B737 - self reversing from stand

[tb10er]

Watching the news about the hurricane at New Orleans, I started thinking about a visit I made there in the 80's.

I seem to remember that B737's were able to do their own-push back and reverse from the stand.

In all of the years since, and several hundred airports, I haven't seen this done anywhere else.

Did I dream this?

[BOAC]

Cannot speak for N O but it used to be a 'specifically-authorised pilots only' manoeuvre for the 737-100/200 but verboten on the 300 onwards due to the high risk of debris ingestion/engine surge.

I guess in a real emergency I would still do it but I must remember not to stop using the brakes............ :D

[Sky_Captain]

As always BOAC is correct. Had the pleasure of marshalling a 737/200 off of stand about 4 years ago. It was based in Africa and the front gear had a particular pair of ski's connected to it for landing in dessert conditions, thus not allowing any towbar to be connected.

Don't really see much of that any more, all you get nowaday's is Ryanairs 737/200s using reverse thrust along the taxi ways to slow them down from 90kts taxi speed :p

S.C. :ok:

[Piltdown Man]

I'd recon that (in extremis) any aircraft with reverse thrust could "power back". As to whether or not is allowed by the AOM (for the good reasons mentioned earlier) or God's Gods of Aviation (the local airport managers) is a different matter. Going back a few years, an Aeroflot IL62 did it's own "pushback" at LHR (there was some dispute with the Soviets) and they were refused ground handling.

However, it's amazing how quickly the rules change when you are blocking a stand which is required!

[Global Pilot]

USAF C5s all self pushed on their recent visits to Shannon. Very impressive to watch. Not sure if it was because the gorund equipment wasn't avail for a tug to push them back. Couple of pallets wobbled on the ramp as the engines powered up!

Saw this Jetstream 41 pushing itself back at Ronaldsway last week during a brief visit there. Looked great seeing it in action.

http://www.airliners.net/open.file?id=833053&WxsIERv=Oevgvfu%20Nrebfcnpr%20Wrgfgernz%2041&Wm=0&WdsYXMg=Rnfgrea%20Nvejnlf&QtODMg=Vfyr%20bs%20Zna%20-%20Ebanyqfjnl%20%28VBZ%20%2F%20RTAF%29&ERDLTkt=HX%20-%20Vfyr%20bs%20Zna&ktODMp=Ncevy%2029%2C%202005&BP=1&WNEb25u=Naqerj%20Znexf&xsIERvdWdsY=T-ZNWR&MgTUQtODMgKE=&YXMgTUQtODMgKERD=60&NEb25uZWxs=2005-05-08%2004%3A19%3A05&ODJ9dvCE=&O89Dcjdg=41007&static=yes&width=1024&height=719&sok=JURER%20%20%28ZNGPU%20%28nvepensg%2Cnveyvar%2Ccynpr%2Ccu bgb_qngr%2Cpbhagel%2Cerznex%2Ccubgbtencure%2Crznvy%2Clrne%2C ert%2Cnvepensg_trarevp%2Cpa%2Cpbqr%29%20NTNVAFG%20%28%27%2B% 22ebanyqfjnl%22%27%20VA%20OBBYRNA%20ZBQR%29%29%20%20beqre%20 ol%20cubgb_vq%20QRFP&photo_nr=29&prev_id=833771&next_id=832971

[lomapaseo]

Makes a difference on what power is needed to get the tyres rolling vs inlet lip height from the ground to avoid vortex entry into the engine.

Once you get it moving the problem of reingestion/surge disappear when you're moving backward under reverse thrust.

[Dry Thunder]

I can only say for a B737-200, it’s not a recommended procedure, however the aircraft can physically do it. It has being successfully done at max all up weight on a level surface out of a bay and partially turned into the lane. At most African airports simple things like tugs/ tow bars / Tow link fitting are luxury items. I also heard a KLM 747 had done it at a African airport. forced to divert due wx.

[Grunf]

Hello.

For 737 after Series 200 this is not a valid loadcase analyzed because of several warnings from regulatory bodies (FAA and other CAAs).

