According to the flight instructor and pilot receiving instruction, they conducted a preflight inspection of the Diamond DA-40NG, with no anomalies noted, before departing from Runway 21 at Johnston Regional Airport (KJNX) in Smithfield, North Carolina.
Review of radar data revealed that the airplane climbed to an altitude of about 650 feet while turning left.
The flight instructor stated that she “heard a weird noise come from the engine” and saw the rpm gauge drop.
Shortly afterward, she directed the pilot receiving instruction to turn back to the airport, and the engine lost total power while in the turn.
The flight instructor attempted to restart the engine while the airplane descended but was unsuccessful.
The airplane subsequently hit trees about a mile from the departure end of the runway, resulting in substantial damage to the fuselage. In addition, both wings and the empennage were fractured from the impact.
Both the flight instructor and pilot receiving instruction were seriously injured.
A post-accident examination of the engine revealed that engine valve train was not timed correctly and that the resulting misalignment resulted in the piston striking the valve. The valve head had subsequently separated and fallen into the cylinder.
Examination of the maintenance logbooks revealed that the cylinder head and exhaust camshaft had been replaced the day before the accident.
Probable Cause: Maintenance personnel’s failure to set the correct engine timing after the replacement of a cylinder head and exhaust camshaft before the accident flight, which resulted in a total loss of engine power.
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This March 2022 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
Is our not an obvious rule if thumb to initiate a return immediately upon detecting an anomaly?
I just hate that the report had to include that “shortly thereafter” phrase.
Hope they made (or will make) a full recovery.
My sim work on the “impossible” turn has shown me climbing at Vx and doing a short field takeoff keeps my 172 higher and closer to the Runway in case of low altitude engine out. With 486 feet to work with she would have been a lot closer to the airport. Losing 486 feet and still being a mile away after a turn back is hard for me to grasp.
Comparing sym results for the same model airplane wouldn’t be realistic. Comparing sym results for an entirely different model airplane is really irrelevant.
It is not irrelevant to grasp the principal of climbing fast while close to the runway so you have a better chance of being in a clear area should you need to return. The DA40 travels 1935 feet to get to 50′; to go another 436′ with a Vy climb rate of 650 fpm takes them another 40 sec. or a little over 2/3 of a mile (~3600′). Since KJNX Rwy 21 is 5500′ the aircraft could have been at the departure end when they decided to turn back. Impacting more than a mile away from the departure end after making part of the turn at power tells me that they likely did not make climbing out expeditiously a priority. Simulators reinforce principals and yes, the details change for every aircraft but making a priority to gain altitude while near the runway seems like a good thing to prioritize and make a standard practice. Using a Sim so you know how your plane will respond is great at reinforcing these principals.
I read the majority of the info, and the engine logbooks provided in the NTSB report.
JimH’s “free spinning” engine is a NON Interference engine. This Diesel appears to be an interfernce engine. So if the valves are not timed correctly they will contact their piston.
I find it hard to believe that this engine in this report had a mistimed exhaust valve. In checking the engine, one would have to turn the engine by “hand” (long handled socket wrench) to verify work. You would feel the connection and you would not be able to turn past it without damage, if you had the strength to do it — Impact wrench is the wrong thing to use for this test.
As a result, starting that engine as a test should have revealed some problems immediately. Having it on the line, starting it up, doing the taxi to the runup area and then the full runup and no anonmalies detected? If that piston and valve where coliding I don’t see how, at full power, they could make it to Vr without knowing something was really not right.
I think something else went wrong causing that valve to get out of time, or just fall and get hit and bend the stem and…..
Just my 2 cents.
It’s interesting that the AD to replace the fuel injectors also required replacing the timing chain due to excessive wear….which was not noted in the engine log entry. ?
So, was it not replaced since the engine was at 895.8 vs the mandatory 900 hrs ?
A worn timing chain could cause the exhaust cam to be out of time…if the cam was retarded, the exhaust valves would close later on the exhaust stroke and contact the pistons.
From the pic of the cylinder head , only one of the 8 exhaust valves failed, with no apparent damage to any of the others.! Very strange.!
We used to do a test flight after each repair which included re-adjustment of engine or flight controls.
Also, as a CFI (PIC !!!) on that flight I would have taken over controls in a critical situation instead of ”directing the pilot receiving instruction“.
First fly the airplane!!!
(directed the pilot receiving instruction, CFI, A&P)
Is it just me, or does it sound like from the beginning, they are more worried about the cost and money they’ve lost in this plane. Instead of the pilots life’s or injuries.?
There was a lot of engine parts [ expensive !], replaced in the 800+ hours on this engine.!!
So, a stripped screw required replacing the cylinder head, and the A&P installed the exhaust camshaft mis-timed…!! t
There are usually timing marks on the cam gears and the crankshaft to aid in getting the timing correct.
I’m surprised that the engine didn’t run poorly with the mis-timed exhaust valves.?
All of the work on this engine makes me concerned about the reliability of this auto conversion.
An added thought;
The Continental engine in my Cessna 175 is a ‘free spinning engine’, meaning that a stuck exhaust valve cannot hit the piston.
I had an exhaust valve stuck wide open and there was no damage, [ damn lead !].
I had to ream the guide to remove the lead deposits and the engine is ok-fine now.!!
The title should be ‘…mechanic fails to set the exhaust camshaft timing correctly’.
Just wondering if you bore scoped the rest of the cylinders! And did you find lead deposits on the others also? A&P Mitch
Mitch,
I removed all the valve covers , removed the valve springs and checked the valve movement. [ the rope trick].
#3 was stuck open, #1 and 5 would stick part way open, so I reamed all 3.
#2,4 and 6 were ok…strange.?
The oil cooler is in front of #1,3 and 5, so those cylinders run a bit hotter.
A borescope would not detect deposits on the valve stems. I did scope them and all 6 looks ok.
The engine now has 100 hours since the reaming and is running great.
I’ll be checking #3 at 350 hours per the Lycoming SB 388C, or if it missfires on cold start.!!
I suspect that since we now use a qt of oil in 10+ hours, the lead in the oil has greatly increased from about 1,800 ppm to over 3,000 ppm. So, now I’m changing oil at 30 hrs vs 50 hrs. If the oil analysis still shows high lead, I’ll reduce oil changes to 25 hrs. and see….
I can’t wait for unleaded 100..!!!
The Diamond DA-40NG aircraft had an Austro E4-A Diesel (Jet-A) Engine.
https://www.diamondaircraft.com/en/austro-engine/e4-series/overview/