B737 taxi with one eng.

[Visionman]

Hello everybody! I want to know,please, if there is any company which has a special procedure for taxing a B737 with one engine shut off for fuel economy! If yes,what is that procedure? Do you think it really make a fuel saveing? Any difference between clasic and NG?
Thanks!

[FCS Explorer]

after LD and after 2 min cooling you can cut 1 eng. restrictions apply: sharp turns, slope, contaminated taxi ways etc
and we are *supposed* to start the APU and take it on bus. isn't it strange how you can fly with one eng, but need the apu for taxi!?

[CHfour]

My company started this a few months ago. We wait 3 minutes after landing to allow engine to cool and make sure the APU is on the busses. If you're light and have a long taxi in (eg 18R @ AMS) it probably saves fuel and riding the brakes but if you're heavy its hard to see any saving as you have to spool up the remaining engine quite a bit and the fuel flow is doulble the idle value. It's also handy on some bridges as it prevents the left engine from ingesting debris (on a 500 the #1 gets very close to the jetty as you park)

[Rainboe]

isn't it strange how you can fly with one eng, but need the apu for taxi!?
What's strange is that statement! Are you really allowed to fly a twin on one engine with APU shut down?

[Kirks gusset]

Toxic.. Simple answer YES!

[Denti]

Single engine taxi-out is not done and no procedure exists in my company. Single engine taxi-in on the other hand is allowed if the plane is under a certain max weight (300/500 46t, 700 50t, 800 57t) and after a cooling period of three minutes. The apu is started as part of the normal taxi-in procedure anyway, besides one engine supplies both electric hydraulic pumps with power, each engine powers one brake system and the brake accumulator allows several brake applications if all hydraulic power is lost. All in all not really critical and has been done for the last 10 years.

[Denti]

Quote:
isn't it strange how you can fly with one eng, but need the apu for taxi!?

What's strange is that statement! Are you really allowed to fly a twin on one engine with APU shut down?

Of course. Otherwise dispatch without APU wouldn't be possible. That's the reason why the relevant checklists state APU (if availabe)... Start and on bus.

[Cough]

Hang on. The single engine flight vs single engine taxi is a completely different discussion. I'm gonna have a rough stab in the dark here but single engine taxi would be a planned operation (hence redundancy required) but single engine flight in revenue service is a completely different ball game.

Single engine taxi in a 737 with the way the hydraulics are set up is a no brainer. Loose the engine and you have the APU supplying both hydraulic systems. Loose the APU and both are still supplied.

Single engine taxi in at AMS 18R always saved me 100kg....Its worth while.

[Visionman]

Thank you all,guys! But seems to me that very few of us is using this procedure.All of you that use this,do you have a checklist for that? Is it a special procedure in your company SOP? I know is not really a big thing but it need a procedure,doesn t it?

[Denti]

No, pure airmanship is enough. No special procedure for us and we do use it, at least for taxi in. Taxi-out might be another thing as you have to assure a sufficient warm-up time before you can set take-off power.

[A37575]

Single engine taxi in at AMS 18R always saved me 100kg....Its worth while.

Long term problem is the side-load on the nosewheel assembly caused by continuous nose-wheel steering pressure. Several times a day may save a few kilos of fuel but the unknown is the strain on the NW assembly over a long period of time. This is another example where what was considered good airmanship (two engine taxy) has been conveniently disregarded by the bean-counters.

[Canuckbirdstrike]

Actually, the issue of landing gear loads with engine out taxi has been examined and it is a non-event. The incremental load difference for engine out taxi is very small and the specs for undercarriage loading are very robust. there are many other events that put far higher stresses on undercarriage components.

The whole issue of landing gear loads for engine out taxi is an urban legend promulgated by "concerns" not based in fact.

Lots of operators do single engine taxi in and out. Yes, it requires thought, good SOP's and training. Like any other tool in a pilots tool box it has a time and place to be used. It also saves significant dollars that at the end of the day contribute to the financial health of the airline - something we all need to ensure we have a job.

[Capt. Inop]

NG-fleet only, allow 2 min. for cooldown, APU up and running and on bus, shut down #2 (make sure there's no 90+ degree turns :})

Taxi out both donks runnining (even on AMS) APU on captains discression.

[Visionman]

Ok! But why shut down eng no2 and not eng no1?

[787FOCAL]

Engine rotating to the right.

[Canuckbirdstrike]

Which engine to shutdown is a function of hydraulic and electrical system architecture. Manufacturer's provide guidance on this in the FCOM. Some aircraft are sophisticated enough, or have good SOP's, that this is a moot point and you can shut down either engine and then the choice should be driven on taxi turning direction.

