JETPILOT
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747 2 Engine Taxi

Sun Aug 30, 2009 8:27 am

Are there any operators taxiing to and from the runway on only 2 engines operating to save fuel?
 
unattendedbag
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RE: 747 2 Engine Taxi

Sun Aug 30, 2009 8:36 am



Quoting Jetpilot (Thread starter):
Are there any operators taxiing to

to the runway? no. It's the pilots responsibilty to ensure all systems, including the engines, are working properly before taxiing to the runway. Your senario would have the crew start the engines, check the systems and then shut 2 of them down for taxi. That wouldn't make much sense.

Quoting Jetpilot (Thread starter):
from the runway on only 2 engines operating

yes. to save fuel? It's the pilots decision and who knows what's going on in his/her head.
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JETPILOT
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RE: 747 2 Engine Taxi

Sun Aug 30, 2009 8:47 am

One of the companies I flew for allowed us to taxi to and from the runway with the center engine unpowered on the 727 at the captains discretion. If there was going to be a long taxi or there was a line for takeoff the #2 was started approx 5 minutes before taking the active.

Sounds like your speculating and really have no idea what your talking about. Am I correct?
 
unattendedbag
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RE: 747 2 Engine Taxi

Sun Aug 30, 2009 9:03 am



Quoting Jetpilot (Reply 2):
allowed us to taxi to and from the runway with the center engine unpowered on the 727 at the captains discretion.

Very similar aircraft. Im sure their type ratings are interchangeable...  Yeah sure

Quoting Jetpilot (Reply 2):
Sounds like your speculating and really have no idea what your talking about. Am I correct?

I have no earthly idea what I am talking about. That's why I spent a few minutes typing out a response to your question.
Slower traffic, keep right
 
JETPILOT
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RE: 747 2 Engine Taxi

Sun Aug 30, 2009 9:23 am

Many companies who fly twins taxi out on one engine. I think POLAR taxi's out their 747's on engines 1&4. I'm not sure and want to hear from someone who knows and is not taking a guess.

I'm not asking for a lesson on your perspective on FAR's which are incorrect. Thanks anyway.
 
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747classic
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RE: 747 2 Engine Taxi

Sun Aug 30, 2009 9:42 am

After landing when the engines are stabilized for 3 minutes (after reverse thrust) it was company policy on the 747 200/300 with KL and MP to shutdown one or two engines during taxi in.
It's always SCD (subject captain's decision) to shutdown the engines, depending on taxiway conditions, objects in engine blast area's and upcoming up-slopes (bridges) in the taxi in path and the actual landing weight.
In most cases engine no 3 was shutdown most of the time,. Shutdown of eng no 2 and 3 happened not very often. Special checklist items were added to allow for save taxi-in conditions (switching of hydraulic systems).On the 747-400 the procedure is still the same, I presume.

During taxi-out always all engines are started. However when it was very busy (very long taxi-out times, it was allowed to switch off engines and restart them to save fuel and to avoid a return to the gate and another fuel uplift.
Operating a twin over the ocean, you're always one engine failure from a total emergency.
 
theginge
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RE: 747 2 Engine Taxi

Sun Aug 30, 2009 10:58 am

If Engines are shut down on Taxi Out I believe that they have to be run for 5 mins before take off otherwise the engine could be damaged.
 
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747classic
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RE: 747 2 Engine Taxi

Sun Aug 30, 2009 11:54 am



Quoting 747classic (Reply 5):
If Engines are shut down on Taxi Out I believe that they have to be run for 5 mins before take off otherwise the engine could be damaged.

Yea, for thermal stabilization it 's necessary to idle the engines 5 minutes before T/O thrust is set.
During Taxi out (when standing in a long row for T/O) you can decide to shutdown one or two engines, however due the high break away thrust (to start the taxi out again) on the remaining engines (High TOW) this can be dangerous. In extreme cases (ORD) sometimes all engines were shutdown and restarted again to join the queue.
Operating a twin over the ocean, you're always one engine failure from a total emergency.
 
