Start with this thread[1] from HN a couple of months ago (search for "inert"). This has been a long time coming[2] and is in response to TWA 800 which was a 747 that exploded in 1996 due to lack of fuel tank inerting[3].

The FAA issued a directive in 2008 saying that by December 26, 2017 (not 2018, sorry) [4] passenger planes flying within or into the US had to have fuel tank inerting. Many operators such as Delta and United (can't find a better source for that now than this reddit comment [5]) decided not to retrofit and flew their 747s pretty much right up to the deadline.

Other operators, such as BA (presumably) have already retrofitted their 747s and will continue flying them.

So obviously Delta and United weren't very interested in flying the 747s anyway since they consider it more economical to turn them into beer cans or cargo planes than continue flying them, but the immediate reason they're stopping at this time is because they couldn't legally continue past the deadline.

Which is all I'm pointing out here, that they've known this was coming since 2008 but didn't value the safety of their passengers enough to retrofit the planes, and continued flying them right up to the deadline.

It's worth calling out corporate doublespeak and convenient omissions whenever they occur.

1. https://news.ycombinator.com/item?id=15478442

2. http://www.iasa.com.au/folders/Safety_Issues/FAA_Inaction/in...

3. https://en.wikipedia.org/wiki/TWA_Flight_800

4. https://www.faa.gov/documentLibrary/media/Advisory_Circular/...

5. https://www.reddit.com/r/aviation/comments/7bxs0x/final_unit...

The 747 without fuel tank inerting is still has a very good safety record. It's been over 20 years since one has had a fuel tank explosion. FAA estimates are without inserting a passenger jet risks a fuel tank explosion every 60M hours, or roughly every 30,000 years. Lastly, it's unclear how well the FAA inerting requirements will even work, they only reduce oxygen levels to 12%, while military jets require 9% to eliminate explosion risks.

It's silly to spend a large amount of money to retrofit planes near the end of their useful lives with safety equipment of questionable benefit. Especially when every bit of equipment introduces it's own new risks.

Agreed, overall they're safe. I'm just pointing out that the time of the phase-out in the US is effectively FAA-mandated due to the airlines not wanting to retrofit the fleet, as e.g. BA has apparently done.

This is an interesting bit of trivia, and not something you'll find in airline press releases since for better or worse it's going to make them look worse in the eyes of their customers.

There's ~500 747s[1] in service. So 30k/500 =~ 60yrs, or a 25% chance that one will blow up in the next 15 years. So this seems like a reasonable retrofit given the cost.

I assume that the FAA knows what it's doing and 12% oxygen helps, even if it's not 9%, similarly I assume they've taken into account the risk of retrofitting existing planes, since they started explicitly mandating that in 2008.

1. https://en.wikipedia.org/wiki/List_of_Boeing_747_operators#A...

Thanks. I’ll get reading.

Edit: completely agree with calling out corporate doublespeak