lightning strike on an airliner
 

I was inbound to LHR from TXL on Friday on BA 985 when, just as I was pointing out the Millenium Dome to my travelling companion, I saw (and instantaneously heard)a fork of lightning hit the left wing tip of the 757. I was surprised at how loud the bang was inside the cabin and, judging by the reaction of my fellow passengers, most of whom would not have seen the event, it unerved a good many of them.

There was no explanation from the flight crew untill we were pulling onto the stand. The Captain anounced that a lightning bolt had hit the aircraft just beside his left knee.

Are lightning strikes a regular occurence?

As an aircraft is not earthed, do they just pass through the aeroplane as though it were not there, or can it cause damage?

Should flight crew not inform the passengers immediately as the bang was obvious to everyone?

Presumably if you were passing the Dome you were on the approach, therefore the flightcrew and cabin crew were busy with the job in hand, ie getting the aircraft on the ground. Lightning strikes happen fairly frequently and USUALLY pass with no problem through the airframe. The phrase that describes the flightcrew's prioritisation best is Aviate, Navigate then Communicate.

wizzy

Lightening can cause a surprising about of damage and sometimes the loss of the aeroplane (IIAF B707 over MAD many years ago comes to mind). I personally have had only two in 35 years of flying, both with propellor driven aircraft, FH227 & DC-6. In the case of the DC-6, two inches of one of the blades of #4 prop went missing...not good!

Here is a link to the Tech Log archive thread regarding lightning strikes:

Lightning Strikes

Checkboard has some good tech info and additional links in his posting on that thread, and Pterodactyl explains the Faraday Cage principle (which is what protects passengers from the effects of the lightning).

i was on a qantas 747-400 about 7-years ago
about 12 minutes out of christchurch en-route
to sydney when we were bolted by lightning,
later on in the flight i visited the cockpit
and asked the boss about it, he said it had
hit just outside the cockpit right where his
left knee would be, on arrival in sydney
i had a good look at the exterior around the
cockpit, but there was no visible sign on being hit.

(edited to correct watt 12-years of schooling
could not)

[ 04 September 2001: Message edited by: ZK-NSJ ]

Have been struck by lightning on two occasions. Both cases were just west of LHR giving a big bang but no damage. The engineers did though have to re-protect some of the rivets near the site of the strike. The strike removes the protective coating (e.g. paint!) on the heads of rivets and so this has to be reapplied.

One of these strikes was on a training trip and the poor lass doing her first 757 take-off did extremely well in maintaining her lady-like decorum!

Strikes can have differing effects. On most occasions the electrical path of the lightning just runs around the outside of the fuselage and then discharges to ground with no effect to the aircraft. For the technically minded it acts as a "Faraday's Cage". But there have been reports of ball lightning travelling down the aisles, a door being welded closed and there is the case of the BA 757 FO whom caught a stray bolt on the approach to AMS. He survived, but I believe has some medical probs with cardiac rhythm distortion caused by the strike.

Be careful out there.........