greg3322
Posts: 177
Joined: Fri Aug 27, 2004 3:35 pm

Post-Lightning Strike Inspection

Fri Apr 11, 2008 6:12 am

Yesterday, while waiting to board a flight on a UA 767-300 at DEN (UAL1223), we were informed the aircraft has been struck by lightning when it was inbound and had to be inspected prior to it flying again. The aircraft was taken, under power, to the hanger and brought back about an hour later.

My questions:

What type of inspections need to be done to determine the aircraft is safe?

Do modern airlines usually suffer any damage or have problems with a lightning strike?

If I was on the airplane when it happened, would I have known it? Is it loud? Lights go out?

Thanks,

Greg
 
User avatar
Scooter01
Posts: 1183
Joined: Tue Nov 28, 2006 11:06 pm

RE: Post-Lightning Strike Inspection

Fri Apr 11, 2008 7:19 am

Quoting Greg3322 (Thread starter):
Do modern airlines usually suffer any damage or have problems with a lightning strike?

Here is what happened to a Lufthansa 737 after being hit by lightning a few minutes after leaving Sofia, Bulgaria last week:

Left horizontal stabilizer seen from below:
http://i31.tinypic.com/141ukns.jpg

and from above/rear:


Quoting Greg3322 (Thread starter):
If I was on the airplane when it happened, would I have known it? Is it loud? Lights go out?

Newspaper-reports state that some of the passengers saw fire from the left engine, lots of shaking in the airplane, FAs and passengers screaming and crying, but that the Captain kept his cool, managed to turn around and land safely.

Comment from one of the stewardesses to one of the pasengers when de-boarding: "Lucky you!"

(There is a thread about this in the civ.air forum, see "LH Emergency Landing in SOF".)

Hope this answers some of your questions   

Scooter01

[Edited 2008-04-11 00:30:49]
There is always a good reason to watch airplanes
 
Tristarsteve
Posts: 3359
Joined: Tue Nov 22, 2005 11:04 pm

RE: Post-Lightning Strike Inspection

Fri Apr 11, 2008 7:53 am

The inspections are detailed in the MM Chap 5. Sometimes they are very extensive (Fokker100 is one) but usually the initial inspections are not too bad. What takes time is accessing the top of the fuselage and up the tail. You have to find the strike entry and exit points. Sometimes you are lucky and find them quickly, sometimes you never find them because the lightning did not actually strike. I have never seen damage like the LH B737. That is extreme. More noramally you will find a few damaged rivets where the lightning entered, and a missing static wick where it left.It happens to me about twice a year, and in 40 years I have never had damage enough to ground the aircraft. Usually takes about an hour and the damage can go in the MEL for later repair. It is very rare for any systems to be affected, and has happened to me only once.
That was a DeutscheBA F100 that was hit on rotation out of ARN. The lightning caused no structural damage at all but disabled both engine oil pressure sensors! The crew got EICAS messages for Left engine oil pressure, shut down engine, closely followed by Right engine oil pressure, shut down engine. After shutting down the left engine, they decided to ignore the second message and returned. We changed the oil pressure sensors and the aircraft went back into service, but the lightning strike inspection took hours. The TAT Maint office in France said it was a known problem!
 
User avatar
HAWK21M
Posts: 29867
Joined: Fri Jan 05, 2001 10:05 pm

RE: Post-Lightning Strike Inspection

Fri Apr 11, 2008 8:42 am

The Pics show very severe damage which is rare.
Most Lightening stikes would go unnoticed to the Pax.
The Crew normally view a flash of light or a momentary Electrical fluctuation depending on the severity of the strike.
When reported,the AMM advises the Mx staff on the steps to be followed & items to be inspected before clearing the Aircraft back to service.

Observing the Static dischargers for Burns is one good indication.

The Exit point is normally a narrow area.

regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
User avatar
Starlionblue
Posts: 17055
Joined: Fri Feb 27, 2004 9:54 pm

RE: Post-Lightning Strike Inspection

Fri Apr 11, 2008 9:31 am



Quoting TristarSteve (Reply 2):
The lightning caused no structural damage at all but disabled both engine oil pressure sensors! The crew got EICAS messages for Left engine oil pressure, shut down engine, closely followed by Right engine oil pressure, shut down engine. After shutting down the left engine, they decided to ignore the second message and returned.

