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-   -   12 Year Limitations on UK Piston Helicopters (https://www.pprune.org/rotorheads/582293-12-year-limitations-uk-piston-helicopters.html)

carlmeek 31st Jul 2016 08:46

12 Year Limitations on UK Piston Helicopters
Please can someone explain to me precisely what happens when a piston engine gets to 12 years old in the UK? I've heard that it's no longer allowed for rental/training - but i can't find those rules written, and just want confirmation. Also - if anyone has any experience on what this means in real life, and whether I should consider this as a key criteria when buying a machine.


Palma 31st Jul 2016 09:04

What you have "heard" is incorrect....

ScotiaQ 31st Jul 2016 10:12

Piston Engine Restrictions
Any finite life or restrictions will, usually, only be imposed by the Manufacturer (OEM). They are usually listed in Chap. 4 of the Maintenance Manual but sometimes in Service Letters, again published by the OEM - of Engine or Airframe.

Any restrictions imposed by the Airworthiness Authority will usually be promulgated in the form of an Airworthiness Directive (AD)

lowfat 31st Jul 2016 10:14

you might have "heard" about the 12 year life of the Death egg or Robinson 22 as it is also known

which is enforced regardless of country

Gustosomerset 31st Jul 2016 10:18

I hope my research on this might help....but please don't take this as definitive. No doubt there are others here that will understand this issue better, but this is my attempt at understanding the regulations:

A helicopter piston engine is said to be being maintained ‘on condition’ when the engine (whatever its hours) is outside the 12 year + 20% rule, after which the engine must normally be fully overhauled. This means it can only be used for ‘private use’ - for airworthiness purposes and not for ‘public transport’ or ‘aerial work’.

The regulations that I have found that relate to this are as follows:

1. Air Navigation Order 2009 Paras 3.1.1 and 3.1.2

"A flight is for the purpose of aerial work if payment is made in respect of the flight or the purpose of the flight, unless the flight is in fact for the purpose of public transport. If the only payment involved is the payment of the pilot, the flight is deemed to be private for airworthiness purposes (although it will still be aerial work for other purposes, e.g. flight crew licensing). This enables a private owner to pay a flying instructor for a flying lesson in the owner’s aircraft even though the continuing airworthiness requirements that would be applicable to public transport aircraft may not have been applied. “

So, as I understand it, so long as the aircraft is privately owned, then the owner can pay an instructor to train him or her on it whilst it is being maintained 'on condition'. So far so good.

2. Air Navigation Order 2009 Paras 6.5.2, 6.5.3 and 6.5.4 - Jointly Owned Aircraft

"An exception has been established so that the continuing airworthiness requirements applicable to public transport aircraft do not have to be complied with. This is provided -

(a) payments are made by members of the group to a central fund which amount to no more than direct and annual costs of operating; and
(b) the group comprises no more than 20 persons (each with at least 5% share) whose names have been notified to the CAA.

This exception applies whether the aircraft is jointly owned directly by no more than 20 persons or by a company which is owned by no more than 20 shareholders. The shareholders must be individuals and not companies. It should be noted that this exception can only be relied upon if the only payments are those made within the group relating to the direct and annual costs of operation. No other payments can be made if it is wished to rely on this exception. In particular, a member of the group cannot pay an instructor to train the group member in the group-owned

So the same aircraft could be owned by a company or group, with up to 20 shareholders. But any member of the group cannot rent it out or pay an instructor for PPL training. In other words, this seems to say that an owner could only pay for instruction on the aircraft if he/she was the sole owner of it (point 1 above) but not if he/she is a joint owner.

I hope this may help!

Hot and Hi 31st Jul 2016 10:42

That is not true, low fat. Many helicopters, including Airbus, Robinson, need to undergo a 12-calendar year inspection, regardless of hours flown during that period. Once they are beyond the calendar limit, they are simply not airworthy (not limited to 'no training') until that maintenance job is done.

Once the inspection is done, they are released to service again. What carlmeek reports, if at all true, is about something else.

Also, guys, please don't confuse the Robinson 12-year inspection with the Robinson 2.200 airframe hour overhaul. The 12-year inspection is a relatively small subset of the 2.200 HR overhaul.

carlmeek 31st Jul 2016 11:01

My question is really specifically about a lycoming engine in an enstrom airframe. I have been told by a UK instructor that after 12 years they can no longer rent or train in the machine.

I googled and found this which agreed with this back in 2009


I'm not sure how to find out for sure! I'm trying to decide how important this is to me, and when I come to sell the machine once I'm done: and how much this factor should impact the price.

On a personal level I'm also pondering whether a 25 year old helicopter with original engine is a good thing or not!

Self loading bear 31st Jul 2016 11:30


If you read answers in the forum you mentoined you should have your question answered.


carlmeek 31st Jul 2016 11:58

I did read that post... but that was 2009, and there is more than a suggestion this might not be correct - for example the first reply to this thread!

Ideally i was looking for the actual words of the law rather than heresay, to make a sensible assessment over whether it should be a requirement in purchasing a new machine, or not.