CosmicCruiser
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RE: 747 2 Engine Taxi

Sun Aug 30, 2009 3:43 pm



Quoting UnattendedBag (Reply 1):
It's the pilots responsibilty to ensure all systems, including the engines, are working properly before taxiing to the runway. Your senario would have the crew start the engines, check the systems and then shut 2 of them down for taxi. That wouldn't make much sense.

As others have said yes you can taxi out and in with an eng(s) shutdown. If the taxi out is long enough we delay start on #2 (MD-11). No configuration is done until all 3 are running. We found that even a fuel savings of a couple hundred lbs both in and out fleet wide saves millions in a yr. Definitely worth it but you must observe eng warmup and cool down limits.
 
Bellerophon
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RE: 747 2 Engine Taxi

Sun Aug 30, 2009 6:23 pm

Jetpilot

...Are there any operators taxiing to and from the runway on only 2 engines operating to save fuel?...

Yes.

BA has just completed a lengthy two-engined-taxy-out trial on its B747-400 fleet, conducted by instructor and management pilots, and will shortly make this procedure SOP for line crews, when conditions are suitable, in the near future.

There are many factors to be considered before deciding it is prudent to taxy a B747 out on only two engines, however Boeing has also researched the idea and published their conclusions in a technical study paper, and have no objection provided various conditions are met to this procedure.

BA's figures indicate a potential saving of around $1 Million - $2 Million per year.

As Theginge and B747classic and CosmicCruiser have all mentioned, diligently observing the engine warm-up period, prior to applying take-off power, is crucial if engine damage is to be avoided. It would probably only take one instance on a B747 to wipe out an entire year's fuel saving.

Best Regards

Bellerophon

[Edited 2009-08-30 11:28:15]
 
Sasha
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RE: 747 2 Engine Taxi

Tue Sep 01, 2009 1:07 am

As for POLAR, wouldn't taxiing on only 1-4 engines increase chance of FOD? Anyway, that's what would happen in our snowy airport, with narrow taxiways  Smile. Would the crew choose 1-4 over 2-3 for a particular reason? Or are engines used for taxi in rotation to evenly distribute "wear and tear", so to speak?

Thanks!
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lowrider
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RE: 747 2 Engine Taxi

Tue Sep 01, 2009 1:45 am

[

Quoting SashA (Reply 10):
Would the crew choose 1-4 over 2-3 for a particular reason? Or are engines used for taxi in rotation to evenly distribute "wear and tear", so to speak?

Hydraulic systems 1 and 4 power Nose gear steering, body gear steering, and brakes. All things I find desirable during taxi. You could taxi on just the inboards and still power these items using the demand pumps, but that leaves you with less redundancy. That is, however, what is done when there are notams for unexploded ordinance on the unpaved portions of the airport.
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chrisjw
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RE: 747 2 Engine Taxi

Tue Sep 01, 2009 2:18 am



Quoting Lowrider (Reply 11):
That is, however, what is done when there are notams for unexploded ordinance on the unpaved portions of the airport.

Uhhh, might be a bit off topic, but has that ever been of a concern in the United States? I could see where it might be possible in a conflict area (such as Baghdad). But unexploded ordinances near a taxiway at an airport located in the United States?
 
pilotpip
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RE: 747 2 Engine Taxi

Tue Sep 01, 2009 3:34 am

The outboard engines having a greater moment probably helps reduce breakaway thrust if the aircraft has to make a turn at low speed too.

No reason to have all four idling and burning fuel for 35 minutes waiting in line if you only need 5 minutes for everything to warm up. I don't know what ground idle is on a 747 but on the E-170 it's 500pph per side. I'd imagine the 747 is over 1000pph. If that's the case you'd save 150 gallons with a two engine taxi during that period. That adds up pretty quickly over a fleet of 20 aircraft that are doing this once or twice per day each.
DMI
 
HaveBlue
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RE: 747 2 Engine Taxi

Tue Sep 01, 2009 4:29 am



Quoting UnattendedBag (Reply 3):
I have no earthly idea what I am talking about.

