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kbuf737
Topic Author
Posts: 765
Joined: Thu Dec 04, 2003 2:22 pm

Power Backing

Thu Dec 11, 2003 3:10 pm

Is powerbacking widely used? And can any airplane simply powerback if it desires? I would think that only planes with clamshells can powerback effectively?
 
modesto2
Posts: 2731
Joined: Sun Jul 16, 2000 3:44 am

RE: Power Backing

Thu Dec 11, 2003 5:39 pm

I've only seen pictures of tail-mounted engine aircraft (such as the DC-9) perform this operation.
 
FLY 8
Posts: 330
Joined: Sat Dec 02, 2000 5:48 am

RE: Power Backing

Thu Dec 11, 2003 6:45 pm

We do it with the Dornier 328 all the time!
 
Rick767
Posts: 2613
Joined: Sun Jan 30, 2000 8:11 pm

RE: Power Backing

Thu Dec 11, 2003 8:13 pm

Generally a tail-mounted engine operation, but it is an approved procedure on the 737 and 757 too. Not the 767 though.
 
GE
Posts: 312
Joined: Sun Mar 26, 2000 5:01 pm

RE: Power Backing

Thu Dec 11, 2003 11:19 pm

Rick:
Won't doing a power-back in a 737 be quite dangerous as the engines are quite low to the ground?
Have you done a power-back before?
Thanks.  Smile

Regards,
Russell
 
goingboeing
Posts: 4727
Joined: Sat Dec 04, 1999 1:58 am

RE: Power Backing

Thu Dec 11, 2003 11:55 pm

I was in a 737-300 on Southwest which powerbacked out of the gate at OAK.
 
kbuf737
Topic Author
Posts: 765
Joined: Thu Dec 04, 2003 2:22 pm

RE: Power Backing

Fri Dec 12, 2003 4:04 am

never thought you could powerback a 737. I guess my only experience with attempting to do so is in FlightSim and it just doesnt happen. Isn't there an FOD threat though?
 
PSAjet17
Posts: 375
Joined: Thu Dec 11, 2003 5:50 am

RE: Power Backing In FlightSim

Fri Dec 12, 2003 6:07 am

If you are going to do that in FS you need to edit your aircraft.cfg, in the
General Engine Data add/modify the min_throttle_limit like below. I think the default for most jets is set at -0.25 but -0.40 usually is powerful enought to make her backup.


[GeneralEngineData]
min_throttle_limit=-0.40
 
kbuf737
Topic Author
Posts: 765
Joined: Thu Dec 04, 2003 2:22 pm

RE: Power Backing

Fri Dec 12, 2003 6:54 am

Thanks PSA, I'll give it a go. I remember in the old days you could powerback the lear, but we are talking FS 5.1 here.
 
Ops48
Posts: 61
Joined: Sun Sep 21, 2003 4:01 am

RE: Power Backing

Fri Dec 12, 2003 7:31 am

Here at DEN, powerbacks are tightly controlled through letters of agreement between the City and County of Denver and airlines that use the airport. At this time, only NW, AA, CO and F9 have LOA's authorizing powerbacks. The LOA's place operational guidelines and limitations on powerbacks. The area around aircraft powering back must be carefully inspected for FOD, equipment must be moved from the area, powerbacks cannot be performed in the rain or snow or when there is standing water or snow on the ramp, surface wind velocity cannot exceed 25 knots, and powerbacks are not approved for widebodies or four-engine aircraft.

I'm sure that the individual air carriers have company policy regarding powerbacks as well. Don't forget that the ingestion of snow and ice during powerback was a contributing factor to the Air Florida Palm 90 crash.
 
USAFHummer
Posts: 10261
Joined: Thu May 18, 2000 12:22 pm

RE: Power Backing

Fri Dec 12, 2003 1:04 pm

DFW is powerback central...it is very common there with AA and all their MD-80's...

