Lightning

[Robert Atkinson 2Participant @robertatkinson2]

And this accident involving a Do228 commuter aircraft.
http://www.aibn.no/Aviation/Reports/2007-23-eng

The thread on the rose joint end of the elevator control rod (part of a turnbuckle like adjustment) was blown out by the lightning current. The design had a bonding lead across the joint but this had not bee maintained properly.

The report gives a bit of background on the currents involved.  As I’ve said before lightning protection of aircraft and avionics is one of my professional areas of expertise. Probably the hardest protection is fuel tanks when 200,000 amps is flowing through the skin without causing sparks of more than 200 microjoules inside. This includes rivets, pipe joints etc.

Full direct effects testing is always interesting. Pin injection testing for secondary effects (basically the OP’s issue) is relatively boring particularly if there are a lot of pins with different circuits. I have seen a unit catch fire during pin injection testing but fortunately it was someone else’s test being carried out at the same test house.

Robert.

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