Exactly!  Wink

Anyhow my friend flies the 747-200 and -300 for Southern Air and they do occassionally shut down an engine or two when taxiing and much less frequency when taxiing out, and it is engines 2 and/or 3 that get shut down as 1 & 4 are needed for hydraulics. One thing he mentioned that I haven't seen posted above is that one reason the Captain may elect to shut down an engine or two is because on the ships with PW engines, which were a little more powerful, even at idle you'd have to ride the brakes and on long taxis such as at ORD that could be a big problem. Cut an engine or two and less heat and stress on the brakes.
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747classic
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RE: 747 2 Engine Taxi

Tue Sep 01, 2009 6:27 am

Quoting HaveBlue (Reply 14):
Anyhow my friend flies the 747-200 and -300 for Southern Air

Slightly of topic :
Could you ask your friend with Southern Air, what the total hours/cycles count is for the two ex. KLM aircraft he is flying. Registrations N748SA and N746SA, probably the 747's with the most flying hours, see thread "Highest Number Of Flying Hours" on the civil aviation forum.

Quoting HaveBlue (Reply 14):
One thing he mentioned that I haven't seen posted above is that one reason the Captain may elect to shut down an engine or two is because on the ships with PW engines, which were a little more powerful, even at idle you'd have to ride the brakes and on long taxis such as at ORD that could be a big problem. Cut an engine or two and less heat and stress on the brakes.

This is correct for taxi in. It prevents "riding the brakes" for the PW-powered aircraft, with an higher idle thrust setting. CF6 engines have a lower idle thrust setting and don't have this problem.
During taxi out idle power of four (4) PW engines is however not sufficient to taxi due the far higher T/O weights.

[Edited 2009-08-31 23:34:37]

[Edited 2009-09-01 00:19:09]
Operating a twin over the ocean, you're always one engine failure from a total emergency.
 
JETPILOT
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RE: 747 2 Engine Taxi

Tue Sep 01, 2009 10:57 am

I imagine there will be 2 different checklists for a 2 engine taxi vs. 4. Can anyone provide me with checklists? Anything online maybe?
 
CosmicCruiser
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RE: 747 2 Engine Taxi

Tue Sep 01, 2009 12:21 pm



Quoting JETPILOT (Reply 16):
I imagine there will be 2 different checklists for a 2 engine taxi vs. 4. Can anyone provide me with checklists?

For us in the MD-11 (2 in lieu of 3) There is no separate chk list but there is a page in the QRH addressing considerations for a 2 eng taxi out/in and delayed eng start. The one big required procedure is that the jet cannot be configured nor the before T/O chklist be accomplished until all 3 are running. I'm not allowed to post such chklist.
 
lowrider
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RE: 747 2 Engine Taxi

Tue Sep 01, 2009 1:30 pm



Quoting Chrisjw (Reply 12):
but has that ever been of a concern in the United States? I could see where it might be possible in a conflict area (such as Baghdad). But unexploded ordinances near a taxiway at an airport located in the United States?

Not that I know of, but a lot of 747 flying happens outside the US.

Quoting JETPILOT (Reply 16):
I imagine there will be 2 different checklists for a 2 engine taxi vs. 4.

There is a Delayed Engine Start checklist that is run before after the After Start and before starting the remaining engines.
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CheetahC
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RE: 747 2 Engine Taxi

Tue Sep 01, 2009 8:36 pm

Quoting Lowrider (Reply 11):
Hydraulic systems 1 and 4 power Nose gear steering, body gear steering, and brakes. All things I find desirable during taxi. You could taxi on just the inboards and still power these items using the demand pumps, but that leaves you with less redundancy.

Wasn't taxiing on engines 2&3 a contributory factor to the Saudi Arabian 747 that went into the ditch in Malaysia?


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[Edited 2009-09-01 14:00:15]
 
lowrider
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RE: 747 2 Engine Taxi

Tue Sep 01, 2009 10:58 pm



Quoting Cheetahc (Reply 19):
Wasn't taxiing on engines 2&3 a contributory factor to the Saudi Arabian 747 that went into the ditch in Malaysia?