Therefore it is not a recommended practice. Of course, you can do it, probably on all 737s, including NGs but…

I you have any kind of structural issues with this you will get a "we told you" type of answer.

Usually, this is never a ground loadcase you're looking into.

Nor is, when we talk about these things, riding on tarmac with one engine shut off (Air Canada pilots on CRJ 200 loved this practice)!

Cheers

[CaptainSandL]

Dont forget the Air Florida accident at Washington in 1982. Part of the reason for the snow accumulation on the wings was thought to be that it was blown up from the ramp during power back.

[VH-Cheer Up]

Not just 737's either in the USA. I've seen it done on DC9's and 727s extensively (and exclusively - no tugs used anywhere in sight in those days) at St Louis, Mo.

Also witnessed it at Atlanta, LaGuardia and ORD although not exclusive means of pushback. I'm talking 1976-78 timeframe, don't remember seeing it done in the 80's, but you know what they say.

[fireflybob]

Reminds me of the day at MAN circa 1982 when Captain was advised by agent that he would not be able to depart as pushback crew on strike.

Well, you have guessed it they backed off the stand with lookouts and permission from the Airport Authority.

When I did me B707 P2 to P1 Upgrade at Prestwick (about 1974 ish) we were taught how to move the aircraft backwards with use of reverse. Great fun! Main thing is not to touch the brakes - just cancel reverse when you want to stop and, obviously, make sure all is clear behind.

If icing conditions such as snow etc prevail then, if my memory is correct, ANY selection of reverse means back to the ramp for another deice - post the B737 accident at Washington.

[TheOddOne]

Pan-Am had it as an SOP at Heathrow with their German route 727s in the 1980's, presumably to save money when they were on their last legs. No drama with the high engines, just used 1 & 3 as I recall.

Never saw a Trident try it.

We officially disapprove of it at Gatwick, though as Piltdown Man says, amazing how expediency can change things! There's no reason why we can't do it, we do need to see that there's no alternative pushback arrangement available before approving it.

We did once literally push an Embraer once with half a dozen blokes on the leading edge; wasn't very difficult to get moving. However, the following day the a/c Commander had obviously thought about the potential damage to his leading edges and we had to clear an adjacent stand so it could 'spin' out instead.

Cheers,

The Odd One

[PAXboy]

When my nephew was driving J41s, they would often powerback and the precaution was to just blip the throttle to break out and then close and drift. Once she had stopped THEN apply the brakes and prepare to move forward. As I recall, the intakes for the Garretts (I think they are) face slightly up.

[barit1]

At ATL about 1985, two Eastern DC-9's backed into each other from opposing gates.

[Techman]

It's fine if you have a turboprop or low-bypass jet with bucket or cascade vanes. But please don't try it with a hi-bypass with fan reversers. That is just looking for trouble.

[rubik101]

Many moons ago a Super Constellation AEW landed at Lossiemouth for a joint exercise with the RAF. Come the time to taxy out, the marshaller thought the space to turn was too tight so he signalled the Connie to reverse, all quite legal for the aircraft so to do. After a few frowns from the flight crew, the F/E set reverse and wound on 1200RPM. The result was that the marshaller was sent about 40m across the apron. He suffered nothing more than a loss of dignity and dirty fingernails!

[AirRabbit]

Originally posted by CaptainSandL
Dont forget the Air Florida accident at Washington in 1982. Part of the reason for the snow accumulation on the wings was thought to be that it was blown up from the ramp during power back.
That airplane did not “power back.” The Captain opened the thrust reversers (with idle thrust) in an effort to assist the tug in “pushing back” with the engines running and the tug slipping on the ground just after having the airplane “de-iced.” That didn’t work. So the Captain shut down the engines and they got a larger tug to push them back. The accumulation of ice on the wings was not due to “blow up” from the ground as alleged; it was due to the improper de-icing procedures performed with only 3% glycol solution and 160 degree heated water.

[GrahamCurry]

>At ATL about 1985, two Eastern DC-9's backed into each other from opposing gates.

