PerthGloryFan
Topic Author
Posts: 725
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Push Back Using Reverse Thrust

Sun Oct 29, 2000 5:52 pm

While passing through ATL in July I saw an Air Tran MD80something (definitely was not a B717) use its reverse thrust to back away from its gate and turn 90 degrees left.
Is this SOP for Air Tran or were they just in a hurry? Do any other carriers do this?
Ok, it saves the cost of tug but is it cost-effective?
Do the authorities have any view, either FAA, or equivalent, or the airport operators?
I imagine that it would be very noisy for the passengers - is there a maximum time reverse thrust can be applied before the deflectors melt or something?
Also seems it would be very noisy and windy at the gate itself - I guess ground equipment would all have to be secured - how does the glass in departure lounge windows stand up to it?
How difficult is it for the cockpit crew? Like, it's not as if they can look over their shoulder or use a rear vision mirror!
Is this practice feasible with other aircraft types, especially under wing mounted engines eg B737 or A320 family?
What about larger types, B747/757/767/777, or A300/310/330/340?
Any comments on all or some of the above would be appreciated.
Thanks
Aubrey
 
wilcharl
Posts: 1153
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RE: Push Back Using Reverse Thrust

Sun Oct 29, 2000 6:36 pm

Alota discussion on this has came up in the past. It is SOP @ Airtran to powerback with a DC-9/717 at all gates where there is adequate clearence. In atl this is all the gate except C2, and C20. DC-9CAPT gave information earlier of the cons of powerbacks. The wingwalkers and marshallers all must wear safety goggles so any FOD on the ramp does not take out their eyes. It feels like a strong wind standing out there during powerback. Not enough to blow anything major over. For the passengers sitting in the last rows, its loud but not deafining. The road that runs parallell to the taxiway must be blocked as soon as the first engine is lit off. It is defenently faster then a pushback. The DC-9/717 have a difficult tow bar to attach and unhook from the nose wheel. Establishing postive communciation via interphone is also difficult due to the abuse the headsets get. The marshaller brings the aircraft forward about 2-3 feet, to take the weight off the wheels, directs the pilot to stop, and then go into reverese thrust when the nose wheel gets to the middle of the road, the marshaller iniiates a turn pointing the direction the tail is going. This is established using handsignals prior to the powerback commennsing. after it is safely out on the taxiway, they marshall them off and give a crisp salute and normaly a friendly wave. Up in the flight deck i have watched the pilots doing the powerback and they have it down to a science. From the DC-9 manual:

Powerbacks can not be done when there is excessive water on the ramp due to traction (i forget the inch ammount)

The pilot should keep their heals on the floor and not use the brakes to stop the aircraft during powerback


Other aircraft like the 727 and F-100 are regularly powered back, The 737 was powered back in the past by some airlines, (air florida palm 90 was powered back and this was a contributing factor to the anti-ice not being set and the ironious readings in the cockpit that caused inadequate power to be applied, landing it in the potomic) Apparently EAL would power back everything up to and INCLUDING the 757..

I hope this helps


 
trintocan
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RE: Push Back Using Reverse Thrust

Sun Oct 29, 2000 9:08 pm

I have myself wondered why planes powered back at some airports and not at others - I have not really observed particular airlines having the habit of doing so. At Caribbean airports powerbacks do not occur, this in part a result of the lack of jetways at most regional airports. All aircraft needing positioning for warm-up are towed away from position to the taxiway for warm-up. Turboprop aircraft, however, start up in the ramp position and move away from there under their own power. Of late, it is only in Antigua (ANU) where I have noticed jets starting up in position and rolling off from there. Everywhere else I have been to jets are tugged out for warmup.

Trintocan.
Hop to it, fly for life!
 
calpilot
Posts: 881
Joined: Sun Oct 17, 1999 5:16 am

RE:

Mon Oct 30, 2000 1:39 am

For the history Eastern was the first US carrier to put this into SOP's for their jet aircraft...
 
