Re: Lightning Strike out of Dorval ?

Date:         16 May 2001 17:45:32 
From:         don@news.daedalus.co.nz (Don Stokes)
Organization: Daedalus Consulting
References:   1 2
View raw article
  or MIME structure

David Simpson  <dsimpson@dsimpson.net> wrote:
>Lightning strikes and static discharges are very spectacular, and certainly
>scary, but highly unlikely to do any real damage. A search of the NTSB (US
>National Transportation Safety Board) database for the last thirty years showed
>not a single accident that could be attributed to a lightning strike or static
>discharge. At worst, one airplane (a small one) had "significant" damage, but
>still landed with no one being hurt.
>(http://www.ntsb.gov/ntsb/query.asp)

The National Ligntening Safety Institute lists a few serious aircraft
accidents relating to lightning at:

    http://www.lightningsafety.com/nlsi_lls/avaition_losses.html

including a lighning initiated wing failure on a 747-131F;

    ...  It appeared that the aircraft had been struck by lightning,
    entering a forward part of the aircraft and exiting from a static
    discharger on the left wingtip. The lightning current's conductive
    path to the static discharger at the tip was through a bond strap
    along the trailing edge. Concentration of current at the riveted
    joint between this bond strap and a wing rib were sufficient
    conductive to cause the flash to reattach to this rivet and to leave
    the discharger. Fuel vapors in the no.1 fuel tank then ignited. The
    explosion caused the upper wing skin panel to separate, causing a
    drastic altering of the aeroelastic properties of the wing, and
    especially the outboard section of wing. The outer wing began to
    oscillate, developing loads which caused the high-frequency antenna
    and outer tip to separate. The whole wing failed a little later.

-- don