[Cowshed]

I’ve had my ‘licence to learn’ for a couple of year now, but realise I know very little about the maintenance rules associated with GA aircraft. At the moment I rent. You hear the phrases 50 hours check, annual, time between overhaul, on condition etc.

I have picked up a bit by osmosis over time, but no one has ever sat down and explained in general terms what is required and when (on reflection that is my fault for not asking).

I appreciate permit to fly aircraft are different, and I’m aware of the Self Declared Maintenance Programme which I understand can’t be used by anything deemed to be a commercial operation (such as a flying school).

I guess the details are as opaque as licencing, but does any kind hearted forum member feel they can summarise this subject?

Apologies if this subject has already been answered in other threads, but if so I haven’t managed to find anything that fits the bill so far. Thought I’d stick this post in the Student area as it might be useful to other new-ish PPLs and students.

[flybymike]

Great question but might require a long answer!

[Crash one]

Not knowing your reason for wishing to know the details, it's difficult to answer.
However.
An aircraft with a Certificate of Airworthiness effectively means that the pilot/owner is not allowed to carry out very much in the way of maintenance, check tyre pressures, clean plugs etc, little else. Whether the aircraft is owned by one person, flown by the owner, solo, or operated by a flying club and rented by anyone, carrying paying passengers.

Permit aircraft you can do all of the work, provided you get the work signed off by your grown up certified engineer/inspector. Commercial ops not allowed.
Usually limited to two seats and annex 2 types.
Hence a vastly less expensive way of owning an aircraft. And usually results in the pilot being more confident in the aircraft based on "It's my ass that it is strapped to", rather than "Get that thing finished by Tuesday, the owner wants it in a hurry".

I have a permit aircraft so I am not familiar with the CofA regime except knowing that all parts fitted must be traceable to the nth degree, certified, paperwork, etc etc. Expiry dates of annual, 50hr checks etc must be adhered to and so on.
As a result, push it in the hangar, throw you bank/mortgage details after it and wait till they tell you what they have done and how much in debt you are!
As you may have guessed I am somewhat biased, sorry!
Any use?

[cockney steve]

As stated, Certified, similar situation to that which (you think) applies to a car....IE a manufacturer- approved servicing and repair regime using only stuff which is approved by the manufacturer and the regulatory regime (even if there are better, but uncertified substitutes on the market)
Permit aircraft, as stated...uncertified parts are the norm. but your LAA inspector isn't going to be happy with the 1/4 whitworth bolts from granddads shed, even if they're still wrapped in prewar waxed-paper!
Should you be using modern H.T. bolts the strength -code should be on the head. no traceability, but if bought from a proper engineering-supplier will be perfectly acceptable.
Yes, you can do all sorts of building/rebuilding/repairs, subject to prior approval and stage- inspections by your LAA inspector.
AIUI, If you can find a cooperative approved repairer, it is possible to do or assist in work on a Certified aircraft, but essentially, the person in charge of it is putting his name and licence on the line.....they must know you well before letting you loose!

Note I'm not a pilot but have lots of mechanicking, tin-bashing and general engineering and fettling experience.


PS There are 4 seat permit- types about.

[Flying_john]

A starting point is:-

http://www.peter2000.co.uk/aviation/faa-nreg/easa-owner-maint.pdf
Sorry might be a dated version, but search for MPart M pilot maintenance.

Also if you can find a friendly engineer who will supervise and sign off your work, or allow you to "help" with maintenance, then a good learning opportunity and save some cash too.

[Cowshed]

Thanks for the thoughts and comments. My interest is purely out of curiosity at the moment, though if I join a group I hope to learn by getting more involved with the process.

My extremely simplistic summary is that a C of A aircraft needs to be maintained by a maintenance organisation which will inspect/service/change the components making up the aircraft in line with the manufacturer’s instructions – e.g. every 50 hours, 100 hours, 200 hours, annually. These instructions may, in turn, vary slightly depending on how much the aircraft is used and how it is used (e.g. for hire).

…or is that far too simplistic?

I’m beginning to see that there is a lot of detailed knowledge required about each aircraft type, and that there isn’t a generic set of rules for typical GA aircraft.

[Miscellaneous]

Thanks for the thoughts and comments. My interest is purely out of curiosity at the moment, though if I join a group I hope to learn by getting more involved with the process.

My extremely simplistic summary is that a C of A aircraft needs to be maintained by a maintenance organisation which will inspect/service/change the components making up the aircraft in line with the manufacturer’s instructions – e.g. every 50 hours, 100 hours, 200 hours, annually. These instructions may, in turn, vary slightly depending on how much the aircraft is used and how it is used (e.g. for hire).

…or is that far too simplistic?

Yip, too simplistic in assuming it will be done to any better a standard than non certified engineers' IE an LAA inspector, or syndicate member.

I’m beginning to see that there is a lot of detailed knowledge required about each aircraft type, and that there isn’t a generic set of rules for typical GA aircraft.

It may well seem that way from outside looking in, buy a share, get involved and with the proviso that you are mechanically minded you will be surprised how more straightforward it actually is. You do also require a heavy helping of common sense, primarily to know when to call an inspector.