[BOAC]

the choice should be driven on taxi turning direction. - and BA's favourite trick at LGW was to change your stand as you came in, and then not have it 'ready' so you had to stop before entry........................:ugh: At this point I gave up the one-engine stuff.

[BUGS/BEARINGS/BOXES]

- and BA's favourite trick at LGW was to change your stand as you came in, and then not have it 'ready' so you had to stop before entry........................:ugh: At this point I gave up the one-engine stuff.

Well said Nigel. but then no difference in MAN either these days! :rolleyes:

[A37575]

It also saves significant dollars that at the end of the day contribute to the financial health of the airline - something we all need to ensure we have a job.

Rumour has it that Boeing are looking at using reverse thrust (737NG) for backing out of airbridge positions rather than using tugs to push back. The cost savings is significant by eliminating need for tug drivers (saving in union driven high salaries, overtime, and other workers benefits) Single engine reverse is being considered to save fuel but the extra thrust means higher fuel consumption so at this stage two engine reverse appears the go. One company is known to be looking into the possibility of employing deaf and dumb marshallers or wing tip walkers during the push back process. This offers considerable savings on radio headsets now used during push back. Sign language manuals will be issued to flight crew.

Amazing what operational measures can be taken to contribute to the financial health of the airline - something we all need to ensure we have a job...:ok:

[ClimbSequence]

As far as I remember the Flight Crew Training manual states that taxiing on one engine is "not recommended"

[TheWanderer]

Taxi in on one engine is no problem at all as it has been said earlier.

However, taxi back does not seem to be a good idea to me.
Unlike high wing turboprops like ATR, the engines on the Boeings are closer to the ground and a taxi back will have a great risk of FOD due to ingestion of dust and small stones on the apron that are blown up by your own engine's reversers.

[oceancrosser]

As far as I remember the Flight Crew Training manual states that taxiing on one engine is "not recommended"

Not anymore, at least for 757/767. Due to pressure from operators Boeing changed its stance and now we have a chapter title "Engine Out Taxi" in the FCTM.

[Bullwinklejmoose]

The reason you want to shut down No.2 engine on taxi in is
so the ground personnel can open the cargo doors and get
the bags out pronto. Guess what side the cargo doors are on?:cool:

[Visionman]

It will take you one sec to shut down eng no2.So,I don t think this is a good and realistic point of view.

[Capt. Inop]

Rumour has it that Boeing are looking at using reverse thrust (737NG) for backing out of airbridge positions rather than using tugs to push back. The cost savings is significant by eliminating need for tug drivers (saving in union driven high salaries, overtime, and other workers benefits) Single engine reverse is being considered to save fuel but the extra thrust means higher fuel consumption so at this stage two engine reverse appears the go. One company is known to be looking into the possibility of employing deaf and dumb marshallers or wing tip walkers during the push back process. This offers considerable savings on radio headsets now used during push back. Sign language manuals will be issued to flight crew.

Amazing what operational measures can be taken to contribute to the financial health of the airline - something we all need to ensure we have a job...


Rumor has it that Elvis And M. Jacson is training for a big comebac, on the moon !
Rumor has it that we're gonna have to carry around on a big electrical engine and alot of batteries for pushback and taxi.
Rumor also has it that sone day some stupid engineer is gonna design the pilot out of the cockpit.
Relax, it's all rumors.

[BOAC]

I do hope A37575 didn't remove any scalp as he went over.

[rjay259]

Bullwinkle,

Do the ground staff at your airport approach an aircraft with the beacon still flashing?

Have to say at LGW they dont, but then again some of them do seem to be autonomous beings that must follow the strict rules as per the union. They buggers never come near us until we turn off the beacon, until it comes to loading and they do know best for the NG.

That said we SETI with the engine that will be on the inside of the final turn to stand, off. Our analysts have said that even two min with one engine can save 70-100 kgs. the 'added' extra power seems to generally be a non-event, unless we have to stop then its a pain in the ar5e.

259:cool:

[FCS Explorer]

Our analysts have said that even two min with one engine can save 70-100 kgs. the 'added' extra power seems to generally be a non-event

erm....come on! that would mean ONE eng uses 35kg/min during idle taxing.... kinda unlikely when u know that TWO eng INFLIGHT use 40/min...:ugh:

[BOAC]

5kg/minute/engine as a 'ball park'.

[HAWK21M]

Powerbacking on the B737 will have a cost on the Engine life too.Unless GSE not available then only use powerback on a B737...and remember to stop using FWD THRUST ONLY NOT the brakes.
regds
MEL.