A separate issue is that MM and MM/Limitations issues are sometimes a factor driving people to buy and operate airframes that were certified long ago when airframe MMs were more rudimentary.
That does indeed seem to be true. Just like POHs, also MMs seem to have become more and more detailed and onerous with time.
However, as long as most of the stuff is in the discretion of the operator and his mechanic, the amount of necessary maintenance will always be determined by the complexity and the condition of the aircraft, not by the amount of documentation.
Unfortunately in EASA land, a manufacturer can arbitrarily change the MM and introduce new limits which may become binding. It is a nice revenue generation scheme. Safest is probably to buy an aircraft from a defunct manufacturer…
Been there, done that
http://www.eaavideo.org/video.aspx?v=1105297993001
A component which gets an overhaul will have to have documents showing that ALL parts and dimensions were reworked to as new condition.
Definitely not accurate under FAA rules – the most basic work defined as an overhaul is disassembly and verification that all parts and dimensions are within serviceable limits, not new limits. Then of course, given the labor cost to disassemble and reassemble, it often makes sense to replace or rework parts to new limits. However, the US government has no legal right to force you to replace a serviceable part during an overhaul.
So a motor rewind should really be a repair and that is what I´d suggest any day.
This requires the A&P to have access to documentation from the manufacturer that specifies how to repair, the least how to determine that the component is serviceable. Even when it’s a small component such as a valve where an O-ring is leaking, the O-ring can only be legally replaced if there is manufacturer documentation giving a specification of the O-ring. Unless such documentation is available, a pragmatic A&P would do the repair and install the component either without a logbook entry or something innocent.
A component which gets an overhaul will have to have documents showing that ALL parts and dimensions were reworked to as new condition.
Not so. There are for example two sets of dimensions for an IO540: “new” limits, and “overhaul” limits. My engine, 2008, SB569A, was rebuilt to “new” limits (only the exhaust valves and tappets were out, though the valves would have been within OH limits).
I don’t know how universal this is, but an engine overhauled by an EASA145 company will have been rebuilt to the OH limits, not New limits.
This requires the A&P to have access to documentation from the manufacturer that specifies how to repair, the least how to determine that the component is serviceable.
An A&P has the training and authority to determine (within some limits e.g. pressurised hulls get complicated) that a component is serviceable. AC43-13 is a few hundred pages and covers a lot of stuff. This is where the USA differs from Europe. In Europe, the mechanic is assumed to be relatively incompetent (sometimes that is true, as we all know, but the N-reg scene does not have a statistically higher maintenance related accident rate, so whatever Europe is doing is clearly not delivering any value to the end user).
It is not hard to replace an o-ring for example; the dimensions are obvious, and the material compatibility is easy to check. Or you can buy one from the manufacturer and look at the markings on the bag, and document the OEM P/N for others – doing that is quite a popular activity 
This again is where the USA scores massively, with its mountain of standard parts like AN/MS bolts, fittings, etc so often the P/N is dead obvious. Whereas on say a Socata, you never know if some o-ring is a standard part or, more likely, an unusual part made by some obscure French company, 5x the cost of the AN part, which has either gone bust or doesn’t communicate (either because they won’t communicate with foreigners, or because they realise the part is a Socata part – I have just had exactly such an email from Spiragaine, concerning their 40mm vent hoses).
http://www.eaavideo.org/video.aspx?v=1105297993001
VicThat is a video every N-reg owner should watch. All 85 mins of it. Thank you for posting it, Vic.
The closer the plane is to antique. classic, unusual or ‘unsupported’ you can bet the more generic the logbook entry will likely become. What really matters is that the next annual inspection is signed off by the IA, and that technically correct work was done to make it function properly.
The dynamo in our Cessna 140 failed while I was on a trip, and I got it repaired in the field (the A&P that I took it to near Phoenix removed it from the aircraft and took it to a generic motor shop somewhere in the town and they did the work, and he signed it off). And indeed the logbook entry was pretty generic :-)
