The FAA has issued an update to an AD on hundreds of Boeing 777s because it’s concerned they might explode if struck by lightning. The AD was issued this week to update earlier action to address cracks in wing chords. When it reviewed the wing problems, the agency discovered that there were errors in the AD relating to the replacement of cap seals on fasteners in a section of the wing that penetrates the center fuel tank.
“If these seals are not replaced properly, and the associated fastener has poor electrical bonding to the airplane structure for any reason, the fastener may spark during a lightning strike and cause a fuel tank explosion,” the FAA said in the AD. The agency said it expects the AD to apply to 291 U.S.-registered aircraft.
Wow. This seems pretty alarmist. Don’t the stats show that on average aircraft are struck at least once a year by lightening? Doesn’t this mean that we should have seen some 777s exploding?
What is the probability of “might”?
It sounds like there’s a non-zero chance that this could happen, and there’s a known way to eliminate the possibility. Just because it hasn’t happened doesn’t mean it couldn’t (i.e. normalization of deviance).
If a 777 “could” or “might” explode on a lightening strike then I don’t want to get on one. They should be grounded until the issue is fixed (even if it is a small chance), because lightening strikes occur frequently.
I just ‘face slapped’ at you…. for God’s sake man!
Shades of TWA Flight 800 , B-747 , all over again – in a different set of circumstances of course , but ultimate outcome might be the same, 777.
This sounds like something that demands immediate attention and top priority.
It is quite a challenge to try and put this sort of problem in proper perspective for the “Monday Morning cockpit crowd” without sounding callous. Actually, airline maintenance personnel perform dozens of tasks on a repetitive basis, similar to tasks associated with this fastener, to “inspect and correct” conditions that otherwise would threaten safe operation. A problem does not rise to the level of an AD if it does not present a safety issue. My “business as usual” attitude here is not intended to make light of any maintenance task, but rather to point out that every single night in airline hangars across the country, such tasks are being repeated on hundreds of airframes.
I do remember making light of some of our “professional pilots” as a line mechanic, but the reality is that both the pilot and the mechanic often address potentially life-threatening issues in their normal course of work. The importance of understanding how critical the responsibilities of each profession are as we face people shortages at the airlines is born out by articles like this one – in spite of the huge pay differential experienced between the two positions.
Discussions on this topic used to break-out all the time at work. I once told one of our pilots that without him or some other pilot, the plane was not going anywhere, but without me and my fellow wrenches, it might not be coming back. It might be a team effort, but the quarterbacks are getting all the money and the credit.
Composite construction and the grounding problems it creates hasn’t yet erased the old all-metal mental complacency about electrical bonding that existed for decades. Hopefully we won’t have to experience some big-time disasters to hasten the process.