[Crash one]

The basic build of an average spam can club/school aircraft is very similar to a classic car of 50s/60s.
Nothing complicated about them.
If you join a group with a CofA aircraft the chances are you will learn nothing much about the mechanicals probably because the rest of the group will be schit scared to even remove the engine cowling for a look inside.
A group near me don't even know where the battery is fitted!
During flying training I asked the maintenance "engineer" what he thought of permit aircraft.
"Put one of them in our shop and we'd never let it out the door again, too many uncertified bits on them." Whilst at the time using a pair of pipe fitters pliers to tighten nuts on the carburettor!!!
Then, one of the school Cessna 152s the beacon light fell off the top of the tail, hanging by its wire, someone lashed it back on with Duct tape, flew it to maintenance to get fixed.
Next morning it was flown back, they hadn't even painted the Duct tape!!
A nose wheel oleo leg collapsed, oil leak. Flown carefully to maintenance, returned next day, oleo leg collapsed on landing.
A friend of mine. CofA 152, group owned. Vacuum gyro compass not working. Maintenance replaced unit, three weeks, £800, it still didn't work!!
My aircraft, vacuum gyro compass not working, same symptoms. Two hours work. Removed, stripped, cleaned, pipe work replaced, refitted. £5.45 including buying a mini pipe bender. Works perfectly for the last 5 years.
Yes there are far better maintenance outfits out there, these are just my experiences, although I don't think I'm alone.
If it ever becomes law that permit aircraft must be maintained by certified engineers in certified premises, I will give up flying in the interest of self preservation.
So I'm not the person to ask about maintenance schedules, part M or any other part.

[Paul_Sengupta]

This is all well and good, but to answer the question asked...

Back in the not too distant past, there was a fairly standard scheme for maintenance of light aircraft. This was known as LAMS, then something else, then LAMP. This consisted of a large inspection called the annual inspection, which unsurprisingly happened every year and various interim services/inspections. Under the older system, there was a thing called a "star annual" every three years which was an additional amount of work for a C of A renewal.

Interim services/inspections were at 50 hour intervals or six months, whichever came sooner. This was the same inspection at 50 hours and 100 hours, but then at 150 hours there was a large service/inspection, not too far off an annual inspection. If an aircraft flew 300 hours a year, it was worth doing this. If it flew 180 hours a year, it was then worth bringing the annual inspection forward instead, rather than repeating the large service after 30 hours.

On top of this are service bulletins (SBs) and airworthiness directives (ADs). The ADs were/are mandatory, the SBs were not, though EASA muddied those waters by introducing Part M which required a whole load of unnecessary maintenance and replacements for SBs and lifed other parts using arbitrary time or hours measurements. SBs and ADs are specified per aircraft depending on what's been found to require additional inspections or replacements. The inspection intervals for ADs may or may not coincide with other inspections, but are normally done while in for scheduled maintenance.

Back in the day there were two main classes of C of A, private and public. For commercial work, including aircraft hire, the aeroplane had to have a public category C of A. On a private C of A, more work could be done (i.e. signed off) by the owner. This was later changed to a single category, but with the stipulation that the aircraft could only be used for aerial work if the last service was done to certain rules by certain qualified people. Part M also introduced the requirement that the engine be within calendar TBO as well as hours TBO to be used for aerial work. It used to be the case that you could have up to two TBO hours extensions of 10% each, so a maximum of 20% on a public category C of A. On a private C of A you could run the engine "on condition" indefinitely. I'm not exactly sure what the latest rules are now on this, but you can still run the engine on condition if it's only to be used for non aerial work purposes.

The other part of the equation which EASA Part M brought in was the "controlled" and "uncontrolled" environment. It was said when this was introduced that the controlled environment would mean all annuals were just annuals, but you paid a maintenance organisation (or someone else!) to be a CAMO and look after your paperwork. It was then said that in the uncontrolled environment, without a CAMO, each annual would be akin to the old star annual. In practice I don't think this has worked out this way.

This has all been changed around a bit recently with the self declared maintenance programme (SDMP). Quite a lot of what I've written above doesn't necessarily apply any more, and the maintenance can be tailored to each specific aircraft, based on manufacturer's schedules or any other reasonable maintenance schedule as far as I've quickly glanced at what people have said on the forum! You're going to still have the annual inspection, and it's always good practice to change the oil and filter every 50 hours at least, so you can work on that sort of schedule. I believe many people have just chosen to use the old LAMP as the basis of their self declared schedule, but that's just hearsay on my part.

Some of this may be wrong, as I've just written this off the top of my head, and I'm sure people will correct it if it is!

I hope that gives a bit more information towards the answer you were looking for!

I haven't mentioned avionics annuals but they are in there somewhere. Maybe.

[johnm]

Paul is pretty close, but the 50 hour can be done by the pilot on a C of A aircraft and we usually do ours as it's an opportunity to have a good look round the aircraft.

LAMP still applies to ELA2 aircraft but ELA1 have been on SDMP since last September.

“ELA1 aircraft” an aeroplane with a Maximum Take-off Mass (MTOM) of 1 200 kg or less that is not classified as complex motor-powered aircraft;
“ELA2 aircraft”) an aeroplane with a Maximum Take-off Mass (MTOM) of 2 000 kg or less that is not classified as complex motor-powered aircraft;

[Morten]

Good stuff, Paul (et al)

Going over to the other side and tbe PtF route, can these be used for "aerial work" in the sense of e.g. pleasure flights or would that then require maintenance beyond the norm?
E.g. can you operate a Jodel or an RV for something akin to the french baptême de l'air - and take payment for that beyond the operational costs - or would that require a CofA aircraft or a different maintenance regime ? (nevermind tbe pilot's license for now)

[Paul_Sengupta]

Paul is pretty close, but the 50 hour can be done by the pilot on a C of A aircraft and we usually do ours as it's an opportunity to have a good look round the aircraft.

Yes, though as mentioned above, you can only do this if the aeroplane isn't going to be used for aerial work in the subsequent 50 hours.

Well, you can, as you can do any work, but it would have to be signed off by a licensed engineer.