This FAA doc lists Socata P/N TB2061238001 (a 1600psi landing gear pressure switch) with this description
It has been established by at least one very diligent TB20 owner I know that Eaton had quality problems with this switch. It is a part used in a lot of retractables. It is of not particularly great build quality but as with so much stuff in GA once it is approved in one place it gets used elsewhere…
I understand Eaton fixed the design c. 2008.
The OEM P/N is 211C243-28
Just replaced this switch on my TB20…
The intermittent UP operation disappeared immediately.
I will post some videos on the old TB20 landing gear thread when I get them uploaded.
Eaton seem to have produced a bad batch of these switches, over about a 10 year period. They go loose inside and operate intermittently at much lower pressures than the rated 1600psi one. By “much lower” I mean something like 50psi!
Peter wrote:
Eaton seem to have produced a bad batch of these switches, over about a 10 year period. They go loose inside and operate intermittently at much lower pressures than the rated 1600psi one.
And their punishment for that is that they have the opportunity to sell another switch to you! Certification regimes are the most socialist and anti-market thing there is. Giving out monopolies to vendors and thereby reducing quality.
Yes – very bad.
There are loads of these switches on the market, at around the €200 mark for an aerospace-grade switch (this Eaton one is a crappy sub-automotive-grade one). I found it not easy to find a 1600psi one which had the same thread on it, available with a short lead time. So I bought a replacement Eaton one from Socata…
However, as with most aircraft parts, if you can get a functional replacement and it comes with a CofC, you can use it (on an N-reg, for sure). The key words are a “basic change to” the hydraulics.
So the people who get shafted are the EASA-reg ones, and those who have to use a maintenance company which refuses to read the regs (possibly because the margin on a €1300 switch is worth having).
The whole crappy system is supported not just by the certification system (which always gets the blame for it) but equally by financial motives within the “aviation” parts supply and maintenance industry. 30% of €1300 is a lot better than 30% of €200, especially if you are getting say €500 for the installation labour. If there was a clear concession allowing parts substitution, large areas of the restrictive practices would collapse.
There are such concessions but very few people know about them because they are interpretations of the regs rather than explicit words.
The FAA’s PMA scheme (which has no EASA equivalent) goes a part of the way but not much because getting a PMA requires a lot of proof which nobody bothers doing except on parts which move swiftly, and the new part is near-identical which exposes the vendor to a copyright action, not to mention the preceeding difficulty of proving the part is the same when the design data was never published…
Peter wrote:
and the new part is near-identical which exposes the vendor to a copyright action
It can’t. You can’t copyright a device or a circuit or something like that. You can copyright a drawing of it but not the actual part. You can patent it, but patents have relatively short terms (on the order of 20 years) and the patents on most stuff in GA has long since run out.
alioth wrote:
You can patent it
Not even that. You can only patent a part if there is some innovation in its function. (In principle, that is. Patent offices these days are known to patent anything that hasn’t a previous patent.)
There is truth in all that but the reality is that if you just copy a successful product you will invite litigation.
The world is full of people who will have a go at you and some have loads of money.
Otherwise PMA would be easy.
