A very interesting article from Mike Busch has popped up in email.
Peter wrote:
A maintenance company I used to use would not allow any of their people to fly in the plane
While noting the smiley I recall post operative flight after the prop. governor had been overhauled. I persuaded (I think for the first time) the chief engineer to accompany me. Well we barely climbed away because the prop would not go fine, so next time they carried out a static strobe test. It was an interesting experience.
Whether there is an increased possibility of things going wrong after maintenance – well I suspect the answer must be yes, because after “disturbing” anything mechanical there must always be a chance something else has been disturbed or not correctly refitted.
Yes. Both after maintenance.
The air leak was at the mechanical pump, following it being opened by an aviation mechanic at an Annual Inspection, before going on Permit. That Jodel had a fuel pressure gauge, but nothing showed on first flight, which I flew. Later, a flicker of the fuel pressure gauge needle when on rear tank was reported. I was pax on next flight, and nothing odd was noticed. I then climbed on rear tank until engine lost power.
The incident last summer followed fitting a replacement inlet pipe to the fuel pump. No fuel pressure gauge fitted. I flew the LAA AirTest without any problems.No Aviation Engineer involved, except check after work. Next flight, the problem showed up. The Inspector, ex Air Force engineer, fixed it by work on the pipe inlet fit.
It really depends on the nature of the work. But generally for things like post oil/filter changes, after doing a ground run, I’ll fly solo for about half an hour, land, and re-check for any evidence of leaks. Work on the fuel system? I want a good hour or so of flight time with a decent long climb in there to verify there’s nothing wrong with the fuel flow, including a climb on the aux tank (which is not gravity fed). Permit aircraft like Maoraigh.
Not so much as a no passengers (I’ll take another pilot) or no overwater – even if I had no overwater flight to do ever – for instance when I was living in the United States and had the Cessna 140, I would want to do at least one local maintenance check flight. More of “I want to do a bit of local flying and make sure everything works, before heading out cross country” type of policy rather than overwater specifically.
I’m more than happy to fly any aircraft after maintenance that I’ve been involved in.
Whether or not I’d choose to fly with many of the owners/pilots is a completely different matter….
PS Maoraigh – were the two issues you cited as a result of the preceeding maintnenance?
On a Permit aircraft, where we do most of our own work, flying with a Group member as pax wouldn’t count as carrying a passenger. I make a point of climbing steeply on rear tank, after switching off electric pump, which has on two occasions lead to a request to return for early landing.
Both post maintenance, but not first or second flight.
One air leak at mechanical pump, the other, in 2016, fuel leaking at pump.
We don’t have a fuel pressure gauge.
If everything OK, I’ve no worries about where I go after maintenance.
Great story, @huv, and many thanks for posting it. BTW I wonder how long the overhaul outfit ran the engine on the dyno? But even that may not have revealed the problem, if the avgas tank was high enough.
But there must be a scale of acceptableness.
Yes of course. The seat belt etc I would not be concerned about. But any access behind the instrument panel has potential for stuff – even leaving a screwdriver there which jams the controls later. I never fly the plane post-service unless I have personally inspected under all the access panels: the two panels at the base of the windscreen, and the two belly panels if they were removed.
Huv’s story relates to a different aspect which is how much you trust the company doing the work. That must be a factor for any owner… syndicates tend to have less choice (the only agreement will be on the lowest quote, I guess). This is why I am happier to have an engine built by a known-reputable US shop than by any European shop. I have hundreds of emails detailing similar experiences. One UK pilot had his engine buggered by a top overhaul (they left something inside) and they then buggered the overhauled one again. But, being an admin here, had I posted huv’s story myself I would be slammed here for slagging off maintenance shops etc etc etc – often by the same people who earlier told me stories of their own disasters 
@huv: that’s a good story, we can all take our lessons from it. Thanks for sharing!
Our TMG had its engine overhauled last year and it was returned and installed shortly before Christmas. I then flew it half an hour close to the airport at different lever positions and observed what could be observed. On the next flight I flew a 1-hour local flight away from the airport, but always within easy reach of reasonable off-airport landing sites.Then we inspected the engine, found nothing that was not spotless, and “declared” it “released” to the syndicate, and a fellow pilot flew a short local trip just before sunset, while I drove home. When I got home he called me and said the engine had failed close to the airport but not close enough, and had landed in a field and the TMG momentarily stood on its nose because the field had been a little soft, as most fields were in December whenever they were not frozen.
The next morning I put on rubber boots and met in the field with the pilot and an AAIB representative. We scraped the mud off the prop and spinner and started the engine without problems. When we switched off the electric fuel pump, the engine lost power and stopped after a short while.
It turned out that the newly installed mechanical fuel pump had been installed incorrectly, using incorrect parts, and it did not produce enough fuel pressure to keep the engine running. When I had flown the plane, the fuel level had been high enough in the tank so that very little pumping was required to feed the engine. As the fellow pilot took over the plane, it seems that the fuel level had lowered just enough that the pump pressure was insufficient to keep the engine running. The poor soul had been at a rather low altitude, busy talking to talking to ATC, looking for other aircraft, and trying to remember cockpit-flow-procedures in a plane had had not flown for some time, and forgot to switch on the electric pump. He kicked his own behind for that afterwards – however, his landing had been good, and in the end no damage was found other that a slightly bent wheel fairing.
I guess this just confirms that on the third flight after overhaul you are still on the high part of the failure rate curve.
But there must be a scale of acceptableness. What if a rear seatbelt had been replaced? Or (reductio ad absurdum) the battery replaced in a rear headset, or database replaced in GPS?
