IAH744
Topic Author
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How Does A Plane Powerback?

Tue Dec 20, 2005 12:08 pm

hello,

Just wondering how 727/md-80/dc-9 type aircraft "powerback"


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I never thought bucket reverse redirected enough power to push an aircraft backwards.
Is there something else that helps?

heres a video
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EMBQA
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RE: How Does A Plane Powerback?

Tue Dec 20, 2005 12:12 pm

Quoting IAH744 (Thread starter):
I never thought bucket reverse redirected enough power to push an aircraft backwards.
Is there something else that helps?

Oh, heck yea it will. You apply slight fwd thrust, then pull reverse thrust. The reverse thrust will back the aircraft out. You need to be careful with the amount of thrust applied and the breaking as you can put the plane on its tail if your not careful.
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skysurfer
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RE: How Does A Plane Powerback?

Tue Dec 20, 2005 12:20 pm

I did this last year on an NWA DC-9 at MSP......slight roll forward, then the buckets are deployed and back we go. Light braking to stop (as EMBQA rightly said, too hard and you'll end up on the tail) and after the buckets are stowed away you go. Waste of fuel? Maybe. But if there's no tug available then it's more than worth it using fuel for a 10-20 second powerback. I'm glad i experienced one.

Cheers
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phxplanes
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RE: How Does A Plane Powerback?

Tue Dec 20, 2005 12:48 pm

Thats something you don't see everyday, kinda cool. What is the purpose? Wouldn't it not be as safe. It seems like it might be more convenient though. Also how do they decide when to do it.

Thanks
 
EMBQA
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RE: How Does A Plane Powerback?

Tue Dec 20, 2005 1:00 pm

Quoting Phxplanes (Reply 3):
Thats something you don't see everyday

..?? You see that all the time at airports that have DC-9's, MD-80's and 727's.... it's a very common practice when push back tugs are not available.
"It's not the size of the dog in the fight, but the size of the fight in the dog"
 
goboeing
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RE: How Does A Plane Powerback?

Tue Dec 20, 2005 1:18 pm

Northwest only permits powerbacks at the three hubs that DC-9s visit - MSP, DTW, and MEM. Furthermore, there are gates at each of those airports that powerbacks are not allowed to be performed from (too small an alley, close side-by-side arrangements, etc.).

The pilots know beforehand from the ground crew if they'll be doing a powerback and they inform ramp control of this upon initial contact after receiving the clearance. When the clearance for the powerback is given the ramper in front of the cockpit gives the ready-to-go signal and puts his goggles on.

Both pilots take their feet off of the rudder pedals and put them on the floor. The captain pushes the power just enough to breakaway thrust and rolls the jet forward a few feet to get the tires off of the soft spots so that minimal reverse thrust is needed. After moving forward these couple of feet, he or she goes back to idle and thing brings both engines into reverse thrust and keeps an eye on the ramper ahead of the cockpit who is now giving the both-hands-twirling "continue powering back" signal. I was pretty surprised at how fast it moves backwards after watching it the first few times from the jumpseat. It continues and the two wingwalkers will give a signal to the cockpit ramper that it's time to stop. He will signal that to the cockpit and the captain takes off the reverse thrust and lets idle thrust bring the jet to a stop. A little forward thrust and by this time the FO is already getting the taxi clearance.

Nick
 
OttoPylit
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RE: How Does A Plane Powerback?

Tue Dec 20, 2005 1:28 pm

Who says powerbacks have to be limited to DC-9 series aircraft? 737-200's are fully capable of powerbacks, as long as you are willing to suffer the consequences of everything on the ramp not secured down by steel pilings to be sucked into the engines, such as halon fire extinguishers, chocks, ramp agents, orange cones, and wands.  rotfl 


The pilot of Palm 90 attempted to help the ground crew during pushback by using the reverse thrusters to get the plane moving. All he managed to end up doing was throw more ice and slush up onto the tops of the wings, which were to play a part in its fall from the sky over Washington D.C. shortly afterward on January 13, 1982.


OttoPylit
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dalb777
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RE: How Does A Plane Powerback?

Tue Dec 20, 2005 3:32 pm

So I take it that a plane has to have buckets in order to powerback. Can a plane without buckets powerback?
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IAH744
Topic Author
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RE: How Does A Plane Powerback?

Tue Dec 20, 2005 3:34 pm

Quoting Dalb777 (Reply 7):
So I take it that a plane has to have buckets in order to powerback. Can a plane without buckets powerback?

dont think the older 27s have them
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kaitak744
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RE: How Does A Plane Powerback?

Tue Dec 20, 2005 3:52 pm

The reason they don't do this on larger aircraft is because the thurst can blow the terminal windows.
 
crogalski
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RE: How Does A Plane Powerback?

Tue Dec 20, 2005 5:08 pm

I saw a airtran 717 do it the other day.
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PMN
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RE: How Does A Plane Powerback?

Tue Dec 20, 2005 7:51 pm

Quoting Dalb777 (Reply 7):
Can a plane without buckets powerback?

I'm sure I've read in similar threads here in the past that pretty much any aircraft equipped with thrust reversers can power back, it just isn't practiced on aircraft with under wing mounted engines for various reasons. I'm sure someone here can offer a more in depth explanation.

Paul
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