Maintenance Induced Failures

Michael
Give a good inspection to the gear, very easy to install some bolts in the wrong way, also, many times the 1000h gear AD is not done as it should.
As for MIF I had to replace the whole trim tab mechanism after an annual. The bolts were over tightened so the freedom in the system was lost, as a result, the cables tension rose to a very high level causing the screw (steel) to cut deep into the drum (aluminium).

I often think the most dangerous flight is immediately post maintenance. It is important to do the full checks as they always leave switches in the wrong position and breakers pulled at the very least; sometimes worse. It is very easy to overlook a switch position when you run through the same checks every flight and find everything the same, right up to the day after maintenance….

I agree Neil particularly when you are the only pilot. A particularly tricky one is some maintenance organisations switch the fuel if off on types where that is never done operationally. If you don’t check it can be a short flight.

JasonC wrote:

I agree Neil particularly when you are the only pilot. A particularly tricky one is some maintenance organisations switch the fuel if off on types where that is never done operationally. If you don’t check it can be a short flight.

Ha, I 100% agree! I wasted 20 minutes, removed the cowling, searched like a madman when my engine died shortly after startup for the flight back home. Eventually I found the solution: fuel selector was OFF. As I have a BOTH option, it’s an operationally irrelevant device…

I have had my aicraft maintained by the same engineer for some 20 years now and can honestly say I have never had a moments worry after maintenance. I do a VERY full check when collecting but apart from anything that has been brought to my attention by the engineer I have nevr found anything “amiss”. I surely cannot be alone in this.

You are not alone because you found a trusted person to work with.

I have one too.

What I can say is that I never found a maintenance company that did a completely good job. I have found some which did some jobs well and not others. And some I have written about (but would not name especially after being threatened by one recently) did life-threatening stuff (that was a 145 company with every approval in the book). The problem is that maybe 99% of pilots would not have noticed that, because without looking under the inspection covers (which won’t happen unless you somehow do or participate in routine maintenance, or are very paranoid) you won’t know…

Unfortunately people move on, due to family / financial pressures. My engineer had to get a job fixing airbuses, night shift. 4 days on, 4 days off. The pay is 2x what he got working for a GA company. He still does my stuff but is a bit constrained as to when.

All Comanches.
The 1000h AD has 2 parts the first that talks about the bungees and the other that talks about the bolts, bushes etc. Many shops carry the first only but never the second.

I suspect if modern cars were subject to the same 50 Hr oil changes, annual tear downs and other ‘maintenance’ practices as aircraft, the greater proportion of them would soon collect in some vast car park or have to be sent back for re-manufacturing. It’s just as well that most go 100,000 miles without having the hood opened!

I think the annual inspection requirement could be usefully changed to two years or 100 hrs, whichever comes first. A lot of planes get more wear and degradation every year in the shop than they get in the air, and mostly its unnecessary (as well as potentially dangerous). A well maintained plane does not need a complete inspection every 50 hrs or so, with attendant shop-wear.

@Aveling, I suspect if modern cars could last as long as my aircraft have lasted so far (69 and 44 years) then I would never buy another new car. I’d love that but it probably won’t be the case (time will tell but I’m guessing my current car has probably 3-5 economically viable years left in it at 9 years old and 250,000 km to date)