I don't have that one in my files, but that is certainly plausible.
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HaveBlue
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RE: 747 2 Engine Taxi

Wed Sep 02, 2009 3:06 am



Quoting 747classic (Reply 15):
Could you ask your friend with Southern Air, what the total hours/cycles count is for the two ex. KLM aircraft he is flying. Registrations N748SA and N746SA, probably the 747's with the most flying hours

He said one is the highest time, and one is the most cycles of any classic in the world... but he's not sure which one is which. He flew 746SA last week, a military related run out of the states. 746 leaves JFK tomorrow for a round the world trip with stops in Dover, DE and Hong Kong among others, arriving back at JFK on the 7th. He said 746 was in the desert, and that they brought it back. 748 he isn't sure about it but on his company tracking it isn't listed as online atm.

Hope that helps.  Smile
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747classic
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RE: 747 2 Engine Taxi

Wed Sep 02, 2009 5:55 am



Quoting HaveBlue (Reply 21):
He said one is the highest time, and one is the most cycles of any classic in the world

Thanks for the cooperation. If possible I would like to have the actual hours/cycles.
I am planning to write a book about all KL and MP registered 747 classics.
Sorry guys a little off topic
Operating a twin over the ocean, you're always one engine failure from a total emergency.
 
HaveBlue
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RE: 747 2 Engine Taxi

Wed Sep 02, 2009 4:17 pm



Quoting 747classic (Reply 22):
Thanks for the cooperation. If possible I would like to have the actual hours/cycles.
I am planning to write a book about all KL and MP registered 747 classics.
Sorry guys a little off topic

I will ask him to do what he can to find out.  Smile
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jetmech
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RE: 747 2 Engine Taxi

Thu Sep 03, 2009 2:42 am



Quoting Cheetahc (Reply 19):
Wasn't taxiing on engines 2&3 a contributory factor to the Saudi Arabian 747 that went into the ditch in Malaysia?

I can't find the official report, but if this was the case – and assuming hydraulic systems #1 and #4 where not pressurised by the ADP's (or ACMP's ?) - it is possible that taxing on #2 and #3 alone contributed to the accident.

Nose gear and body gear steering are powered by hydraulic system #1, with primary brakes powered by hydraulic system #4. Hydraulic systems #1 and #2 act as first and second alternate brakes respectively.

Thus, if hydraulic systems #1 and #4 were not pressurised, the only function that would have been of any use for taxying would have been second alternate brakes.

Regards, JetMech
JetMech split the back of his pants. He can feel the wind in his hair :shock: .
 
wwward3
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RE: 747 2 Engine Taxi

Fri Sep 04, 2009 8:50 am

A maintenance taxi can always be different from one time to the next. For example a canceled flight will leave you with a lot fuel on board, that requires more brake away thrust. A lot of times leaving the gate area there are a lot of ground equipment and ground workers. If this is the case you might want to use 4 engines for your brake away and once rolling shut down 2 & 3 for two reasons, one saves fuel and the other is once rolling with 4 engines running you will need constant braking. Each situation can be different.
 
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747classic
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RE: 747 2 Engine Taxi

Fri Sep 04, 2009 11:31 am

On the following link, something is mentioned about this incident :
http://aviation-safety.net/database/record.php?id=20010823-0

"The Boeing 747 rolled into a drainage ditch and toppled forward causing the severe damage to the nose section. The aircraft was taxied to the departure gate to board 319 passengers for Jeddah, Saudi Arabia. Reportedly, the aircraft was being taxied by a ground engineer on the no. 2 and 3 engines. When trying to make a turn brakes and steering had no effect and the aircraft continued into the ditch. It is said that the aux hydraulic pumps switches were in the off position."

