Could someone tell me the inspection schedule for a 6000 TTSN MU2-N that is operated under part 91 approx 100 hrs per yr, please? I am interested in the most cost effective way to operate and maintain the airplane.

Thank you,

Robert Tanner

The factory inspection program has hourly and calendar intervals.

Shortest interval is 100 hour, 12 months. A good many owner operators run about 100 hours/year, so they effectively have an annual. If you fly 200 hours/year, then it is two 100 hour and one 12 month inspection per year.

The recurring "big one" is the 600 hour, 3 year. Not really that big, about $4K.

The biggest one is the 7500 hour. Wing demate, tail demate, gear NDT, etc. About $30-40K. Nothing major is ever found, but yet the inspection exists.

I can send you the inspection program document for my airplane. It won't match an N model exactly, but it will give you a feeling of the program. Send me email mikec at ciholas.com with your email address for me to share the file.

I have not felt the need to try and make a special program, the costs are simply low enough. If I did, I'd try to expand the shortest interval to 200 hours, 12 months. That would allow my usage, about 125 hours/year, to still fit in one inspection cycle.

Mike C.

I asked about this once at Intercontinental Jet (the factory owned service center), and they had a program they could help get approved that extended it to about 150 hours/12 months. Which would help some folks in that 125-150 hour per year range. I ultimately didn't do it, and have been at about 100 hours per year myself so the default has been working for me. But... it exists if the 100 hours per year is slightly too confining. If you're at 200 hours per year or more then it wouldn't make sense.

Not saying I'm interested in MU2's as I think they are the most obnoxious a/c on the ground as just about anything I ever heard.

However, just poking around I noticed this one.

http://www.controller.com/listingsdetai ... 383583.htm

I understand that there's about 1,000 hrs left before an engine overhaul is due but at 100-150 hrs / yr, that would be quite awhile yet. I also see that some of the inspections mentioned above could be due but those don't seem like real high $$ items.

What else am I missing? Is it realistic to think one could buy something like this and immediately begin flying it or is it likely to have a lot of high $$ catch up mx required?

Looking at some of the recent flight history, it appears to be flown regularly but the highest altitude flight I can find is only 19K ft. If you're on a 2-3 hour flight, why would you take it higher? Does this particular model run out of juice at 20K ft?

How many days is the plane down for an average 100 hour inspection at ICJ or others?

I suspect many private operators are in the 125-150 hour range, and the 100 hour inspections would be a pain for me... Basically it would mean that the "annual" inspection moves back and month or two each year.

The King Air has the same issue of course...

Robert

I don't know how these engine times lead to approximately 1000 hours till overhauls

Overhaul 2628 SMOH / 4589 SMOH
Hot Section Time 730 / -- / -- / 693 SHSI

I think you would need to look very carefully at the engine history.

When these engines are done I would think you can find some engines with remaining time to bolt on.

Flown in Monday morning, flies out Friday afternoon. That is IJSC schedule. They do whatever it takes to make that schedule, if possible. This would not apply to the 7500 hour, however, but that is usually a once in a lifetime event, if ever.

Other shops may take longer. I typically get it back in less than 2 weeks from my shop. I've never had an inspection last 3 weeks, regardless of scope or squawks.

A proper MU2 shop doesn't let the plane sit like I see many pistons twins do.

Mike C.

It is possible that you can buy and fly. Given the flightaware history, sounds ready to go.

The F model has wimpy -1 engines. They can be temp limited from the ground on warmer days. They don't burn as much fuel, which makes them economical to fly VFR (< 18,000 ft) and for pattern/approach work. It still does 260+ knots, which still leaves every piston twin in the dust.


Yes. The -1 engine. You can eventually get into the low 20s for long range cruise.

I am at the opposite end of the performance spectrum and cost as well.

Mike C.

It looks like he would have pushed it away from the hydraulic puddles before snapping the picture. I don't think the owner thinks a whole lot of the plane when they describe it as a good "time builder". I do agree that it's tempting for the price.

The -1 engine is normally operated on the following schedule:

1800: HSI
3600: HSI, GBI
5400: OH

HSI: hot section inspection
GBI: gear box inspection (technically, TBO extension)
OH: overhaul

Given the hours above, note that OH is not required, but HSI is. So it looks like the first event coming up is left engine HSI in 1070 hours (which has a +/- 100 hour tolerance, so maybe 1170 hours). Then the right engine about 40 hours later, when it will be past TBO technically.


It is almost certain the engines have been traded around a bit on this plane.


Yes, though finding -1 engines with time left is getting harder. It isn't making economic sense to OH a -1 (~$225K?), so people try to find time remaining engines and use them instead. If you could find a 3700 hour engine to swap in for the right when it comes due, that way you have the most hours for the least money. Or you can just HSI the right and keep flying past TBO. In airline service, the TPE331 is doing 9000 hour TBOs, so that wouldn't bother me much.

Mike C.

MU2s have only brakes that use hydraulic fluid.

That is a nice feature as a lot of turboprops have complex hydraulic systems for gear, flaps, etc. and these can get expensive to maintain.


That's MU2 speak for "slow". It also speaks to pilots looking to pile up turboprop time for career reasons and need a cheap plane for that.

Mike C.

I saw that plane, and frankly, if it passed a good pre-buy, it's a very good deal. No, it's not a 300kt Solitaire, but it's a solid 260kt plane in the high teens. It's got good radios, but no radar. For a low 200k airplane, it's a stellar deal and it will give an owner a hell of a plane that still hauls ass compared to most everything else.

Can you swap out different engines in different MU2 models or is each model only certified for one specific engine type?

Unless there is an STC, you have to put in an engine listed on the type certificate. For the F model, that is a TPE331-1 engine.

My plane has an STC upgraded engine. Original was TPE331-6, now I have a TPE331-10AV.

Mike C.

Aerostar will do 265KTAS, so not every piston twin, but yeah, that MU2 is more practical for that speed.

Jet Air in Green Bay gets me in on Monday morning out on Wed. morning, or at least has for my last two inspections. If you've got guys who will work until it's done, it's just a couple of days.