Guest

RE: Push Back Using Reverse Thrust

Mon Oct 30, 2000 1:50 am

Our operations manual specifically forbids power backs. The biggest reason: FOD.
 
wilcharl
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Joined: Sun Jun 25, 2000 11:19 am

RE: Push Back Using Reverse Thrust

Mon Oct 30, 2000 6:17 am

CALPilot.. I poseted this earlier and got no response... Do you know if there is any history behind EAL adopting the powerback as SOP? I heard it involved Charlie Bryant, the IAM and him flying half way across the tarmac in Atlanta. This being because only mechanics could drive pushback tractors. This was a wild story but so many formar EAL people ahve said it. Also do you know if the 757 was indeed powered back?
 
AAR90
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RE: Push Back Using Reverse Thrust

Mon Oct 30, 2000 9:23 am

AA 757s performed powerback for the first 6 months or so, but are now prohibited due to engine FOD. I still have the training video from 1990.  
*NO CARRIER* -- A Naval Aviator's worst nightmare!
 
me
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RE: Push Back Using Reverse Thrust

Tue Oct 31, 2000 3:14 am

Approval for powerbacks is listed in the airlines Operations Specifications manual which lists all the FAA approved procedures for that specific airline. At AirTran we powerback the DC-9 and 717 whenever conditions permit. Wilcharl gave some good info.
 
calpilot
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RE: Push Back Using Reverse Thrust

Tue Oct 31, 2000 4:17 am

When I read the Auto-Bio. of Frank Borman, he said it was a "cost saving" mesure... And that yes, Charlie B. was there, and mad...

And yes they were the first to power back the B757.
 
jato
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RE: Push Back Using Reverse Thrust

Wed Nov 01, 2000 3:19 pm

i dont think the pilot of that plane will be flying for very long. thrust reversers are almost in efective at low speeds, at most large air cariers dont use them below 60 knots because they are not efective and will blow things through the compresors and cause damage.

JATO  
 
AA737-823
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RE: Push Back Using Reverse Thrust

Thu Nov 02, 2000 1:44 am

Powerbacks are used for lots of planes. Tail mounted engines would be my priority, I would NEVER want to powerback a 73, 75, 76, or whatever. Thrust reversers ARE effective, otherwise they wouldn't use it. Duh.
Also, about that not hitting the brakes on the DC-9 while poweringback... Do you know why? It is because if the plane is rolling backward, and you step on the wheel brakes, the plane falls on it's tail. That would be embarrassing.
R
 
wilcharl
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RE: Push Back Using Reverse Thrust

Thu Nov 02, 2000 8:30 am

I notice the powerback topic keeps springing up.. There msut be something intriguing about an aircraft going in reverse... I acutaly got a rush out of marshalling an aircraft during a powerback. Maybe its that that you feel as though your in command of such a big beast and the loud noise and the wind genrated. I remember once though a lav driver had an accidnet with the honey wagon on the aft lav of a DC-9 and some how the decison came down to comense with the powerback.. Needless to say there was blue water everywhere.. Those are the things I remember when Im sitting in class @ Embry Riddle wondering if my educaiton is worth it and I think i wonder how many people in this calss can say they have powered back a 717...


 
PerthGloryFan
Topic Author
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Joined: Fri Oct 27, 2000 9:48 pm

RE: Push Back Using Reverse Thrust

Fri Nov 03, 2000 6:47 pm

It's not just for any aircraft that I found this intriguing , it's jets.
I've seen DHC-4s, DHC-6s, Convair CV440s, Blackburn Beverleys (look that one up in your favourite a/c reference), ie, prop a/c reverse using reverse pitch.
Put simply in those cases the prop is still doing the same job as it does when propelling the plane forward. However, in the case of pure jets, the turbine still exhausts to the rear but the jet stream is mechanically re-directed 180 degrees.
I haven't seen this happen in my laid back corner of the world, hence my interest I what I saw at ATL.
Thanks for all the responses, I did find some of the earlier posts on this using "powerback" as the search word.
 
