.wikipedia.org/wiki/El_Al_Flight_1862
Yeah, maybe, though the difference between those events is that big, that I could not imagine it to be a mix-up. The EL AL did lose 2 engines, where the first one (#3) knocked off the other one (#4). Not sure, whether the engines went backwards over the wing, I don't think so.

The AA191 DC-10 accident comes closer, regarding loosing an engine "over the wing".

[tdracer]

You intend to refer to the B737 that became a convertible ? I didn't read about that aircraft also physically losing an engine.

The engine didn't physically depart the aircraft. However apparently one engine did shutdown - as I understand it, the 737-200 had a cable actuated fuel shutoff. When the top of the fuselage ripped off, the floor (where the cable run was located) distorted sufficiently that it tripped the fuel shutoff cable.
I certainly don't recall any 737 events where the engine departed the airframe. There of course where the two 747 events where the #3 engine fuse pin failed and as the engine departed it struck the #4 engine causing it to also depart - both freighters (not a complete coincidence). Not as many people know about the first event since only the crew was lost (plus, the engines were lost over the ocean and never recovered - we literally couldn't figure out how they could have lost two engines 'at once'). The El Al event unfortunately hit the apartment building resulting in high death toll, but the engines were found and recovered which revealed what had happened so the root cause could be corrected.

[DaveReidUK]

I certainly don't recall any 737 events where the engine departed the airframe

A bit more digging comes up with a surprising number:

DAL Jan 1986
PHL Dec 1987
ORD Jan 1989
DFW Jan 1992
CPT Nov 2007

[First_Principal]

A bit more digging comes up with a surprising number:

DAL Jan 1986
PHL Dec 1987
ORD Jan 1989
DFW Jan 1992
CPT Nov 2007

I was interested to follow up these incidents, for anyone wanting more detail some information is available here (https://aviation-safety.net/database/record.php?id=20071107-0). here. (https://aviation-safety.net/wikibase/147099) here. (https://aviation-safety.net/database/record.php?id=19890120-2) here. (https://aviation-safety.net/database/record.php?id=19871205-1) and here (https://aviation-safety.net/wikibase/269209).

Not rated on the 73, and have no particular experience of them, however it appears that all the incidents involved the right or No.2 engine, and generally the initiating issue was with the 'aft cone bolt'. While it seems the root cause was mostly to do with poor maintenance (around installation of said bolt) I wonder why it would seem to only affect the right engine?

FP.

[HOVIS]

Is the No. 2 engine always started first? I remember doing torque loading checks on the aft cone bolt. Considering what it has to do, it's amazing gly small.

[Mechta]

This brings memories of seeing the outcome of what was believed to be a cleaner's mop catching a pipe on a QANTAS A380.
QF94 was traveling from Los Angeles to Melbourne when a water pipe became detached, flooding the upper deck and causing waterfalls onto those on the lower deck. It struck a chord with me as I was doing galley certification at the time and had raised a concern about an oversize waste water hose which would not seal. After emailing the photos of the A380 flood to our quality department, they told me I was being alarmist. :)
The Aviation Herald - A380 Cabin flood, QF94 2 July 2014 (https://avherald.com/h?article=476c3bbc&opt=0)

[First_Principal]

Is the No. 2 engine always started first?...

Yes, from what I read that's correct, although I must reiterate my lack of actual experience here.

Another common factor in the five incidents noted was that the failure occurred at the takeoff/climb phase of flight. I have no concept of how the engine mounting is designed but can imagine that's generally when the most load is likely to be applied to the fixings, so hardly surprising.

I guess the takehome from this is that if you're a 73 driver in the climb and your machine starts yawing to the right (and maybe the throttles retard), have a squiz out the RHS window to see if you need to issue a hard hat warning for those on the ground :eek: And if you're a mech, take great care to install said cone bolt per the approved methodology.

FP.