TBO questions to bring up during the search for my next Turbo Commander

[Adam Frisch]

All the Commander have pretty low turbulence penetration speeds, after it was lowered. I would still prefer the 840 over a 690 because of the newer wing spar without inspection and corrosion possibilities. No need to worry, they're stout wings.

[donv]

The low utilization thing isn't really necessary in the Commander. The Citation has all sorts of calendar items which can be pretty costly if you aren't flying much. The Commander really just has the annual inspection and 5 year gear and prop overhauls.

In regard to accident/incidents in Commanders, let's start with the gear. Typically, you see those gear collapse accidents when either the gear overhauls were not done (or, more likely, were just done on paper) OR they were not done correctly. There were a rash of them in the early 2000s that involved incorrectly done gear overhauls-- I don't remember exactly what the issue was. If the gear is properly maintained by someone who knows what they are doing, it is very stout and should not be an issue.

Turbulence: all of the Turbo Commanders from at least the 690 on, maybe before (not sure), have a placard on the panel which says not to exceed 180 knots in moderate or greater turbulence. The limitation is the same for the 690 and the Jetprops (840/980), and I don't think there are any issues which are worse than one versus the other. In fact, the wing was completely redesigned internally for the Jetprops, so I would be more comfortable in one versus a 690, although I'm fine in either.

If you fly into a thunderstorm, it really doesn't matter what you are flying. TBMs, Pilatuses (Pilati?), King Airs, they have all broken up in thunderstorms, as have Commanders. I wouldn't worry about it more in a Commander than in any other airplane, and I do my best to stay away from thunderstorms, especially when I see lightning strikes on the G600.

What is a problem in Commanders, and you might have picked this up, is stall/spin accidents, whether in training or in normal operations. It appears to me, some disagree, that if you end up in a spin in a Commander, it won't be recoverable. So don't go there.

[Dan Freedman]

Thanks donv, for your comments on LUMP. I spoke to someone at National Flight Services who was mentioning something about a "12 year" inspection, but I haven't heard that elsewhere. Anyway, I don't think I'd use LUMP to move 12 years to 24 -- that's a bridge too far. But I am a believer in the concept that many failures are induced by the maintenance intended to protect against failure. I'm not in any way ant-maintenance. But I had a friend with a TBM who, after last year's insection of the wing to ensure no internal fuel leaks (of which there were none), ended up with a puddle of Jet-A on his hangar floor. MIF.

And after what I read about the gear, I'd be inclined to be generous on gear inspections.

And, JMA, who knows, in a couple years, perhaps I'll be ready for a 980.

In trying to put a proper valuation on engines, I'm struck by the beauty of the TPE331's 5000 hour TBO, yet also the dilemma for a Part 91 operator, who knows the engine can be maintained without overhaul, and for whom the price of a pair of overhauls is equivalent to the price of the hull. But to a 135 operator, all those hours have value that is elusive for a private owner to make use of.

Anyway, the search continues.

[Bruce Byerly]

12 year was a one time inspection

[donv]

Bruce, was that a gearbox inspection?

[Bruce Byerly]

Bruce, was that a gearbox inspection?

No the airframe had a 12 and 15 year inspection. Those days are past.  Many were just done twice or even 3x but not proven to be needed.