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Comment by fmpfmp | Hacker News Reader

Also consider that an empty battery weighs the same as a charged one. Whereas empty fuel tanks don't.

I wonder how annoying this is for the engineers to stay within landing weight limits (MLW)

My guess (I'm not an engineer) is landing weight limits are more then because the airplane will never have more than that anyway. They need a little better suspension in case of a hard landing, and different training for the aircraft (which you need anyway) to account for it handling differently, but otherwise it is still an airplane. Maybe bigger spoilers or some other part as well to better bleed off speed.

They need to account for it of course, but it seems more like account for it, not difficult. Any engineer in this space able to comment?

Landing weight limits are less than takeoff limits because of the extreme stress it puts on the landing gear. This is why planes that have an issue right after takeoff often need to dump tens of thousands of gallons of fuel before they can land.

>Aircraft have two main types of weight limits: the maximum takeoff weight is composed of dry operating weight (DOW) plus payload (passengers and cargo), collectively the zero fuel weight (ZFW), plus the trip fuel, contingency, alternate, final reserve and the block fuel (taxi fuel), and the maximum structural landing weight, with the maximum structural landing weight almost always being the lower of the two. This allows an aircraft on a normal, routine flight to take off at a higher weight, consume fuel en route, and arrive at a lower weight. [0]

[0] https://en.wikipedia.org/wiki/Fuel_dumping

> an empty battery weighs the same as a charged one

Technically, an empty battery weighs less than a charged one.

In practice, the difference is negligible.

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