80ktsClamp

It was done a few years ago... the savings was quite significant accross the board.



Everyone is waiting on your to go all latin on me.

Carl Spackler

Yup...it was a Delta study alright. Everyone is wearing their hats.

Carl

Ferd149

I'll admit to being a solid C physics student, but I do understand momentum. This is what I was saying in the other thread, I'm not seeing the savings taxi out as two in idle has to be about the same as one at a higher setting.

TSquare says Delta looked at it 15 years ago, and we're wrong. So I guess there are figures somewhere.

80ktsClamp

If your captains are taxiing it right, breakaway thrust at single engine is basically the same as two engines on the 757. It doesn't take more than idle thrust to keep going in the 757 at anytime single engine unless it's a steep hill.

80ktsClamp

We need ftb to big bird in some widgets on those badboys... except dark helmet, he gets an airmail logo.

Carl Spackler

That's just not what I see in ATL clamp. The 757's I commute on spend a lot of time with some high power settings. The MD is even worse. I'd just like to see actual data from a side by side test.

Carl

skybolt

Spirit std is s.e.taxi. In the four years I've been a babybus Cpt, I can't remember more than a few times that a second engine was necessary to taxi. In fact, one turning in a 319 loaded up with 145 pax, and fuel for FLL LGA takes little more than idle thrust to break away and gives a nice ten or so knot taxi which requires very little braking. We use the APU to start #2 which eliminates the crossbleed problem.

Funny thing, I always assumed that s.e.taxi was a NWA thing because Jeff Carlson started it at Spirit.

Truthfully, I started using it mostly because they load so little fuel up, I hated to burn that "six hundred pounds for momma and the kids" up just sitting around on taxi out. Then I discovered that it really made things easier.

cactusmike

At AWA we used single engine taxi somewhat, but after fuel spiked over the last couple of years there has been a real big push for single engine taxi. We did it a lot on the 757 because we were Brake release fuel limited on some of our flights to Hawaii (we had some 240k GTOW jets with full loads). I did not think much of the idea (our previous PH discouraged SE taxi over 205K) but after flight ops engineering talked to Boeing they said it was OK up to Max TOW. I never had an issue with breakaway thrust, especially since we have gone to all concrete taxiways in PHX.

On the Airbus standard procedure is SE taxi. I would think there might be an issue in ATL because you have some pretty good slopes on those taxiways. But for us in PHX, PHL or most other places it works just great. I like having fuel in my tanks without carrying a lot of unecessary extra fuel. Sitting # 25 in JFK saves a lot of gas.

One thing about shutting down the APU and cross bleeding the other engine start - if it is warm out there is more airflow and less fuel burned by running the APU bleed.

aa73

A-men brother. Apparently it must be Utopia working for airlines like DL where everyone sings kumbaya together.

Until AA management actually shares profit sharing with us and stops stealing from us to enrich their own coffers, they can shove their S.E. taxi where it's dark and gloomy.

Two engine taxi out with APU for takeoff, two engine taxi in and APU stays on at all times at the gate. Safety first, crew/pax comfort second, fuel savings = FUPM!!

reddog25

Don't know about the 757. The SE discussions seemed to have been prompted by those surley 320 aviators. Very rarely do you need to be higher than idle during taxi on eng#1. If you find your self above 44% for the #1 engine then I would say yes, as 44% is almost twice that of 22%

Never took physics...and I'm just a dumb rotor head.