NTSB Says Mike Patey ‘Knowingly’ Installed Unserviceable Engine

Lindberg said:
Not to mention this: "[T]he engine was found
to be in poor overall condition with missing surface protective paint and surface corrosion
noted throughout the external and internal surfaces of the engine."

Building an unairworthy plane that you plan to fly yourself is incredibly stupid. Building one to donate that someone else might fly is criminally reckless.
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This is paper bag territory.

Much has been made of the poor condition of the external paint and the corrosion. But what is expected of a 1987 manufacture PT6 that has almost 3,600 hours since overhaul? Is the paint in poor condition on other engines of this age and time? Is some corrosion normal? Is the corrosion found on and in this engine abnormal?

The ITT is normally around 1,600° F. Can that cause the identified corrosion after 3,600 hours?

The RGB likely failed due to engine torque loads. The docket notes the torque control was shipped with the engine to P&W, but it was not tested. Why not?

Does "unserviceable" mean the engine had unresolvable flaws, or is it because P&W found it beyond economical overhaul?

There is a lot of pontificating going on, but I haven't read any comments from anyone that is actually familiar with the issues I have mentioned. Perhaps those that own or fly airplanes powered by the typical Lycoming or Continental are a bit out over their skis with their comments.
 
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never heard of this dude. Maybe he should get a better engine though and try not getting investigated by the NTSB

in other news, here's a vetted guy I was sitting next table over to in the GSR steakhouse in Reno on Thursday night (we may have both been there for the same purpose/convention that Dos Gringos was also there for the next night)
 
3393RP said:
Much has been made of the poor condition of the external paint and the corrosion. But what is expected of a 1987 manufacture PT6 that has almost 3,600 hours since overhaul?
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A lot more than that. The 3600hr limit is the standard OH limit. Most in-use engines are on some sort of OH extension program which can give you up to 8000hrs between OHs. There are PT6s out there with over 20,000TT on them and some probably even higher. When properly taken care of, they are as close to bullet-proof as you get for an engine. And as I mentioned earlier, the fact this engine has 9400 TT and is still on a standard OH limit along with its physical condition further leads me to believe it was part of Leasco’s rental fleet and most probably had lost records given some of the statements in the docket report.

3393RP said:
Is the corrosion found on and in this engine abnormal?
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For an operational engine, yes and especially on the internal areas. It is a sign the engine has sat for an extended time and was not properly maintained. While that condition is not a regulatory concern for an E/AB, from a performance perspective it should have a concern of the buyer especially since the compressor blades cleaned the shroud corrosion during its run.

The fact he simply changed the oil and filters and did some misc tasks prior to flying shows either a high level of ignorance or a case of intent to just get there. And the last time I checked, turbine E/ABs needed some sort of acceptable inspection program as part of the Ops Limits which should have required more work on that replacement engine. Well, at least on the turbine E/AB helicopters I worked on they required an inspection program.

3393RP said:
The ITT is normally around 1,600° F. Can that cause the identified corrosion after 3,600 hours?
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No. Lack of proper maintenance provides a path to the corrosion.

3393RP said:
The RGB likely failed due to engine torque loads. The docket notes the torque control was shipped with the engine to P&W, but it was not tested. Why not?
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My guess, the goal of the NTSB is to determine probable cause which was the engine failed due to internal failure. But since the engine was sold as unserviceable the requirement to further test (vs the failure of a serviceable engine) was not required as it would not change the Probable Cause.

3393RP said:
Does "unserviceable" mean the engine had unresolvable flaws, or is it because P&W found it beyond economical overhaul?
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Doesn’t matter. It’s a method vendors will use to declare the items condition to the public. No different than venders label items “experimental” even though there is no regulatory classification for experimental parts. Its more a general CYA and puts the responsibility on the buyer. Have bought many items and parts with “unserviceable” or similar on the paperwork.
 
I cannot find a reference for it at the moment but IIRC he had purchased this engine some years (7 years?) ago for another project. He had a video of putting it into a lighted case during the Draco build.

He mentioned his business partner hot started the old engine in this airplane, which forced him for an unscheduled install of this one in order to get the plane to Osh.
 
Bacho said:
I cannot find a reference for it at the moment but IIRC he had purchased this engine some years (7 years?) ago for another project. He had a video of putting it into a lighted case during the Draco build.

He mentioned his business partner hot started the old engine in this airplane, which forced him for an unscheduled install of this one in order to get the plane to Osh.
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For static display, I think a truck would have been a better and cheaper option…
 
Bell206 said:
A lot more than that. The 3600hr limit is the standard OH limit. Most in-use engines are on some sort of OH extension program which can give you up to 8000hrs between OHs. There are PT6s out there with over 20,000TT on them and some probably even higher. When properly taken care of, they are as close to bullet-proof as you get for an engine. And as I mentioned earlier, the fact this engine has 9400 TT and is still on a standard OH limit along with its physical condition further leads me to believe it was part of Leasco’s rental fleet and most probably had lost records given some of the statements in the docket report.


For an operational engine, yes and especially on the internal areas. It is a sign the engine has sat for an extended time and was not properly maintained. While that condition is not a regulatory concern for an E/AB, from a performance perspective it should have a concern of the buyer especially since the compressor blades cleaned the shroud corrosion during its run.

