Originally Posted by
tdracer
The 787 has a copper mesh embedded in the carbon fiber matrix - the wing, fuselage, pretty much everywhere. In addition - due in part to the uncertainties in the lightning characteristics of carbon fiber - they added a metallic copper foil to the inside of the wing skin. Once they had real aircraft structure to test and analyze they were better able to quantify the lightning threat. Then:
Combined with the zone change around the engine pylon, it was determined the foil was no longer needed, that the copper mesh along with the nitrogen inerting system provided adequate protection against lightning strike.
I worked with Tom Thorson - the FAA specialist quoted in the linked article - and he's reasonably sharp. But he's a Propulsion specialist, not a lightning specialist. I worked some aspects of lightning protection for 20 years, but my lightning knowledge was a small fraction of that what the Boeing (and FAA) lightning experts knew.
I used to say - somewhat joking - that I knew enough about lightning and lightning protection to be dangerous. Based on some of the posts on this thread, it appears ignorance is even more dangerous.
tdracer - I think the main issues are how Boeing have been getting to their determinations (how they have been classifying things - optimistically in favour of easy and cheap), that now justify review. Remember 20/20 the MAX would have been grounded, knowing what we know now.
That and the fact Boeing produced and delivered a large number of aircraft prior to having this change approved by the Regulator/s.
Personally I can see no justification for this change based on "over 1,000" lightning strikes, I would need to see a few more zeros.