DA40NG loss of turbo charger boost

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Boatguy
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DA40NG loss of turbo charger boost

Post by Boatguy »

This only applies to the DA40NG and not the DA42 or DA62 Austro powered Diamonds as their engines have different turbocharger plumbing. The NTSB released their report (attached) on the partial loss of power that led to an off field landing last summer. Nothing in my comments, and hopefully nothing in this thread, is intended to second guess the pilot's actions which resulted in a safe off field landing.

The summary of the accident is that after a touch and go at 300AGL the hose connecting a fiberglass air duct to the intake manifold came disconnected resulting in the loss of boost air pressure. As you can see in the attached photos, the hose had three hose clamps which were safety wired. With the power lever at 100% the engine delivered about 44% power. I am aware of a similar accident where the hose from the intercooler to the fiberglass duct became disconnected, but in that case the clamps were not safety wired. Neither accident resulted in injuries and both occurred less than 20hrs after being serviced.

I made two conclusions after reading this report.

1) To service the gear box oil, the hose from the intercooler to the fiberglass duct, and from the fiberglass duct to the intake manifold must be removed and refitted every 100hrs and at the annual. These two accidents suggest that I should physically inspect and confirm the attachment of the two turbocharger hoses after servicing. The hose connections carry air under pressure and should certainly not yield to a healthy pull when on the ground.

2) The AFM performance tables say the plane will hold altitude at 45% power. However, it is silent on the procedure to follow with a partial power loss, though it seems obvious that "land at nearest" would be the proper course of action! Besides hoses coming loose, there are other ways to loose boost pressure. I intend to ask Diamond to update the AFM with a procedure for turbo boost loss. In the interim I am planning to do some testing at a safe altitude to determine how my plane operates at reduced power. I already know I can fly a 90KIAS holding pattern at 40% power, but I've not tried to climb at 40%, tested the performance at 40% with TO flaps, or tested the performance at 30% power clean.
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Colin
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Re: DA40NG loss of turbo charger boost

Post by Colin »

A fellow in the hangar across from my tie down at KSMO had a C182. He flew back and forth to the Bay area since he was a doctor. After one of his annuals the intake manifold hose came loose, resulting in total power loss. He was almost to Van Nuys when it happened and he just landed on the I-405 north. They blocked traffic for him to take off again after he had popped the cowling, found the clamp undone, and repaired with a screwdriver.
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Mdm0515
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Re: DA40NG loss of turbo charger boost

Post by Mdm0515 »

Boatguy wrote: Tue Jun 23, 2020 12:44 am This only applies to the DA40NG and not the DA42 or DA62 Austro powered Diamonds as their engines have different turbocharger plumbing. The NTSB released their report (attached) on the partial loss of power that led to an off field landing last summer. Nothing in my comments, and hopefully nothing in this thread, is intended to second guess the pilot's actions which resulted in a safe off field landing.

The summary of the accident is that after a touch and go at 300AGL the hose connecting a fiberglass air duct to the intake manifold came disconnected resulting in the loss of boost air pressure. As you can see in the attached photos, the hose had three hose clamps which were safety wired. With the power lever at 100% the engine delivered about 44% power. I am aware of a similar accident where the hose from the intercooler to the fiberglass duct became disconnected, but in that case the clamps were not safety wired. Neither accident resulted in injuries and both occurred less than 20hrs after being serviced.

I made two conclusions after reading this report.

1) To service the gear box oil, the hose from the intercooler to the fiberglass duct, and from the fiberglass duct to the intake manifold must be removed and refitted every 100hrs and at the annual. These two accidents suggest that I should physically inspect and confirm the attachment of the two turbocharger hoses after servicing. The hose connections carry air under pressure and should certainly not yield to a healthy pull when on the ground.

2) The AFM performance tables say the plane will hold altitude at 45% power. However, it is silent on the procedure to follow with a partial power loss, though it seems obvious that "land at nearest" would be the proper course of action! Besides hoses coming loose, there are other ways to loose boost pressure. I intend to ask Diamond to update the AFM with a procedure for turbo boost loss. In the interim I am planning to do some testing at a safe altitude to determine how my plane operates at reduced power. I already know I can fly a 90KIAS holding pattern at 40% power, but I've not tried to climb at 40%, tested the performance at 40% with TO flaps, or tested the performance at 30% power clean.

635859.pdf

635857.pdf

292RA.pdf
I was piloting N113NG, a DA40 NG as a rental on 11/17/18. The airplane was essentially brand new at about ~130-140 hrs Hobbs and had undergone its 1st service. At about 4500’ and climbing and 8 miles from departure station there was a loud bang up front, simultaneous pitch down and power loss. Uh oh. Both ELT’s faulted on the PFD. Attempting full power lever input would not yield greater than 40-45% actual power, but I could still fly the airplane and maintain altitude. Made my return to station and landed safely. I was told by owner/operator that a clamp connecting a hose to the manifold (or turbo, I forget) popped off and that the engine software intentionally reduced the power to the 40-45% to allow for a safe landing somewhere. I was later told this became an AD which is to be enforced by A&P’s during servicing, ie ensure clamps are properly and tightly secured.
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Re: DA40NG loss of turbo charger boost

Post by AndrewM »

Well done for you Matt on safely handling the situation. Definitely an "Oh-S*!T" moment...
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Boatguy
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Re: DA40NG loss of turbo charger boost

Post by Boatguy »

Mdm0515 wrote: Thu Jun 25, 2020 3:33 pm I was piloting N113NG, a DA40 NG as a rental on 11/17/18. The airplane was essentially brand new at about ~130-140 hrs Hobbs and had undergone its 1st service. At about 4500’ and climbing and 8 miles from departure station there was a loud bang up front, simultaneous pitch down and power loss. Uh oh. Both ELT’s faulted on the PFD. Attempting full power lever input would not yield greater than 40-45% actual power, but I could still fly the airplane and maintain altitude. Made my return to station and landed safely. I was told by owner/operator that a clamp connecting a hose to the manifold (or turbo, I forget) popped off and that the engine software intentionally reduced the power to the 40-45% to allow for a safe landing somewhere. I was later told this became an AD which is to be enforced by A&P’s during servicing, ie ensure clamps are properly and tightly secured.
I think you mean both EECU's (electronic engine control units), not ELTs?

You got some questionable information.

- The engine doesn't intentionally reduce the power, that's just all the power it can make without a turbo-charger.

- I'm not aware of an AD or SB for the hoses, though I think an SB would be a good idea.

Very glad to hear you could hold altitude and fly the plane back to the aiport with 40-45% power. Well done!
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