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Do component lifetime limits apply only since installation?

On the Socata owners group, a pilot in Turkey got a landing gear pump, overhauled, from a company in Arizona, with an overhaul date of January 1997.

How could this component possibly be airworthy?

There will be various seals in there, and nearly all seal materials have a life shorter than 20 years. Especially when inactive.

One of the people there posted that time limits apply only since installation. That may be true – not sure whether it is because I know for a fact that e.g. rubber hoses have shelf life limits – in a narrow legal sense if you are completely blind to getting a basically defective component to start with, and not installing it in your own plane

I have had the same experience, in the form of a €800 (+VAT&labour) starter motor from Socata themselves, 10-15 years old, which seized up and burnt out 2 weeks later. The first prize however goes to a 1968 P-clip, bought from a FAA145+EASA145 premium grade parts disti in the UK a few years ago, which I still have somewhere

Administrator
Shoreham EGKA, United Kingdom

To answer the title question: NO

FAA A&P/IA
LFPN

Can you post some detail, Michael?

Administrator
Shoreham EGKA, United Kingdom

If it’s FAA parts that we’re talking about then it’s the date on the 8130 that counts.

Example : Last week I bought a “newly overhauled” prop from an FAA Repair Station. They typically overhaul theirinventory props when they have time, put them on the shelf, then issue and date the 8130 at the time of the sale.

FAA A&P/IA
LFPN

It all depends on what the manufacturer describes as the FAA approved life limit. Is it calendar days, months, years? Is it cycles or hours? This is of course all N-reg stuff.

You have a landing gear pump with a life limit in hours used. The supplier sold you a twenty year old pump that is still airworthy. It has 0 hours used on it. As far as the regulations go, that pump is good to go. Now I can debate the installed A&P can then deem that pump unairworthy and refuse to install it. It has 20 year old gaskets and seals in it, of course it’s life limit wont last.

Part 43.13 – Disposition of Life Limited Parts

Last Edited by NeumannJ at 12 Nov 16:17

Ultimately any QA system is only as good as the people who operate it, and “the people” is the weakest link in any QA system I have ever come across.

If you sell a dog turd

with a QA certificate which says it is a Mars Bar

most normal people will think this is simply wrong. But that is the wrong way to look at it. The correct procedure is to suspect that the vendor’s QA procedure may have failed, and request a copy of the seller’s most recent QA audit. If he refuses to give it to you, etc, the correct procedure is to file a complaint with the certification authority.

However, the dog turd which you got is still, by definition, a Mars Bar. There is no procedure for a disagreement on it.

If you think I am kidding, welcome to the world of ISO9000, or take a look at this. It was purchased in 2008 and was 40 years old then.

I would like to think I am at least partially normal so obviously I think this is a scam, facilitated by a QA system under which if a part’s certificate says “serviceable” then it is serviceable even if it obviously isn’t. But this is really how a QA system is supposed to work. Once you start to question the paperwork, the whole edifice crumbles. I once had a heated conversation with a vendor’s QA manager (after they sold me a load of crap) who claimed that since my company was not ISO9000 I was not even authorised to buy his product, let alone question the quality! So there is a load of hangers-on who get paid very good money (and in most companies have great power) to run these systems. Just about all of aviation runs on this. For example most of the warranty replacement avionics pool is ancient crap (IME easily 20 years old) which comes with a fresh 8130-3 or EASA-1.

Administrator
Shoreham EGKA, United Kingdom

Well I sure hope you didn’t eat that mars bar then.

This is pretty relevant:



I believe that the time limit begins with the date on the unit, not date of installation – the background: A number of Cirrus pilots received ’chute repacks where the rocket motor was anything up to a year old and that meant the replacement interval was shortened by that period…..
EDL*, Germany

The problem is that a lot of the time there is no date on the actual unit.

Also the Cirrus chute has two components, each with a potentially different date and a different way of counting the 10 years: the rocket and the chute (IIRC).

And Michael’s example of issuing the certificate only when somebody orders the propeller is obviously a sham practice, although someone could argue that if the prop sat on the shelf for only say a year, it will be fine. But if it really sat on the shelf for just a year, who would be bothered about that date being on the certificate? It smells no matter which way to spin it.

There is also a really interesting angle on this in the Lycoming SB569 crankshaft saga. I have some notes from when I did mine here. At the end:

But that’s not the same as a hydraulic pump which has various seals inside. The Lyco crank issue was not related to anything actually (in the physical sense) life-limited in the engine i.e. the crankshaft was not gradually decomposing and needed a 12 year life limit It was a legal maneuver, implementing the 12-year manufacturer-invented engine life limit, which many thought at the time was done to sidestep a class action (because Lyco offered a free crank if you sent the engine for an overhaul to them within the 12 year period).

It turns out that the Turkish pilot mentioned in the OP unwittingly bought the pump from some “wheeler dealer” in Arizona who deals in unwanted aviation parts. No normal person would have been aware that really nobody should buy anything from such a source without getting a lot of details e.g. photos of the unit and the paperwork… It was basically a kind of “aviation Ebay” outfit. As a final joke, this firm offered to generate fresh paperwork for some small sum like $100+. Very sad…

Administrator
Shoreham EGKA, United Kingdom
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