turbo piston twin

[Foobar]

A turbo piston twin has broken turbo chargers. Both engines develop full power (40 inches MP) on takeoff at sea level. At about 6000 feet one engine stops at about 32 or 33 inches. The other engine tops out at about 36 inches. Both engines should maintain 40 inches above 10K feet. I say the airplane is not safe or airworthy. Am I wrong?

 

[avbug]

You don't state what "broken" means, but you are correct. If the aircraft doesn't meet it's type certification standards, then it is not airworthy.

Remember that two conditions must exist for an aircraft to meet the requirements of airworthiness. It must be in a condition for safe flight, and it must meet it's type certification and all applicable approved data.

If the aircraft is required to maintain a boost value to a certain altitude, and cannot do it, then it is not airworthy.

Most certainly a host of issues could be at hand, from induction leaks to a faulty cylinder, to a malfunctioning wastegate or controller, to many other possibilities. Many of them are serious.

The airplane shouldn't be flown until they're addressed.

For whatever it's worth, I've flown lots of aircraft that could push 40 inches of boost or more, and I can count the number of times I've pushed them up there on one hand. I like to keep that MP low...so long as my butt is tattoed to that airplane and married to that engine, I'll treat it like a part of my own body (no, not that one...the one I don't abuse)...

 

[Foobar]

Agreed, I noticed because at 5000 feet one throttle was near the stop so just to check I pushed them each up to the stop to see what I'd get. Aside from takeoff I never run those engines to 40 inches. Usually I back off to about 32 inches in climbout per the manual.

I say broken because I'm not an A&P and all I know is they don;t work the way the manual says they are supposed to.

 

[Kingairrick]

Two big causes of turbo failure are:
1) Exhaust problems- 1500 degrees!
2) Lubrication issues- OIL!

Still want to fly it?

 

[SabreFlyR]

Several possibilities on this one. Could be exhaust leak(s), waste gates frozen/out of adjustment, turbo controllers out of adjustment or worn out, tubo's worn or damaged.
Likely hood that it's a bad engine is rare. In most cases you can have a cylinder with little to no compression and you would not even notice it, unless it's split a head or something severe like that.

My real concern here would be the type of plane.
Twin Cessna's and exhaust leaks can be deadly. Piper twins, annoying but the wing isn't going to burn off.