I have the following question :
- Is it normal that an aircraft moves under his own power, with a ground engineer at the controls?
In the companies were I was employed, this was strictly prohibited, Minimum crew to taxi was one (of course qualified )pilot and F/E. (747-200/300)
All taxi movements to and from the hangar were performed by a tow truck and one Qualified person at the controls (brake pedals) and hydraulic systems 1 & 4 pressurized, with no gear pins installed. ( according a special checklist)
All engine runs, performed by ground crew, are with parking brakes set and wheels blocked.
Operating a twin over the ocean, you're always one engine failure from a total emergency.
 
sfotom
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RE: 747 2 Engine Taxi

Fri Sep 04, 2009 10:43 pm

Yes, our flight crews now normally start and taxi away from the terminal on only 1 & 4, starting 2 & 3 when closer to takeoff.

As qualified to taxi 747-400 for maintenance, our procedures are to taxi on only 2 engines (1 & 4) unless circumstances require otherwise. Hydraulics are supplied for 2 & 3 by pneumatic driven pumps. (although 2 & 3 are not really required for maintenance taxi, steering comes off 1 & 4 only, and braking uses system 4 first, and automatically shifts to system 1 if pressure on 4 is lost. System 2 will then back up system 1 on the brakes but for system 2 to be your only break source you would need to loose hydraulic systems 4, 1, and the brake accumulator.
 
HaveBlue
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RE: 747 2 Engine Taxi

Fri Sep 04, 2009 11:51 pm

Interesting post sfotom, and welcome to Airliners.net!  Smile
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JETPILOT
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RE: 747 2 Engine Taxi

Sat Sep 05, 2009 6:03 am

Thanks for sharing this information gentlemen. I only wish i could get a hold of a delayed start checklist.

I also read that TWA was doing 2 engine start and taxi back in 1996.
 
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747classic
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RE: 747 2 Engine Taxi

Sat Sep 05, 2009 6:38 am



Quoting Sfotom (Reply 27):
As qualified to taxi 747-400 for maintenance

Just interested, did you receive special taxi training in a full flight simulator (with motion )?
Taxiing in a 747 is very special, due the high position of the cockpit, ahead of the nose wheel. Sharp corners must be practiced very well, because the downward outside vision is somewhat impaired on this aircraft type ( row 3 of the business/first class compartment is right below the pilot cockpit seats). The cockpit sits on top of the aircraft.
Operating a twin over the ocean, you're always one engine failure from a total emergency.
 
unattendedbag
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RE: 747 2 Engine Taxi

Sat Sep 05, 2009 9:59 am

Quoting Sfotom (Reply 27):
As qualified to taxi 747-400 for maintenance, our procedures are to taxi on only 2 engines (1 & 4) unless circumstances require otherwise.

There's a difference in required engine power between taxiing a fully laden 747 carrying gas, passengers/cargo and taxiing a relatively empty 747 for maintenance repositioning or run-up.

Is this policy for both maintenance flight crews and passenger flight crews?

[Edited 2009-09-05 03:05:55]
Slower traffic, keep right
 
sfotom
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RE: 747 2 Engine Taxi

Sun Sep 06, 2009 12:37 am



Quoting HaveBlue (Reply 28):
Interesting post sfotom, and welcome to Airliners.net! Smile

Thank You. I've lurked for many years and decided it was time to come on board.

Quoting 747classic (Reply 30):
Just interested, did you receive special taxi training in a full flight simulator (with motion )?

Yes. The training to become qualified to taxi as maintenance for us includes classroom, full motion simulator (the same sims the pilots use) and a checkout in a live aircraft. (the sim training is excellent, but for the feel of actually driving one, the sim is just not enough by itself.)

Quoting UnattendedBag (Reply 31):
There's a difference in required engine power between taxiing a fully laden 747 carrying gas, passengers/cargo and taxiing a relatively empty 747 for maintenance repositioning or run-up.

Is this policy for both maintenance flight crews and passenger flight crews?

There certainly is a difference, a light 747 with all 4 at idle on a level ramp will move off all by itself and will require regular brake applications to keep speed under control, at full weight with a slope to the ramp and all 4 running you might need to be near safe thrust limits just to get the aircraft moving.