FLY 7 31st Jul 2016 14:02

Gustosomerset's answer appears to give you chapter and verse.

If you are quantifying the cost of a 'zeroed' engine, a Lycoming rebuild is c.20,000 ($28k).

For comparison, the 15 year overhaul on a Turbomeca Arrius 2F is more than 10 times that figure :eek:

Gustosomerset 31st Jul 2016 23:08

Hi, as Fly 7 says, I hope my reply gives you the answer you need. As far as I can see, you can pay to be instructed on an aircraft in which the engine is beyond the 12 year limit and is therefore being maintained on condition. But only if you are the sole owner of that aircraft (bizarrely).
However, in no circumstances can it be rented out to others for financial reward. Note, I'm referring here to the 12 year rule as applied to, for example, the Lycoming engine of an Enstrom or Hughes 269 (which is how I understood your original question) not that applied to the airframe of a Robinson....which is a whole different issue.

Gustosomerset 1st Aug 2016 08:22

Carlmeek - so, looking again at your original and subsequent questions (sorry), my understanding is:

1. "I have been told by a UK instructor that after 12 years they can no longer rent or train in a (Lycoming engined Enstrom) machine".

It's true that they can't rent such a machine to you or train you in it if the engine is beyond its 12 years (+20%) life - if they own it. But if you own it - on your own - (which I assume is your intention as you talk about buying a machine) then they can train you on it whilst the engine is maintained 'on condition'. You or they cannot, however, rent it to anyone else.

2."Should I consider this as a key criteria when buying a machine?"

Yes - but the effect on value depends on what you want to do with it. If you want to rent it out or allow others to be trained on it, then you will have to have the engine 'zeroed'. However, if you only want it for personal use or to lend (not hire) it to others - and so long as the engine is good enough to be maintained on condition - then you can continue to fly it on that basis. As Fly 7 says the engine rebuild will likely cost 20k to 25k - so this should affect the price you negotiate.

Hope this answers the question.

krypton_john 1st Aug 2016 09:44

Am I missing something? Are you saying in the UK the 12yo engine can't be given an approved rebuild and another 12 years?

There certainly are plenty of perfectly good Enstroms older than 12 years flying around.

lowfat 1st Aug 2016 10:51

you are getting mixed up with air transport regulation and private airworthiness.
If the machine is used commercially buy a business then at 12 years the engine must have an overhaul and be recertified .
However if the machine is not used commercially its service life becomes "on condition" ie it can remain in service so long as it performs correctly, passes inspection and any faults can be rectified.
in this instance a flight school can not operate a machine that is not air transport.

Once the engine is overhauled it has another 12 year commercial life.

A zero time piston engine may have few components left from its previous life.

Gustosomerset 1st Aug 2016 11:25

Lowfat - exactly. You're quite correct that a flight school cannot operate a machine that is not air transport. But an instructor could teach someone on their own aircraft that isn't (subject to all of the provisos that you point out regarding operating 'on condition'.)

carlmeek 1st Aug 2016 12:00

Gustosomerset - Thanks, that's really clear :)

NutLoose 1st Aug 2016 23:59

Cap 747 GRN24 which is page 346 on link below, is the book of words on the subject and the limitations etc. AND WE ARE TALKING UK REGISTERED HERE

CAP 747: Mandatory requirements for Airworthiness

Just to clarify Lowfat's comments, an overhauler cannot actually "zero time" an engine, only the manufacturer can do that, though an overhaul agency engine does come back in effect with nil hours and the full life cycle to run again.

You can get engines out of the factory that on the log book cert record the engine hours at as an example, 5000 hours plus, as they may have been overhauled twice and not zero timed, IE they have been overhauled to Overhaul engine limits and tolerances and not new build limits and tolerances.
Been there, seen it, and done it with the CAA, who were querying a factory overhauled Lycoming with 2780 hours on the release cert certificate and why was I fitting it!.
Even if an outside overhaul agency overhauls it to new build limits btw, he still cannot call it zero timed, but might sell it as say Diamond standard or gold standard etc and state that it is to zero timed limits.

There are three basic types of Factory engine,

New Build as it implies, new.
Zero timed as said to New specs.
Overhauled as said to overhauled limits

As for the 12 year rule on school aircraft, that is semi incorrect, the engine life as with the hours is also able to be extended in the UK under GRN24 up to a maximum of 20% subject to the engine performing and meeting certain inspection requirements.

hope that helps :)


Palma 2nd Aug 2016 08:00

12 Year Limitations on UK Piston Helicopters

I have sent you a PM.

bvgs 11th Aug 2016 08:31

I was told some time ago that under the Austrian register, you can fly a Robbie past 12 years as long as the 2200 hours hasn't been exceeded. They quote an FAA regulation on this. The company was Star Trade Heli who are a very reputable company. Has anyone else heard this?

chopperchappie 14th Aug 2016 17:51

I quote flyq "most helicopters fall into the category of "pay now" or "pay later"" !
To paraphrase - either you spend money upfront now to buy/overhaul or you spend money later in repairs or reduced residual value.

In line with others before in this thread - I would much rather spend money upfront and know that I am flying something as airworthy as practical.


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