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Another NEPA issue this week was the fuel dumping by Delta Flight 89 - https://www.flightradar24.com/blog/delta-777-dumps-fuel-on-school-during-emergency-return

Another NEPA issue this week was the fuel dumping by Delta Flight 89 - https://www.flightradar24.com/blog/delta-777-dumps-fuel-on-school-during-emergency-return-to-lax/ https://www.flightradar24.com/blog/delta-777-dumps-fuel-on-s... I feel that aviation regulators should have addressed this a hundred years ago. No aircraft that's above its maximum safe landing weight should ever have been allowed to take off. (I realize it's inconvenient to impose this regulation today. Maximum safe landing weights can be a hundred thousand pounds less than maximum safe takeoff weights.)

HeavenFox 7y ago
So every single flight should cut their capacity by hundred thousand pounds, because there's a <0.001% chance it need to dump fuel? Suppose we impose this rule. Now we will need to make up for the lost capacity by increasing the number of flights. How can that be good for the environment?
salawat 7y ago
The reason it isn't that way is because by requiring MLW==MTW, you singlehandedly neutered any attempt at fuel efficiency or range, because now you've got a plane that's carrying around an undercarriage heavy enough to land on a max fuel load all the time. So now, you're burning more gas all the time. Generally, you design systems around everything working, while leaving yourself enough room to keep your options open should anything go wrong. Until recently, that was rather infrequent.
bdonlan 7y ago
All planes can land safely at their MTOW. However, doing so may cause damage that needs repair before a subsequent flight. It also means you need more runway, which can limit your options or reduce safety margins.
rrmm 7y ago
Planes can and do land overweight. It's avoided because it risks damage and necessitates an inspection in any case. So I don't think it's an issue that needs to be addressed in general. DL89 is certainly odd. It will be investigated and addressed if necessary.

HeavenFox 7y ago

So every single flight should cut their capacity by hundred thousand pounds, because there's a <0.001% chance it need to dump fuel? Suppose we impose this rule. Now we will need to make up for the lost capacity by increasing the number of flights. How can that be good for the environment?

salawat 7y ago

The reason it isn't that way is because by requiring MLW==MTW, you singlehandedly neutered any attempt at fuel efficiency or range, because now you've got a plane that's carrying around an undercarriage heavy enough to land on a max fuel load all the time. So now, you're burning more gas all the time. Generally, you design systems around everything working, while leaving yourself enough room to keep your options open should anything go wrong. Until recently, that was rather infrequent.

bdonlan 7y ago

All planes can land safely at their MTOW. However, doing so may cause damage that needs repair before a subsequent flight. It also means you need more runway, which can limit your options or reduce safety margins.

rrmm 7y ago

Planes can and do land overweight. It's avoided because it risks damage and necessitates an inspection in any case. So I don't think it's an issue that needs to be addressed in general. DL89 is certainly odd. It will be investigated and addressed if necessary.