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Lightning + Airplane = ?

MIDNJAC

is clara ship
pilot
BigIron said:
We had a lightning strike on the ground. AC power was AFU, and several avionic components needed R&R. Bolt hit the T/R and travelled up to the cockpit. No one fried. Scared the hell out of a maintainer on a B2 stand. Here is a .pdf link with some quasi-technical information about lightning and helos. Not pretty.

http://www.eurocopter.com/site/FO/doc/rotor_j/41/pa-41-22-00.pdf

that reminded me of a story our CO told us. He was involved in the test program for LAMPS at the time of the incident....I can't remember all of the details, but the gist of the story was that they took a lightning strike during a test hop which fried some of their equipment, and sent the a/c into what he described as an uncontrolled descent (although they didn't know why at the time). Apparently the airframe vibrations were bad enough during the drop that neither he or the co-pilot could read any of the instruments. He said that just as he figured that they were done for, they miraculously popped out of the clouds almost directly over Pax River. They managed to put the a/c down, and upon inspection, they saw that the heat of the lightning (from the high voltage) had melted the composite bonds in the rotor blades, so they had each split into several feathered pieces, causing the degredation of control. Pretty wild story I thought:eek:
 

Gatordev

Well-Known Member
pilot
Site Admin
Contributor
BigIron said:
We had a lightning strike on the ground. AC power was AFU, and several avionic components needed R&R. Bolt hit the T/R and travelled up to the cockpit. No one fried. Scared the hell out of a maintainer on a B2 stand. Here is a .pdf link with some quasi-technical information about lightning and helos. Not pretty.

http://www.eurocopter.com/site/FO/doc/rotor_j/41/pa-41-22-00.pdf

Not sure if the -53's engines can even fail to a high-power condition, but if so, did you experience that? That was always my concern if I got hit. Our engines' brains would fry out, causing the engine to overspeed and I wouldn't be able to catch them fast enough. Since I wouldn't have any electrical power, I wouldn't be able to restart them.
 

BigIron

Remotely piloted
pilot
Super Moderator
Contributor
gatordev said:
Not sure if the -53's engines can even fail to a high-power condition, but if so, did you experience that? That was always my concern if I got hit. Our engines' brains would fry out, causing the engine to overspeed and I wouldn't be able to catch them fast enough. Since I wouldn't have any electrical power, I wouldn't be able to restart them.

Our engines' brains are cables and bellcranks. We do not have FADEC, or other computer controlled engines. They are hydraulic start motors which wind the compressor up, and we turn on the spark plugs. Matching 3 engine output is done by a collective bias "block." Old school stuff, but really powerful engines.
However, there are electrical interlocks and logics to start them, so if we had a complete electrical loss, I don't think I could restart them either; although we probably wouldn't lose them in an lightning strike.

I am most concerned with lightning damaging the blades themselves. We ended up sending the blades to NADEP for xray after the hit. Nothing came out of it and I am sure the blades are RFI, if not already in service.
 

webmaster

The Grass is Greener!
pilot
Site Admin
Contributor
@BigIron: [threadjack] Speaking of xrays... what ever happened/resolution, back in the day when we were neighbors and you guys were grounded forever? I just recall you guys coming back finding all sorts of cracks when parts were getting xrayed (or whatever)... Think I was in the FRS when you guys started flying again.... [end threadjack]
 

BigIron

Remotely piloted
pilot
Super Moderator
Contributor
Well I am scratching my head wondering what "downing" period that was. We've had a few. What year approximately was it?
 

webmaster

The Grass is Greener!
pilot
Site Admin
Contributor
BigIron said:
Well I am scratching my head wondering what "downing" period that was. We've had a few. What year approximately was it?
Right after the crash off Corpus and fleet wide grounding, believe it was the squash plate?
 

Gatordev

Well-Known Member
pilot
Site Admin
Contributor
webmaster said:
Right after the crash off Corpus and fleet wide grounding, believe it was the squash plate?

Hang on, let me get my P-3 to helo dictionary out.... Ah, here it is. Squash plate: Swash plate.
 

webmaster

The Grass is Greener!
pilot
Site Admin
Contributor
gatordev said:
Hang on, let me get my P-3 to helo dictionary out.... Ah, here it is. Squash plate: Swash plate.
Whatever, not like I took helo 101.
 

BigIron

Remotely piloted
pilot
Super Moderator
Contributor
Yes it was the swashplate. A critical bearing was seizing in flight and was causing catastrophic failure of the rotor head. They changed all of the fleet rotor heads, changed all of the bad bearings to a new part number, and installed a bearing monitor system. A pretty good fix actually.

I have no idea what "swash" means either. I couldn't use it in a sentence.
 

Schnugg

It's gettin' a bit dramatic 'round here...
None
Super Moderator
Contributor
Damn...building helicopters with pumpkins these days...
 

Wankertank

Free Hat!
copter_side.jpg

Check out those .50 cals on the front...
 
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