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Lightning strike

Posted: Mon Sep 12, 2016 8:54 am
by ememic99
I usually don't post same stuff accross multiple forums but I find that this could be good reading for Diamond community.

On flight from Avignon to Ljubljana on August 31st I got lightning strike during descent towards Ljubljana airport.

We took off at 12:15 UTC from LFMV and majority of the flight was in VMC above cloud tops except part of departure. I noted storm-cell developing activities both north and south from our route using on board stormscope and ADL120. During descent through TCU clouds towards Ljubljana airport, electrical discharge hit the aircraft. Stormscope showed full screen of electrical activity and then continued to throw lightning failed error.

I disengaged autopilot, checked aircraft controls, lowered airspeed, continued descent and started to asses other possible damage. Both engines were functioning correctly, responding to increased and decreased throttle. Airspeed indicators and engine indicators were consistent as well as both attitude indicators and both altimeters. I checked landing gear (down and up) and checked flaps (lowered them to approach position and up), noting correct functioning.
I noticed black spot on left winglet assuming this to be discharge exit point. We left IMC before reaching assigned altitude and I reported incident to ATC and asked to divert to Lesce (LJBL – Diamond service is located there) for full check required after lightning strike. I also noticed smaller black spot on right winglet as well. At that moment we were at approximately same distance from LJLJ and LJBL in full VMC conditions so I decided that’s more practical to land at LJBL.

Divert was approved as well as visual descend to 1000 feet AGL, no help in navigation was needed since we were visual and majority of avionics was working correctly. I crosschecked aircraft’s GPS with the one on iPad, checked both radio stations and both NAV receivers, DME and ADF and everything seemed to function correctly. Further check showed that main tanks fuel indicators didn’t work but according to flight log (64.7 USG at takeoff and average 11 USG/h within 3 hours of flight) and fuel totalizer, we were ok with fuel assuming no leaks. However, I reported this to ATC as well.
At that moment I had LJLJ airfield in sight and after arriving traffic I was allowed to descent further to W2 and W1 points towards LJBL airfield. When reaching W2 I got permission to leave the frequency and to switch to Lesce and I asked for flight plan to remain open until I confirm successful landing with phone call from ground.

Runway in used at LJBL was 14; I reported W1 and later on final runway 14, got permission for landing and successfully landed aircraft at 15:35 UTC.

Re: Lightning strike

Posted: Mon Sep 12, 2016 2:16 pm
by ihfanjv
Wow!

First, thank you for posting. Second, that looks like substantial damage. I would imagine that there is similar damage within the airframe at attachment points between composite parts - wing to fuselage and rudder to fuselage, for example.

What part is the first picture?

Is there a possibility that the aircraft is damaged beyond repair?

Re: Lightning strike

Posted: Mon Sep 12, 2016 3:03 pm
by ememic99
Left winglet is at the 1st picture. Up to now no additional damage was found - both winglets, stormscope, fuel indicators.

Re: Lightning strike

Posted: Mon Sep 12, 2016 6:05 pm
by Thomas
Hi Emir
It seems that your plane is in good hands with Matjaž of AeroService Lesce. I met him in August and thinking of bringing my DA40 to them for some necessary work.
I Would be interested in your opinion about the quality of the company.

Re: Lightning strike

Posted: Mon Sep 12, 2016 6:48 pm
by ememic99
Matjaž runs very good facility, he's very experienced mechanic and pilot. He's been maintaining my DA42 for more than 2 years (since I own it).

Re: Lightning strike

Posted: Tue Sep 13, 2016 9:23 pm
by CFIDave
Since we're discussing recent lightning strikes, here's what happened to my friend's DA40 after his 3-blade MT prop got struck while the plane was parked -- tied down at Freeway airport (W00) in Maryland (you can see the blade's wood core):
Image

Since the lightning passed through the Lycoming engine, as a precaution he had a complete engine tear-down performed to check for damage (and while doing that opted for a full engine overhaul -- paying for the difference above insurance reimbursement). And as you might expect he also got a prop overhaul and a new set of MT prop blades.

What you might NOT have expected is that the plane got magnetized by the lightning strike. Using a magnetic flux meter (available as an iPhone app) he determined the the strike must have exited the plane via the left main landing gear steel leg. The G1000's magnetometer located out on the wing would no longer provide a correct compass reading. Despite being a composite airframe, much of the plane had to be de-gaussed to remove the residual magnetism. One of the wings had to be pulled to fix an inoperative fuel gauge, and resistance measurements had to be made to check for correct operation of the plane's grounding/electrical bonding system.

The good news is that after only about 2 months for repairs everything works perfectly and the plane is flying again! :)

Re: Lightning strike

Posted: Tue Sep 13, 2016 10:40 pm
by ihfanjv
CFIDave wrote:Since we're discussing recent lightning strikes, here's what happened to my friend's DA40 after his 3-blade MT prop got struck while the plane was parked -- tied down at Freeway airport (W00) in Maryland (you can see the blade's wood core):
Image

Since the lightning passed through the Lycoming engine, as a precaution he had a complete engine tear-down performed to check for damage (and while doing that opted for a full engine overhaul -- paying for the difference above insurance reimbursement). And as you might expect he also got a prop overhaul and a new set of MT prop blades.

What you might NOT have expected is that the plane got magnetized by the lightning strike. Using a magnetic flux meter (available as an iPhone app) he determined the the strike must have exited the plane via the left main landing gear steel leg. The G1000's magnetometer located out on the wing would no longer provide a correct compass reading. Despite being a composite airframe, much of the plane had to be de-gaussed to remove the residual magnetism. One of the wings had to be pulled to fix an inoperative fuel gauge, and resistance measurements had to be made to check for correct operation of the plane's grounding/electrical bonding system.

The good news is that after only about 2 months for repairs everything works perfectly and the plane is flying again! :)
Remarkable story!

Thanks for posting!