Engine calendar life, where mandatory?

Peter wrote:

you are based.

In the USA, the UK, and I think most countries in Europe, you are allowed to run the “old” Lycoming or Continental engines past 12 years, and you can run them to 2000hrs, and then run them after that “on condition” (which basically means compression figures above certain limits, etc).

The scenarios where they can’t be run past 12 years are generally when carrying paying passengers.

In all EASA countries at least, TBO is a recommendation and can be extended under Part-ML.

Thought some might be interested in local flight school experience with twins and TBO, as related to me yesterday by a guy who works on them and inspects them. I think they’re Beech Duchesses, anyway they’re equipped with Lycoming O-360s. They run them now to 1.5 TBO, which means 3000 hrs as normal practice, and given the hours per month that doesn’t take as long as it might. Apparently they ran one to 4000 hrs at which point it threw a rod out of the case. Prior to that their regular examiner said he would no longer fly in it. They then went back to 3000 hrs.

Meanwhile my O-320 is coming up on 51 years since it was originally built, still a mid-time engine, no leaks, never been apart. Oil consumption is stable at between 10 and 12 hrs per quart, good compressions and nothing whatsoever visible in the oil filter when it’s changed. I can’t see a reason to touch it, although I watch it closely.

ErlendV wrote:

Where can I find the different requirements for TBO/calendar times for an engine/aircraft that is to be used in an ATO, DTO or PART-CAT-operations?

Same with the CAMO requirements for ATO, DTO etc… Controlled, uncontrolled. I’m really confused.

You won’t find TBO/calendar time limits as such in the regulations as they are “hidden” in the aircraft maintenance programme (AMP). Part-CAT and commercial flight schools (ATO or DTO doesn’t matter) have to employ a CAMO who makes up the AMP. The CAMO has to follow the rules of their national authority, which will limit the TBO/calendar times to that determined by the manufacturer, possibly with some extension determined by the particular ops.

For private flying and noncommercial ATO/DTO, you can choose between having the CAMO determine the AMP, in which the above applies, or you can make your own AMP in which case you can run the engine on condition indefinitely if you wish.

For non-CAT ops with aircraft with a MTOM of 2730 kg or less, the rules are in part-ML, particularly ML.A.201 “Responsibilities” and ML.A.302 “Aircraft Maintenance Programme.”

Bathman wrote:

Couldn’t agree more. It should be standardised and based on best evidence.

The best evidence no doubt being the 70% of the world’s fleet flying under the FARs…

Interesting on the above post.

I personally think that the failure rate on a Lycoming 0-360 is probably the lowest between 2,000 and 3,000 hours with the following caveats

• It has been regularly used during it’s life (no rust on the cam, cylinders etc)
• RPM tests/ climb tests to show the engine is making good power (indicates no significant cam wear/spalling)
• During the oil change it checked with a borescope – to check all is ok with valves – seating well, no scoring in the cylinder, obviously no rust
• Checking Oil filter that no metal is being made

I might be wrong (I am being slightly provocative) about the 2,000 – 3,000 hour thing, but there is no doubt that the most risky engine is the 0-400 hour engine. The problem is that all of the “good” engines get “euthanased” at 2,200 hours because Lycoming want to make money and sell you a new engine!

I fly over water a lot – give me a well used older engine rather than those planes with new engines that fly once every 60 days or less.

Interesting note I found on another forum from a crop duster owner about TBO on his fleet of PT6’s. I quote:

Yes, we completely ignore TBO. Our planes currently range from 10,000-14,000 SMOH. That said, we do comply with HSI intervals and usually do them as much as twice as often as recommended by Pratt. If you have someone who will treat you right on hots, they can be a good way to save money. In addition to finding discrepancies while there is still time to repair instead of replace, frequent hot sections can be a vital tool in determining if current operating practices are allowing for the most economical outcome.

Our in house limits are currently 1000 hours on starter/generators, 5000 on CT blades, 1500 on hot sections, 5000 on FCUs, High pressure fuel pumps, and power sections. Most every thing else is done “on condition”. As far as cycle limits, we strictly observe them on all rotating components.

The results have been outstanding. Dispatch reliability is nearly perfect and operating expense is only a fraction of what Pratt quotes

Seems like doing more frequent hots is a good strategy for longevity.

on the topic…Austro have increased AE300 TBO to 1800hrs today…

Couldn’t agree more. It should be standardised and based on best evidence.

Its a joke at present.