Greg
 
L-188
Posts: 29881
Joined: Wed Jul 07, 1999 11:27 am

RE: Power Backing

Fri Dec 12, 2003 2:00 pm

Markair took out a window on the Anchorage International Airport one time back in the late 80's doing a powerback with a 737-200
 
kbuf737
Topic Author
Posts: 765
Joined: Thu Dec 04, 2003 2:22 pm

RE: Power Backing

Fri Dec 12, 2003 2:41 pm

Picture a 777 with the GE-90s trying to powerback! what a beast!
 
L-188
Posts: 29881
Joined: Wed Jul 07, 1999 11:27 am

RE: Power Backing

Fri Dec 12, 2003 4:03 pm

Actually the most impressive displays of backing aircraft up I have found don't come from turbine aircraft but from prop jobs.

Had an Electra back up one time on fresh snow. It was at night and they had the wing lights on but still retracted.

Man what a light show. Very cool.


The jet powerback that I heard about but nobody seems to gathered on tape happened in Reno about 6 or 7 years ago when the airport flooded. Apparently Reno Air had two MD-80's that where sitting in about two feet of water at the gate and only one working tug to move the airplanes before it got deeper.

Anyway the tug took one of the aircraft and an off-duty captain moved the other one.

I understand the powerback he did to get off the gate through roostertails 50 or 60 feet into the air!


Man I wish somebody got that on tape, or at the very least can confirm this story  Wink/being sarcastic
 
SlamClick
Posts: 9576
Joined: Sun Nov 23, 2003 7:09 am

RE: Power Backing

Sat Dec 13, 2003 10:53 pm

It is possible to back up a BAe-146 which does not have thrust reversers.

Hold the left brake on almost full. Turn the nosewheel to the left. Run up number 1 engine with the rest at idle. This will pivot the plane about the left mains and back the right mains a few feet.

Now release the left brake, hold the right brake, turn the nosewheel to the right and run up number four.

I might do this to back away from a burning building or something but certainly not in normal ops. It is a modification of a procedure used by some B-17 pilots.

IMO powerback with passengers aboard is a bad idea. It costs more money in ground guide salaries and shortened engine life than it ever saved in pushback crews. It is noisy and scares the passengers. In the first month of powerbacks, one airline hit a cinderblock wall and another airplane.



 
DeltaMD11
Posts: 1680
Joined: Sat Dec 07, 2002 4:56 am

RE: Power Backing

Sun Dec 14, 2003 12:20 am

Here is a procedural question:
When performing a powerback is it procedure to disengage the reversers and add a bit of forward thrust to arrest the aircrafts' backward motion, or can you simply disengage the reversers and tamp down on the brakes to bring her to a stop? I ask this because within the right conditions you could potentially bring the aircraft down on her tail (especially so for tail-mounted twins like the DC-9/717/MD-80 etc.).

Thanks.
 
USAFHummer
Posts: 10261
Joined: Thu May 18, 2000 12:22 pm

RE: Power Backing

Sun Dec 14, 2003 1:14 am

As you correctly stated Bryan, hitting the brakes to stop a powerback will probably put the plane on its tail, so forward thrust is used...

My question is...could a stop be done with brakes if the application was gradual (not that it would be practical since it would take too long to stop I would assume)...

Greg
 
musang
Posts: 818
Joined: Sun Apr 08, 2001 4:11 am

RE: Power Backing

Sun Dec 14, 2003 8:15 pm

Answer is Yes, but if its a jet, selecting forward idle would provide residual forward thrust to stop it. It wouldn't be going very fast! If its a turboprop, power levers to idle produces zero thrust so levers slightly forward would be required. It's approved on ATRs, and I once reversed a Do228 back to the edge of the grass.

One often sees biz-jets (no ingestion risk) taxiing with a TR open simply to avoid riding the brakes or having to slow down every so often. Many jets, once moving, will continue to accelerate at idle thrust to an excessive speed. A 777 pilot once told me that engineering told him that each brake application (to bring it back to walking pace) cost £10!

When I was a despatcher I remember one icy night the tug couldn't get enough purchase on stand 17 at Gatwick to push the Uganda 707 out. Its slightly uphill. So the tug crew requested he select reverse on an engine. No luck. Another engine - still no success. It eventually started to go backward when all four were in idle reverse!

Regards - Musang

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