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-   -   Debris Found in Undelivered 737MAx FUEL TANKS (https://www.pprune.org/safety-crm-qa-emergency-response-planning/629864-debris-found-undelivered-737max-fuel-tanks.html)

clearedtocross 25th Feb 2020 10:34

ST Dog

Safe or FOD free?

I am sorry to disagree. A production process or maintenance procedure that does not care to remove FOD is not safe, regardless of the type of FOD. I once nearly got killed because some guy left a screwdriver in a wing of a Cessna 182. Surprise surprise when I raised the flaps after a training touchandgo and only the starboard flap retracted.

Dog Star 25th Feb 2020 16:05

All aerospace workers must have tools marked, bonuses long term tied to success of their assembly line efforts

ST Dog 25th Feb 2020 17:21

A screwdriver is quite different than some wire insulation or drilling swarf

When we did FOD walkdowns on the airfield not every little bit was of concern. Only things that could be picked up by an engine and do damage.

Not all FOD is equal in all situations.

That's why we need more detail about what was found to determine the seriousness.

Could it have caused a crash? Just an early landing? Or just short fuel filter life.

DaveReidUK 25th Feb 2020 17:33

Most definitions of FOD describe it only in terms of the sadly inevitable objects and material that are to be found on the manoeuvring area of an airport, left there by anonymous persons whom it's impossible to control.

There's no mention of debris left on an aircraft by AMEs as a consequence of manufacture or maintenance - that's neither expected nor acceptable.

That should give you a clue.

Skybrary: Foreign Object Debris (FOD)

FlexibleResponse 25th Feb 2020 18:16

History tells us that it is pretty hard to justify any aviation manufacturing process in which FOD ends up inside the finished product. Especially in fuel tanks, control runs, electrical circuits, hydraulic systems, pitot/static systems, all other aircraft systems, components and structures (did I miss anything?).

The concept of "good" FOD as opposed to the classically defined and accepted "bad" FOD is new to me, and begs the question of what is "good" FOD and how is it objectively defined?

Jackjones1 25th Feb 2020 18:49

I did a fair bit of fuel tank work on early 747’s ... modifications repairs etc & you would be surprised where swarf/removed sealant can get too & even the most vigilant person would not get it all, the smaller the tank the harder it was to remove...... I think a fuel filter change was called for within 100 hours.

Jackjones1 25th Feb 2020 19:53

Brand new aircraft coming in from Boeing’s torches in flap track boat fairings & hammers found on shelving the list was endless & before I retired toolboxes came in with named/identified person but as anyone who has worked in the aircraft industry you always purchased other tools to help do certain tasks & did you identify them .... of course not as if they needed to be replaced if worn out or broken manufacturer would not replace as damage had occurred on identifying tool!!!

Vendee 25th Feb 2020 20:29

DaveReidUK

Of course older engineers will know that FOD originally stood for Foreign Object Damage but the acronym has been redefined in recent years. On a less pedantic note, people who have never been inside an aircraft fuel tank are unlikely to understand how complex a structure it is with so many places for foreign objects to hide. Even a clean tank can sometimes become "infected" as small bits of the PRC sealant can detach over time and accumulate in the various nooks and crannies. That's not an excuse for poor engineering practice and quality control but sometimes it can be a challenging task.

Bend alot 25th Feb 2020 20:55

clearedtocross

I am surprised the starboard flap retracted - must have had loose cables!

ST Dog 25th Feb 2020 21:42


Originally Posted by FlexibleResponse (Post 10695831)
The concept of "good" FOD as opposed to the classically defined and accepted "bad" FOD is new to me, and begs the question of what is "good" FOD and how is it objectively defined?

Who, other than you, said anything about "good" FOD?

But not all FOD is equally BAD, some is much worse and far more serious.

The whole reason you have fuel filters is because the fuel may contain non fuel particles, be it bits of rust, water, or biologic matter.

My suspicion is the is something that the filters would catch (and have on the AC while in service) leading to a clogged filter but reduced pressure would signal it before it was dangerous vs something like a rag that could suddenly block the fuel pickup.

But again, we don't know because no reporting has covered what was found (material, size, etc)

ST Dog 25th Feb 2020 21:49


Originally Posted by Vendee (Post 10695918)
Of course older engineers will know that FOD originally stood for Foreign Object Damage but the acronym has been redefined in recent years.

This thread was the first time I had heard it refer to this new definition.


tdracer 25th Feb 2020 23:11

I think it changed about 10 years ago to make it more generic. Never cared much for the new definition.
We also used to talk about "DOD" - Domestic Object Damage - usually referring to down stream engine damage that resulted from liberated engine bits such as broken blades on the like.

Fris B. Fairing 26th Feb 2020 04:17

I believe the original term was Foreign Object Damage. The things that caused it were just foreign objects.

Hugo1980 4th Apr 2021 22:37

Tony Mabelis

I've heard various versions of this story from Australia to UK. But I've never been able to confirm any of them.
I'm sure large objects have been found in fuel tanks but everyone who tells the story swears they were there.😂

Big Pistons Forever 5th Apr 2021 04:58

Quality construction on a production line takes time and costs money. When you have a Boeing company culture that from the very top prioritized build speed and cost reduction over build quality, I find it amazing that anybody is surprised at the continuing steady parade of news outlining QA failures at Boeing.

Sadly I think the rot is too deep and all pervasive to fix absent a total reboot of the company. Boeing is one crash away from oblivion and clueless MBA bean counters in the C suite are still rearranging the deck chairs on the Titanic....


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