Yet another argument to keep the fleshbags in the cockpit instead of going fully automated.  duck 
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
CosmicCruiser
Posts: 2049
Joined: Tue Feb 22, 2005 3:01 am

RE: Post-Lightning Strike Inspection

Fri Apr 11, 2008 2:01 pm



Quoting Scooter01 (Reply 1):
Newspaper-reports state that some of the passengers saw fire from the left engine, lots of shaking in the airplane, FAs and passengers screaming and crying, but that the Captain kept his cool, managed to turn around and land safely.

Comment from one of the stewardesses to one of the pasengers when de-boarding: "Lucky you!"

That sounds like a something from a newspaper and the actions and comment from the FAs was uncalled for.

I had a similiar strike in a DC-10 several years ago and it wasn't as dramatic as that. We were in the clouds climbing with light to mod rain. There was certainly the brightest lighting flash I had ever seen and we DID hear it. When we all got our vision back we looked for any warning lights and found nothing abnormal. We continued to dest and made a write up of the probably lighting strike. Maint did the inspection and found 9 burnt spots around R1 and the left elevator, inboard I believe, was missing a chunk of the trailing edge the size of your hand. Had I not seen the burns and missing piece I would have never known it.
 
greg3322
Posts: 177
Joined: Fri Aug 27, 2004 3:35 pm

RE: Post-Lightning Strike Inspection

Fri Apr 11, 2008 2:47 pm

Thank you all for the replies.

Greg
 
EMBQA
Posts: 7795
Joined: Sat Oct 25, 2003 3:52 am

RE: Post-Lightning Strike Inspection

Fri Apr 11, 2008 4:41 pm

Back on-line within an hour..? I find that hard to believe. Most lightening strike inspections I've done have taken a few hours. Lots of stuff to check and look at. Any chance they swapped the plane out...??
"It's not the size of the dog in the fight, but the size of the fight in the dog"
 
greg3322
Posts: 177
Joined: Fri Aug 27, 2004 3:35 pm

RE: Post-Lightning Strike Inspection

Fri Apr 11, 2008 9:14 pm



Quoting EMBQA (Reply 7):
Back on-line within an hour..? I find that hard to believe. Most lightening strike inspections I've done have taken a few hours. Lots of stuff to check and look at. Any chance they swapped the plane out...??

It is possible, although the gate agent stated they will take it away and bring it back after the inspection. I'll have to look at my photos and see if it was the same plane. Does United even keep a spare 767-300 at Denver?

Just looked... It was N674UA when it left, but I didn't get a decent shot when it came back, so I can't prove it. It was an hour and 21 minutes exactly from when the left the gate until they came back.

Greg
 
fr8mech
Posts: 6595
Joined: Mon Sep 26, 2005 9:00 am

RE: Post-Lightning Strike Inspection

Fri Apr 11, 2008 9:54 pm

The lightning strike inspections in the various AMM's I've dealt with all call for a detailed visual inspection of the entire aircraft exterior with emphasis on the trailing edges of the wings, control surfaces and engine nacelles. I've seen plenty of damage that has grounded aircraft for days.

Sometimes you get away with a few pecker tracks along the fuselage. Other times you have numerous fasteners damaged and/or substantial damage to flight controls or large honeycomb structures (thrust reversers, flaps, etc.) I recall one aircraft (a B767) that had 98 separate strike points along the crown of the aircraft. Nasty.
When seconds count...the police are minutes away.
 
SFOMB67
Posts: 371
Joined: Thu Dec 08, 2005 1:20 pm

RE: Post-Lightning Strike Inspection

Sat Apr 12, 2008 3:51 am

During C-Cks it's very common to find lightning strikes on the upper surface of the fuselage. Sometimes you can get away with burnishing it out, sometimes you have to drill small hole to remove the damage and then plug the hole with a rivet. Occasionally you even have to install a repair if the damage is significant. what gets tricky is accessing the repair from inside the cabin. Often times it might be above a galley or lav, which are modules. If I remember right, a rivet had to be a solid fastener, blind fasteners were only temporary and eventually had to be replaced.
Not as easy as originally perceived
 
tdscanuck
Posts: 8572
Joined: Wed Jan 11, 2006 7:25 am

RE: Post-Lightning Strike Inspection

Sat Apr 12, 2008 5:13 am



Quoting Sfomb67 (Reply 10):
If I remember right, a rivet had to be a solid fastener, blind fasteners were only temporary and eventually had to be replaced.

Yep...you get some interval (3500 hours pops into my head, but don't quote me) for the blind fastener, at which point you have to change it out for a solid.

Tom.

Who is online

Users browsing this forum: Bing [Bot], n1786b and 19 guests