The fact he simply changed the oil and filters and did some misc tasks prior to flying shows either a high level of ignorance or a case of intent to just get there. And the last time I checked, turbine E/ABs needed some sort of acceptable inspection program as part of the Ops Limits which should have required more work on that replacement engine. Well, at least on the turbine E/AB helicopters I worked on they required an inspection program.


No. Lack of proper maintenance provides a path to the corrosion.


My guess, the goal of the NTSB is to determine probable cause which was the engine failed due to internal failure. But since the engine was sold as unserviceable the requirement to further test (vs the failure of a serviceable engine) was not required as it would not change the Probable Cause.


Doesn’t matter. It’s a method vendors will use to declare the items condition to the public. No different than venders label items “experimental” even though there is no regulatory classification for experimental parts. Its more a general CYA and puts the responsibility on the buyer. Have bought many items and parts with “unserviceable” or similar on the paperwork.
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Thanks for taking the time to provide this informative answer.
 
Bell206 said:
There are PT6s out there with over 20,000TT on them and some probably even higher. When properly taken care of, they are as close to bullet-proof as you get for an engine.
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T6-A Texan uses the 1,100 shp PT6A-68 and the AF is experiencing challenges keeping them flying due to parts availability (like the T-38, kinda expected when you're maintaining a fleet well beyond their anticipated service life)- but definitely an attestation to their reliability.
 
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tobnpr said:
but definitely an attestation to their reliability.
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I think even greater proof of that reliability is the core design from those original PT6A models is the same core design used in the new PT6E models decades later.
 
tobnpr said:
T6-A Texan uses the 1,100 shp PT6A-68 and the AF is experiencing challenges keeping them flying due to parts availability (like the T-38, kinda expected when you're maintaining a fleet well beyond their anticipated service life)- but definitely an attestation to their reliability.
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We were looking at putting a very special airframe back into the air, long years ago. Priced the one part we had to have from Pratt to even consider doing it...$15,000 just to tool up for it and somewhere north of $50K for the part itself. Less than 100 of that version of the PT-6 were ever built and there were no parts available that were specific to that engine series. Anything that was common to other series, no problem.
 
wanttaja said:
In any case, there aren't many case of the public being injured when a homebuilt has a mechanical issue. Don't recall any, in my analysis, though it wasn't something I was tracking and may have missed some cases.
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After I posted this, I realized that injuries/fatalities on the ground WERE included in the NTSB accident database. So I ran a quick analysis.

From 2008 through 2023, there were about 3200 accidents involving Experimental Amateur-Built aircraft. Thirteen of these resulted in injuries to people on the ground. Over half (eight) produced only minor injuries to the people on the ground.

Of the remaining five, three cases resulted in fatalities beyond the occupants of the aircraft; a total of four fatalities. These cases were:

LAX08LA274, Velocity lost engine on takeoff and crashed in residential area. Aircraft had five hours total time. Two ground fatalities.
ERA10LA175, Lancair IV lost engine during cruise, force landed on a beach and struck a person. Ninety-nine hours total time. One ground fatality.
WPR16FA091, Lancair IV lost engine during cruise, force landed on a highway and struck a parked car. 350 hours total time. One ground fatality, three other persons on the ground seriously injured.

Two additional accidents resulted in serious injuries among people on the ground, but no fatalities.

ERA12FA265, Seawind lost power on takeoff and crashed into a supermarket. Two minor, one serious injury on the ground. NTSB report doesn't list aircraft total time, but the airplane was more than ten years old.
ERA19FA034, Cavalon gyro with rotor issues during cruise, hit residence, one serious injury on ground. 16 hours total time. The aircraft was newly-purchased by a second owner.

In summary, out of ~3200 EAB accidents, only one was still in its test period when it struck and killed persons on the ground.

Ron Wanttaja
 
P&W sells a lot of "unserviceable" engines. Sometimes they old enough or have a history that makes them not worth overhauling for P&W's Leaseco unit so P&W doesn't waste any effort inspecting the engine itself. Other times they are truly clapped out. All of them are simply sold as "unserviceable". Many go on to run for hundreds or thousands of hours with no issue.

I'm sure Mike talked about the engine like he did because he was aware of the SB (or his people were) and given how the engine failed you'd immediately suspect you had bad gears but the SB hadn't been completed.

I find it unfortunate the NTSB saw "unserviceable" and closed the book. I would like to have an analysis of the gears that failed since there is an outstanding SB on certain gears for failing in this exact manner. It appears his engine did not have gears covered under that SB but should they have been covered? Or should gears of similar SNs be put on a limited-lifetime list? Even engines destined for the scrap pile don't usually have bad gears. The things that fail are the fans, bearings, etc. If I were Mike I'd send the gears to a lab for analysis. Why did they fail? A defect in the original casting? Crack?

As others have noted none of the "poor condition" issues relate to the gear reduction system. Shame on Mike for not doing a thorough inspection on the engine's condition, that's on him. But its entirely possible even a full hot section inspection wouldn't have found anything wrong with the gears.
 
xenadu said:
It appears his engine did not have gears covered under that SB but should they have been covered?
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I wouldn't think so. As I recall the gears in question were the Timken PMA gears and this engine had Pratt gears. Regardless, my guess is that sun gear failure was secondary to the PT shaft failure and subsequent overspeed given the 1st stage planet gears could still be rotated and their shafts/bushing were not damaged.
 
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