You mean they weren't looking in their mirrors?

[doubleu-anker]

Risky to say the least. 2 reasons.

1/ If the A/C is braked using wheel brakes, then the chances of it sitting on it's a**** are high.

2/ When reverse is used at low speeds or stationary, then the risk of injestion, therefore FOD damage is high.

The crew will not know the extent of this damage untill the engines are stationary and a visual inspection of the 1st stage fan is carried out.

[john_tullamarine]

I recall my Electra endorsement many moons ago and the IP's demo of taxyway 3-point turns. Couldn't see all that much as the whole endorsement was done at night due availability (which was a bit naughty in itself) but the demo was impressive.

[172driver]

experienced it a number of times out of DFW in the 80s, MD80s, if memory serves me well. Seems to have been SOP there for AA at the time if recalling conversations with one of their captains correctly.

[GOLF-INDIA BRAVO]

Remember being at Minneapolis and powering back on a B727, funny watching a DC-9 get it wrong and have to taxi forward again onto stand and have another go getting the right direction
Northwest seemed to do it all the time as
in an hours or so saw quite a large number

G-I-B

[CaptainSandL]

AirRabbit

I stand corrected it was not a true self manouvered power back.
Nevertheless the accident report states on page 3 re the first failed pushback:

“Witnesses estimated that both engines were operated in reverse for a period of 30 to 90 seconds. During this time, several Air Florida and American Airlines personnel observed snow and/or slush being blown toward the front of the aircraft.”

It then goes on to give various other eyewitness reports of whether snow was seen or not on the wings after pushback.

Either way, my point was that the use of reverse thrust before departure in contaminated/icing conditions is a bad move.

S & L

[PAXboy]

It seems that the high engined a/c can do this with greater safety.

My nephew used to drive Jetstream 41s (not in UK) and they did powerbacks all the time. He said, Change pitch and brakes off. Crack the throttle and as soon as she breaks out, close it again. If needs be, give another blip. When she has stopped, change pitch and apply brakes.

[AirRabbit]

CaptainSandL:

“Witnesses estimated that both engines were operated in reverse for a period of 30 to 90 seconds. During this time, several Air Florida and American Airlines personnel observed snow and/or slush being blown toward the front of the aircraft.”

It then goes on to give various other eyewitness reports of whether snow was seen or not on the wings after pushback.
Either way, my point was that the use of reverse thrust before departure in contaminated/icing conditions is a bad move.
I wasn't disagreeing with the point you were making and I'm quite familiar with the accident report. Until this accident, I was a very strong believer in the non-biased approach of accident investigation organizations, particularly when they are governmental agencies; and I continue to have zero problems with finding the facts behind an accident or incident -- regardless of what they might be.

Unfortunately, the report of this particular accident doesn't tell all the facts and it reaches conclusions (leading to statements of "probable cause" and "contributing causes") which are not accurate. In fact, in some cases, the contridictions to the conclusions are part of the "factual report;" they're just ignored.

The cause of the accident was the leading edge of the wings being contaminated with clear, hard ice, and were, therefore, deformed to the extent that only the inboard portion of the wing generated lift at the airspeeds where the crew was preparing the airplane to fly (just prior to rotation). The outboard portion of the wings would not generate lift with that deformation until achieving airspeeds well beyond where the airplane became airborne. This asymmetry in lift (inboard = forward and outboard = aft) caused the airplane to "rotate" itself (beyond the control capability of the crew) and achieved a pitch of approximately 22 to 24 degrees nose up, from which the crew was unable to recover. The ice on the wing leading edges did not come from the inclement weather (other than the temperature); it came from the improper de-icing process during which the airplane was "de-iced" with 160 degree water and a 3% glycol solution.

I am pleased that the information generated from this accident has caused ground crew and flight crew alike to be more aware of de-icing procedures, hold-over times, etc. But when someone comments about the "facts" of the accident and innocently believes the "factual report," I try to set the record straight. A daunting task, but one that I believe in.