The procedures for flight and maintenance are written differently, but in both cases aircraft and field conditions are to be taken into consideration in the decision as to taxi on 2 or 4 engines. In any case, I am aware of outbound international flights starting 2 engines at the terminal, and only starting the remaining 2 as they approached the runway.
 
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747classic
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RE: 747 2 Engine Taxi

Sun Sep 06, 2009 6:28 am



Quoting Sfotom (Reply 32):
I've lurked for many years and decided it was time to come on board.

Welcome to Airliners.net.

Quoting Sfotom (Reply 32):
Yes. The training to become qualified to taxi as maintenance for us includes classroom, full motion simulator (the same sims the pilots use) and a checkout in a live aircraft. (the sim training is excellent, but for the feel of actually driving one, the sim is just not enough by itself.)

I can understand that ground crews are licensed to start engines and make an engine run (test run license). But why would an airline invest in taxiing on engine power to the hangar from the gate and back by ground crews. In most airports that's not allowed anyway, you have to be towed in and out. Besides it's not very cost efficient. (fuel burn and maintenance cost - one extra cycle on the engines - you have to mark fuel used in the AFL .) There are already some airports, that forbid you to start the APU during towing. And as you were saying your self : you need a lot of practice to learn the taxiing by actual doing it.

During my almost thirty years operating the 747 (classic) I noticed that taxiing was one of most challenging things new pilots on the 747 had to learn.
Operating a twin over the ocean, you're always one engine failure from a total emergency.
 
sfotom
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RE: 747 2 Engine Taxi

Mon Sep 07, 2009 6:22 am



Quoting 747classic (Reply 33):
I can understand that ground crews are licensed to start engines and make an engine run (test run license). But why would an airline invest in taxiing on engine power to the hangar from the gate and back by ground crews. In most airports that's not allowed anyway, you have to be towed in and out. Besides it's not very cost efficient.

Some countries do not allow a non-pilot to move an aircraft under it's own power (taxi). In the US that is not the case, in fact at some airports towing from maintenance areas to the terminal is not allowed unless a high speed tug is available because it is to slow and causes too much congestion on the taxiways. In a lot of locations if an aircraft is taken out of service with an engine problem and needs to be run at high power at a remote locatin to either trouble shoot, or confirm that the problem is fixed, the local allotment of tugs are in full use at the terminal.
 
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747classic
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RE: 747 2 Engine Taxi

Mon Sep 07, 2009 7:22 am



Quoting Sfotom (Reply 34):
Some countries do not allow a non-pilot to move an aircraft under it's own power (taxi). In the US that is not the case, in fact at some airports towing from maintenance areas to the terminal is not allowed unless a high speed tug is available because it is to slow and causes too much congestion on the taxiways

IMHO you need a lot of experience to taxi a 747, especially if you taxiing with two or three engines operating, because special system-settings are in force then. A lot of airlines allow only the captain to taxi the aircraft.
In aviation still the following rule is valid : SAFETY FIRST, NOT ECONOMICS.
If I was in charge in your company I would buy(or hire) a high speed tow truck, allocated especially for maintenance movements. The investment can be earned back easily by fuel and engine maintenance savings and than I don't even speak about environmental issues.

By the way : Are you allowed to taxi more aircraft types, than only the 747 ?
Operating a twin over the ocean, you're always one engine failure from a total emergency.
 
sfotom
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RE: 747 2 Engine Taxi

Tue Sep 08, 2009 4:28 am



Quoting 747classic (Reply 35):
IMHO you need a lot of experience to taxi a 747, especially if you taxiing with two or three engines operating, because special system-settings are in force then. A lot of airlines allow only the captain to taxi the aircraft.
In aviation still the following rule is valid : SAFETY FIRST, NOT ECONOMICS.
If I was in charge in your company I would buy(or hire) a high speed tow truck, allocated especially for maintenance movements. The investment can be earned back easily by fuel and engine maintenance savings and than I don't even speak about environmental issues.

By the way : Are you allowed to taxi more aircraft types, than only the 747 ?

