@TomMcW you read all that?! :D

@ymb1 Yes I did. Had me laughing my butt off!

thrust rev isn't considered for stopping distance because the main reason you might need to abort take-off is that an engine stops working

@DanHulme all-engine failure is extremely rare -- the 737 Classic certification is based on reverse thrust in the dry -- and for the other types in the wet Boeing uses half the reversers

@ymb1 I could be wrong but I thought deploying the reversers when one engine is out is inadvisable because the thrust asymmetry abruptly changes direction

i.e the left engine fails, you get a nose-left tendency, then you deploy the thrust reversers and it suddenly changes to nose-right

@DanHulme That's what I was thinking. The asymmetric thrust could cause you to go off the side. It would get more pronounced as you slowed and lost rudder authority.

Since an RTO is done below V1 it would very quickly be below Vmcg.

Btw, is the drone.se site up and running yet?

@DanHulme @TomMcW the reverse thrust is not 100%, most of it is sideways, I don't know how much is it, and on airliners.net it's also debatable, but from the same source as my answer from an illustrative graph, is looks like it's about 50%, which should be within the rudder / NWS authority below Vmcg -- of course RTOs happen for reasons other than engine failure, but I took it a step further and checked the A320's FCTM, during...

... low- and high-speed RTO with one engine out, the manuals says to select both reversers

it also says to select both even if the plane is dispatched with one INOP reverser

probably due to that runway excursion accident @Shalvenay probably remembers which one by heart :)

@ymb1 You're talking about the one on Sao Paulo?

@TomMcW yep

was rainy and in South America is as far as my memory recalls

I think it was Tam airlines and the plane crashed into their headquarters. But I might be mixing it up with a different accident

seems like 50% right? it could also be based on the clamshell (bucket) type reverser, not the cascading one

@ymb1 Yeah, roughly

anyway those are two potential good questions for the site: 1) how much is the reverse thrust? 2) are jetliner pilots trained to use reverse thrust during RTO?

@ymb1 I've forgotten if, in balanced field length, the stop from V1 and the continue from V1 are the same? We discussed this before but my brain didn't keep it

i don't remember, will have to look it up, are you asking about the distances?

Yeah, distances. I think BFL was for a derated takeoff, but I'm fuzzy

yeah I remember we talked about it here after I posted an answer on the perf benefit of derate (vs assumed temp) -- i'll find it

aviation.stackexchange.com/a/36068/14897 this one right?

@ymb1 Yeah. I forgot about the counter-intuitive effect where derate increases mtow

not sure if you've seen this aviation.stackexchange.com/a/43847/14897 but it's another performance gain trick -- same flap setting but higher V1 gives more MTOW on same runway length

* if the limiting factor is the climb weight

I remember reading that the 787-9 and/or -10 has more flap settings than the -8

makes me wonder why not go the Douglas route of dial-a-flap system

image source: airliners.net/photo/Monarch-Airlines/McDonnell-Douglas-DC-10-30/…

@ymb1 Are the flaps in the picture the white lever or the black one to the right of it?

The black one must be spoilers. I guess where it says "land ext" would be the "armed" position

@ymb1 Ameristar's MD-80 procedures call for reverse thrust during RTO (and it was apparently deployed during the reject-at-rotation at KYIP)

@Shalvenay That the one that had the jammed elevator?