Gregg
Posts: 313
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RE: Push Back Using Reverse Thrust

Sat Nov 04, 2000 2:36 pm

Another powerback question.. Why do pilots always apply forward power, let the plane roll forward a foot or two, then go into reverse thrust on powerback?

 
me
Posts: 220
Joined: Sat Oct 21, 2000 4:57 am

RE: Push Back Using Reverse Thrust

Sun Nov 05, 2000 2:10 am

We roll fwd. a few feet to get off the tires flat spots. That way when we go into reverse, less power is required to get it rolling backwards.
 
wilcharl
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RE: Push Back Using Reverse Thrust

Sun Nov 05, 2000 1:36 pm

Me,

I see your one of our DC-9 Captains. wondered what you thought of powering back out of C-17 where there is no room to come forward does that make it harder to do a powerback? When I was out there this summer I would always stand to the side so they could see me up on the flight deck. Also what cities do power backs? I miss working @ airtran. I guess being a college student is more important then being a bag smasher!
 
Guest

RE: Push Back Using Reverse Thrust

Sun Nov 05, 2000 4:15 pm

I need to clear something up here....thrust reversers on an aircraft do NOT redirect the thrust directly forward., I.E. 180 degrees as was said earlier.

On the T-Tail aircraft, thrust reversers are large "buckets" of metal that mechanically swing back and "clamshell" into the exhaust stream of the engine, deflecting the thrust maybe 10-20 degrees max forward.

On underwing engines, the principal is the same but you really can't see the reversers working. Usually a sliding sleeve on the engine slides reverse, which closes off the buckets inside the tailcone, deflecting the exhaust to the sides and forward, but nowhere near directly forward, more like 10-20 degrees....
 
me
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Joined: Sat Oct 21, 2000 4:57 am

RE: Push Back Using Reverse Thrust

Wed Nov 08, 2000 4:45 am

Wilcharl:
C-17 is a tight fit. Some guys stand on top of the guard rail so we can see them wave us forward and jump down when we start back. We are authorized to powerback at most stations, however most still pushback. At some stations (newport news for example) we can only power straight back, no turns. Some don't have the room to powerback(LGA, BOS,MIA,EWR).
 
wilcharl
Posts: 1153
Joined: Sun Jun 25, 2000 11:19 am

RE: Push Back Using Reverse Thrust

Wed Nov 08, 2000 9:31 am

Me,

I think BOS is a mess no matter what   I was going to Farnborough air show and flew us up to BOS and crossed the pond on Virgin I helped them up there for a day I couldnt beleive how they twist you around to get you out of there.
 
Guest

RE: Push Back Using Reverse Thrust

Wed Nov 08, 2000 10:38 pm

MD,

Recently I was talking to a Propulsion
engineer who is employed at GE, and
he said that "he would not recommend
it because when the plane is in reverse
thrust it will blow some sh*t out & this
could be worrying when taking off"!!!
 
wilcharl
Posts: 1153
Joined: Sun Jun 25, 2000 11:19 am

RE: Push Back Using Reverse Thrust

Fri Nov 17, 2000 12:18 pm

Me... Got another powerback question to pull up this dead topic... Is there adequate clearence out of the new gates @ MCO to do a powerback? I just flew up from there tonight and we almost had planes in all three gates leaving at roughly the same time. If there is a shortage of pushbacks, are the people and conditions @ MCO favoriable for a powerback? I had a great flight up on good old 946, i always liked that bird.
 
me
Posts: 220
Joined: Sat Oct 21, 2000 4:57 am

RE:Wilcharl

Sat Nov 18, 2000 4:05 am

I dont know if we can power out of the new MCO gates. If my manual wasn't at the airport I'd look it up.
 
Ratzz
Posts: 196
Joined: Mon Sep 27, 1999 6:58 pm

RE: Push Back Using Reverse Thrust

Sat Nov 18, 2000 10:03 pm

At all swedish airports,procedures like the one described are strictly forbidden,major reason:FOD...

The bigger the a/c,the more damage would(and could)happen.
Even though the swedish airforce are doing powerbacks with their C-130´s,but only when parked on a remote and empty apron..
 
orlo3
Posts: 107
Joined: Sat Sep 02, 2000 4:04 am

RE: Push Back Using Reverse Thrust

Wed Nov 22, 2000 4:48 am

In the past two weeks, I have made three stops in Dallas where, every time, I saw AA MD-80 using reverse thrust to back up out of the gate. A total of 4 planes have done that while I was there. It is pretty interesting to watch.
 