Airliners I've taxied over the years include, the 727, 737-200/300, 747-100/200/SP/400, 757, 767, 777-200, DC 10, A 319/320 and BAC-111.

Airliners I've been qualified to run but not taxi include DC 8, A 300 and L1011.

In addition I hold a commercial pilot certificate with multi-engine and instrument ratings and have flown (and taxied) numerous general aviation aircraft.

The airline equipment that I've worked with are from a career that has spread over 4 different airlines and over 34 years. Granted, the taxi qualification process at some of those airlines was not as extensive as I felt that they should be, but the airline I'm with now has an extensive program to qualify for run/taxi including prerequisites, classroom and practical training, written and practical exams, and medical examination. Once qualified there are currency requirements, annual proficiency exams, and medical exams to stay qualified. There are mechanics that taxi that I consider just as competent, professional and safe, to operate an aircraft on the ground as any pilot.

Now I could go on for a long time on shortcomings that I feel exist in airline management, and government aviation organizations in regards to the safety vs economics issue, but I don't agree with you on this one. I will acknowledge that the issue of fuel cost and environmental footprint are not the same as they were 30 years ago and that today any ground operation, whether by mechanic, or pilot is being scrutinized. There are some advocating that aircraft should be towed from the gate to the end of the runway for departures, but I haven't seen a successful application of this idea yet.

By the way, one of the nice things about transitioning to the 747-400 from the 747 classic is that there are no special system-settings for taxiing on 2 engines. All 4 demand pumps (the old ADPs) are in auto already. Brake system transfer is fully automatic. With no galleys operating, electrical loads for maintenance taxi with only 2 generators is not a concern (and if there was a problem, load shed and recovery is automatic)
 
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747classic
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RE: 747 2 Engine Taxi

Tue Sep 08, 2009 8:18 am



Quoting Sfotom (Reply 36):
There are mechanics that taxi that I consider just as competent, professional and safe, to operate an aircraft on the ground as any pilot

I don't mean it personally , but I disagree in this respect.
Seen, what your qualifications are, you are not the average ground mechanic/ engineer. I also noticed that you are an instructor and multi-engined qualified as a pilot.
However, the average proficiency level of most ground crew is IMHO far less.
The problem is that ground crews have more type ratings. So, if I understand you correctly, you are allowed to taxi the 747-400 and some other types at the same time.(not all you have listed, I hope)
I was allowed (retired now ) only one type rating at one time, to preclude type related failures. (wrong switching, when thinking you are in a different aircraft type).

Quoting Sfotom (Reply 36):
By the way, one of the nice things about transitioning to the 747-400 from the 747 classic is that there are no special system-settings for taxiing on 2 engines. All 4 demand pumps (the old ADPs) are in auto already. Brake system transfer is fully automatic. With no galleys operating, electrical loads for maintenance taxi with only 2 generators is not a concern (and if there was a problem, load shed and recovery is automatic

It's nice : But, don't count to much on automatics, if it fails your back on your self again.

Quoting Sfotom (Reply 36):
There are some advocating that aircraft should be towed from the gate to the end of the runway for departures, but I haven't seen a successful application of this idea yet.

I agree with you.
However, I still cannot see why taxiing to and from hangars, engine run-up areas ,etc is done by actually taxi the aircraft in the present day.
Operating a twin over the ocean, you're always one engine failure from a total emergency.
 
HaveBlue
Posts: 2104
Joined: Fri Jan 30, 2004 3:01 pm

RE: 747 2 Engine Taxi

Mon Sep 21, 2009 8:22 pm

I was in Charlotte, NC yesterday on my way from Boston to Daytona Beach. (USAirways Flight 1761 connecting to 2441). While eating at the lone Sbarros with a window facing the ramp I watched as an ERJ 170 (N116HQ) was pushed back, started the #2 engine only and taxiied out. Thought of this thread as I watched it and just thought it was interesting that I got to see that, as I don't fly commercially very often and when I do I rarely am in a position to get a chance to see the airliner from dead in front and watch them do the pushback/startup.
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