Sitting idle - how long is too long?

[deyoung]

We all agree that airplanes like to be flown, and sitting idle is bad -- but how long is long enough to start to make a significant difference?

Is it mostly linear; flying once a week is seven times worse than flying every day, and once a month is four times worse than once a week? Or is it (just for example) once a week or more is probably fine, but once a month will see things deteriorating, and so on?

I'm guessing that the main reason sitting is bad is that any accumulated water doesn't get driven off and starts corroding things, and rubber parts dry out for lack of being moved and being lubricated... what else?

Thanks!

 

[frfly172]

Like to fly once or twice a week,works well for me,airplane seems to hold up better that way,rather than sitting idle for weeks or months at a time.

 

[James331]

If you hangar it and pickle it...

I've gone a few months between flights and never seen a issue.

I'm sure someone will be along soon to tell you if you don't fly it every week the engine will fall off

 

[Jay Honeck]

This is a great question, and one that probably has no good answer.

Right now, the previous owner of my new hangar has sold her deceased husband's Maule to a guy. The plane is out of annual, and hasn't been flown in years.

Since I'm now his landlord (he's paying rent to be in the hangar) I've been in contact with the guy. He told me that he was planning on bringing a CFI and just getting a ferry permit for the aircraft, to fly it from Texas to New Mexico.

I was amazed. I think I've got him talked into having my A&P buddy on the field annual it first, then run the engine, and then fly it. After that, my A&P will go over it again, and may even change the oil a second time before cutting him loose. I sure as heck wouldn't just hop in a plane that has sat that long and fly it 1000 miles!

But then, where is the cut-off? IMHO, this Maule is an easy example of a plane that will need some work before flying it, but what if it had "only" sat 6 months? Or a year?

I look forward to reading the responses.

 

[Dan Thomas]

This is a great question, and one that probably has no good answer.

Right now, the previous owner of my new hangar has sold her deceased husband's Maule to a guy. The plane is out of annual, and hasn't been flown in years.

Since I'm now his landlord (he's paying rent to be in the hangar) I've been in contact with the guy. He told me that he was planning on bringing a CFI and just getting a ferry permit for the aircraft, to fly it from Texas to New Mexico.

I was amazed. I think I've got him talked into having my A&P buddy on the field annual it first, then run the engine, and then fly it. After that, my A&P will go over it again, and may even change the oil a second time before cutting him loose. I sure as heck wouldn't just hop in a plane that has sat that long and fly it 1000 miles!

But then, where is the cut-off? IMHO, this Maule is an easy example of a plane that will need some work before flying it, but what if it had "only" sat 6 months? Or a year?

I look forward to reading the responses.

If nothing else, there are likely to be ADs that have arisen since it was last annualed if many years have gone by. That alone (at least here in Canada) disqualifies it for a ferry permit.

Dan

 

[BillTIZ]

Depending on the circumstances, Normally a ferry permit is to get it to someplace where maintenance can be performed. Not 1000 miles for a many year out of annual aircraft.

An IA or A&P(?) needs to sign off the ferry permit that the aircraft is safe to make the planned trip. Normally minimum crew and day VFR only. I doubt there is many A&Ps that would sign off a many years out of annual aircraft for a ferry permit.

 

[BillTIZ]

This is a great question, and one that probably has no good answer.

Right now, the previous owner of my new hangar has sold her deceased husband's Maule to a guy. The plane is out of annual, and hasn't been flown in years.

Since I'm now his landlord (he's paying rent to be in the hangar) I've been in contact with the guy. He told me that he was planning on bringing a CFI and just getting a ferry permit for the aircraft, to fly it from Texas to New Mexico.

I was amazed. I think I've got him talked into having my A&P buddy on the field annual it first, then run the engine, and then fly it. After that, my A&P will go over it again, and may even change the oil a second time before cutting him loose. I sure as heck wouldn't just hop in a plane that has sat that long and fly it 1000 miles!

But then, where is the cut-off? IMHO, this Maule is an easy example of a plane that will need some work before flying it, but what if it had "only" sat 6 months? Or a year?

I look forward to reading the responses.

Sounds like a great plan.

 

[poadeleted20]

Lycoming says not to leave it idle for more than 30 days without going through the engine preservation procedure in Service Letter L180B.

The desired flight time for air cooled engines is at least one continuous hour at oil temperatures of 165°F to 200°F at intervals not to exceed 30 days, depending on location and storage conditions. This one hour does not include taxi, take-off and landing time.

I believe TCM's recommendation is similar for Continental engines. Of course, flying it more often is always better, and I do my best not to let my plane go more than two weeks without flying.

 

[NoHeat]

I think the idea behind Lycoming's one hour of flight is to get water out of the oil. By heating the oil sufficiently, for a long enough period.

Otherwise, if you just wanted to splash some oil around, idling on the ground would be good enough.

 

[poadeleted20]

I think the idea behind Lycoming's one hour of flight is to get water out of the oil. By heating the oil sufficiently, for a long enough period.

Otherwise, if you just wanted to splash some oil around, idling on the ground would be good enough.

That's right, and it's that water in the oil which leads to the problems which happen when the engine sits idle. Which is why you have to either fly it as they recommend or do the preservation process in the SL if you want your engine to last.