Guest

RE: Push Back Using Reverse Thrust

Wed Nov 22, 2000 7:58 am

I thought jets like B757 and B737-300-900 didn't like to powerback because the thrust reversers only reversed about 50% of the thrust (coming off of the bypass fan). Anyone able to enlighten me?

BTW- I was on an FL B717 that powerbacked out of ATL just a few weeks ago. I agree, it is quite a rush to feel the jet inch forward, then hear the engines go to full blast and see the jetway's connection tube (sorry, don't know the technical term) blowing in your 18,500 lb. thrust fart.  
 
Guest

RE: N-156F

Thu Nov 23, 2000 2:12 pm

Read my post above....reverse thrust is nowhere near 50% of forward thrust at the same power setting....more like 10-20%. It has to do with the angle of the deflected thrust, it's NOT directly forward...
 
AIR757200
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RE: Push Back Using Reverse Thrust

Sun Nov 26, 2000 1:02 am

I too was in ATL and saw AirTran's 3 717s pushback with reversers and 2 DC9s, last week. If you notice too, the gate area where these are performed are very clean, unlike DL that have bunch of luggage carts, etc. hanging around. I'm suprised we didn't run over one.  


AIR757200
ATA/DTW
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ewr757
Posts: 354
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RE: Push Back Using Reverse Thrust

Sun Nov 26, 2000 1:11 am



We used to powerback the 727's all the time (except out of EWR).

My last trip on the 727 was a powerback out of IAH. I knew it would not only be the last time I flew the 3 holer, but the last powerback I would ever do.

 
F-WWAI
Posts: 129
Joined: Thu Dec 30, 1999 7:41 am

RE: Power Back

Fri Dec 01, 2000 10:16 pm

hmm, this quest comes up every year.
engine makers do not want you to power back on reverse, because you take dust and sand and any sh* from the ramp into the engines and you gonna blame them in a guarantee claim later on. what you always do, is taking the risk of disruption of service and aog.
t-tail aircraft with tail mounted engines are better off for this, engines exhaust and intakes are farther away from the ground => less risk of FOD.
I believe, the power back is used on airports with special ramp conditions, i.e. the ramp is build with a one per cent slope (which is actually done for better rainwater evacuation). backing on reverse thrust on the slope isn't using high engine power setting thus reducing risk of FOD. example I was told: Atlanta ?
  FW
 
L-188
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RE: Push Back Using Reverse Thrust

Fri Dec 01, 2000 11:18 pm

The slope of the ground probably helps....But I have seen 727's powerback on an uphill slope.
OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.
 
767ALLTHEWAY
Posts: 636
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RE: Push Back Using Reverse Thrust

Sat Dec 02, 2000 2:31 am

At KMHT, in August two SWA 737-300's left around the same time. The first one to leave was pushed back by a tug. And the second one did a powerback, even though it was raining. Why would one do this and the other aircraft didnt.?
-767ALLTHEWAY
"Courage is not the absence of fear, but rather the judgement that something else is more important than fear"
 
access-air
Posts: 1576
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RE: Push Back Using Reverse Thrust

Mon Dec 11, 2000 4:21 am

Wasnt Eastern Airlines the pioneer of the powerback???
I have been on a couple of TWA DC9 flights that performed powerbacks off the old Ozark Airplex in STL......in fact i have one tape recorded as i used to do that on most of my earlier passenger flights......it is cool and too i must admit!!!! ive seen it even done in Moline by a Northwest DC9-30...its kind of loud from outside!!!!
anyway, those are my two cents worth... 

AccessAir
Remember, Wherever you go, there you are!!!!
 
wilcharl
Posts: 1153
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RE: Push Back Using Reverse Thrust

Mon Dec 11, 2000 6:55 am

i have never seen or heard of SWA doing a powerback, but i would love to see it... Air Florida and Frontier I did them in 737s. I know that SWA only mechanics push planes (the same as EAL) but i have no clue what SWA's sop is for getting a plane out of a gate other then to get it in and out as fast as possible.

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