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What is "infrequent use"?

I fly my plane every 2 weeks. In the 5 months I’ve owned it, I’ve averaged 8- 10 hours/month. The reason it’s every 2 weeks is because I live 1000 miles from the plane. Every 2 weeks I fly it 4-6 hours. Are those 2 week breaks all year long likely to cause a problem, or is that frequent enough to keep the engine in decent shape?

Tököl LHTL

If you don’t fly it just around the pattern but run the engine under high power for prolonged time, that’s more than enough IMO.

My partner and me don’t fly our plane more than you – rather a bit less – and in general I think most private aircraft see much less use.

Last Edited by blueline at 03 Oct 17:51
LOAN Wiener Neustadt Ost, Austria

This is exactly my pattern of usage – About 120 hours per Annum in a PA28 – 181

I try to fly it every week even if it’s just for an hour but as I’m often away on business, sometimes it stands there for 2 weeks (and recently 3 weeks).

I worry about my Lycoming Camshaft rusting and you have just reminded me to read Peter’s thread about Camguard as this is something I probably need to add to my oil!

At present I have 550 hours on the engine, a recently installed JPI EDM700 and I’m trying to go down the Mike Busch “Manifesto” route – I am not going to kill a good engine so if I can avoid prop strikes etc, I’ll let you know in over 1500 hours time!!??

Thanks – Archer-181

United Kingdom

Every 2 weeks is fine, for about an hour to make sure the water gets boiled out of the oil. Sometimes (rarely) I don’t fly for 2 weeks, due to work, hassle, etc.

The issues with “hangar queens” in GA are much much much worse than 2 weeks. Yesterday someone emailed me about a plane that had not flown for 10 years. The engine was finished… Planes that don’t fly for a year are common too – just take a walk to your nearest airfield. I have shared hangars with all kinds, up to a 421C which flew maybe once a year, between the £20k annuals. Another was a piston helicopter; the owner turned up in a Porsche and nice sunglasses and took it for a spin, once a year (a big cloud of red smoke out of the exhaust). You get homebuilts which were built over 30 years, the engine installed somewhere halfway, etc… The seller will probably change the oil+filter immediatley before the sale Socata built a load of TB20GTs with rusted-up engines – stored for way longer than the max allowed by Lyco (1 year) – and a number of owners got a “surprise”… luckily by now all affected ones will have had the SB569 crank change so, provided that was not done by a cowboy, they should be OK. Mine (a prop strike in 2002) was done by a cowboy… related to an outfit which assembled propellers out of condemned parts with fake 8130-3 forms

This issue is really endemic, much bigger than most people would believe, and every case I have heard of involving an engine with shagged cams / followers was one where long periods of inactivity were either known, or could not be ruled out (under previous ownership, missing logs, potentially forged logs, etc).

The less obvious thing is that avionics suffer too. I guess it is damp getting in and not getting driven out.

Camguard is a total no-brainer, for the £25 bottle every 50hrs. But it probably won’t help if you leave the plane for months.

OTOH there are known data points of engines sitting for years with no corrosion, but the ones I know about are middle of the USA. I would think Arizona would do nicely. Old abandoned mining equipment there looks great after 150 years in the open air.

Administrator
Shoreham EGKA, United Kingdom

On a side-note: how bad would a non-active period of several months be for my Rotax 912? I suppose the issues would be similar to other engines, though, so the answer must be similar too. Even if there are differences on other points ( cooling, electricity, ignition, … ), regarding lubrification the Rotax doesn’t differ much from the US’an boxers.

EBZH Kiewit, Belgium

Peter wrote:

Yesterday someone emailed me about a plane that had not flown for 10 years. The engine was finished…

But sometimes you can get lucky.

There’s a guy on reddit r/flying who bought a Cherokee for $1000 that had been sitting outside for over 10 years in Charlotte NC (which is somewhere that’s pretty green and humid – I spent 6 months in NC and know that it can’t be described as “dry”). While it was very scruffy and looked completely shagged, but it turned out to be in remarkably good condition and has been the subject of an AOPA article.

It remains to be seen how long the engine will last now it’s running again, but the engine wasn’t toast, surprisingly. I had expected him to need to overhaul it as the first job.

http://www.thisoldcherokee.com/

Andreas IOM

It remains to be seen how long the engine will last now it’s running again, but the engine wasn’t toast, surprisingly

So long as it turned around enough to start running, it will keep running None of the Socata engines actually seized up… well, one almost did in flight, according to the owner who I know, although at the time he wasn’t aware of the likely reason. The piston rings will scrape off most of the rust, and the various bearings will rotate ok because 200HP or whatever is an awful lot of torque

The update on this blog entry

will be a useful data point. One would not find rust in his oil filter. What you see in the oil filter is metal particles which are small enough to pass through the sump strainer, but big enough to not pass through the filter (in my Lyco, anyway). I think the only bigger stuff in the filter will be gears in the oil pump breaking up. Camshaft/tappets etc will not reach the filter if the fragments are big.

As I said earlier, there are contrary data points, and I don’t think anybody knows for sure the reasons. But the vast majority (especially of the people who are the most likely to be operating in this scenario) don’t do oil analysis anyway…

Regarding a Rotax, I have no idea about them, but one reason put forward for car engines not corroding readily is that the sump breather is fed back into the inlet manifold (so the engine burns up any muck coming out of there) and is thus a lot less exposed to fresh air. And of course nobody does oil analysis

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

Regarding a Rotax, I have no idea about them, but one reason put forward for car engines not corroding readily is that the sump breather is fed back into the inlet manifold (so the engine burns up any muck coming out of there) and is thus a lot less exposed to fresh air.

The Rotax doesn’t have that much in common with car engines either. It has dry sump and dumps (too much) oil through the breather over board as well.

EDLE

I think the Rotax may have more in common with my motorcycle engine, which also has a dry sump and was made by Rotax!

Andreas IOM

Ok, so is use once a month for two hours infrequent? Or what are the maximum intervals of non use you can get away with over a long period of time?

Tököl LHTL
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