ehho
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Taxi Or Tow From Gate To Runway?

Fri Jul 27, 2007 11:48 pm

An article appeared on the Dutch news site NOS.nl today, citing a request by the Dutch socialist party to require AMS ops to have aircraft towed to the gate from the runway and vice versa, claiming that this will seriously diminish noise hazard and air pollution. The article goes on to say that "British research shows that at airports like SFO and LHR, towing can save up to 3% in fuel use". The source implies that savings can be made at AMS as well, "given its relatively large size". It also claims that Dutch authorities have already looked into this 12 years ago, but that "the industry says that benefit to the environment wouldn't be very big".

Full article in Dutch.

I wonder, does towing between gate and runway occur anywhere in the world as SOP? Is it even theoretically viable. given cost and maintenance of extra tow trucks? Will it really save fuel, given that the tow truck also needs quite a lot?

Any comments welcome, wonder if this is really smart or just another bureaucratic idiocy, or maybe something in between.
"Get your facts first. Then you may distort them as much as you please" -- Mark Twain
 
DIA
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RE: Taxi Or Tow From Gate To Runway?

Fri Jul 27, 2007 11:59 pm

I think it is SOP here and there in the world...I remembered one...from the caption of the photo here, "After some maintenance with ATC Lasham Ltd, G-ZAPU is seen here being towed onto runway 06 for a departure to Stansted. It is standard practice at Southend to tow 757's onto 06 due to the tight taxiway. It has been known that the odd aircraft of this size to get stuck in the mud when lining up under its own power!"


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Photo © Simon Nicholls - London Aviation Photography

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joemonster
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RE: Taxi Or Tow From Gate To Runway?

Sat Jul 28, 2007 12:09 am

From what I remember there was a thread on this before about Virgin using this idea at LHR. I'm not sure if it was just a discussion about the merits of it or if it was actually implemented for a trial period.
I do remember though that concerns were raised about if the engines didn't start at the designated 'holding bay' and having to get it back to the terminal. Also it was mentioned that aircraft might not have their engines run/warmed up enough before they got to the runway and so could cause safety issues.
I can't find the actual thread but this one comments on the original one i mentioned Movement Impact Due To Virgin Fuel Saving Trials? (by EK413 Jan 11 2007 in Civil Aviation)
 
kappel
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RE: Taxi Or Tow From Gate To Runway?

Sat Jul 28, 2007 12:21 am

Quoting Joemonster (Reply 2):
From what I remember there was a thread on this before about Virgin using this idea at LHR. I'm not sure if it was just a discussion about the merits of it or if it was actually implemented for a trial period.
I do remember though that concerns were raised about if the engines didn't start at the designated 'holding bay' and having to get it back to the terminal. Also it was mentioned that aircraft might not have their engines run/warmed up enough before they got to the runway and so could cause safety issues.

Correct. It's one of the ideas of the suddenly green Virgin boss, SRB. Well, he said it anyway, I'm not sure if it's his idea. But I think the idea has merit. I know the Dutch like to be a pioneer in trying new things (always have been), so I wouldn't be surprised if it happens. Wuold be a nice precedent as AMS is one of the world's biggest airports (even though they dropped out of the top 10 this year)

Quoting EHHO (Thread starter):
Will it really save fuel, given that the tow truck also needs quite a lot?

Yes, but not nearly as much as an aircraft. This idea would have even more merit in congested airports like JFK, where aircraft have to wait in line to take-off for a while.
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greggarious
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RE: Taxi Or Tow From Gate To Runway?

Sat Jul 28, 2007 1:01 am

A few questions regarding the subject:

While fuel costs would be lessened by pulling aircraft to the runway, what about time? If, for example, there was a distance of a couple of miles from the gate to the runway, how quickly could a tug pull an aircraft across said distance? Is there a significant decrease in taxiing speed compared to an aircraft moving under its own power. If there is, I get the impression that towing aircraft might increase congestion on the taxiways at large airports, when interspersed with arriving aircraft taxiing to the gate on their own (as I doubt there would be a fleet of tugs waiting at the end of the runways).

Moreover, how many tugs does a large airport have at its disposal? I'm not well versed in ramp operations, but I wonder about the new logistical issues that would arise from the implementation of this concept. If a tug had to pull an aircraft a couple of miles from gate to runway (a defenite possibility at large airports such as AMS), could it make the round trip back to the gate in enough time so that other aircraft would not have to wait unnecessarily in order to be coupled and pushed back? Would there be enough equipment on hand in order to cover the tugs in transit (so to speak)?
 
deltaffindfw
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RE: Taxi Or Tow From Gate To Runway?

Sat Jul 28, 2007 1:40 am

Delta is working on a solution. It would be awesome if it works!

GIBRALTAR, March 29, 2007 – WheelTug plc and Delta Air Lines entered into an agreement in which the airline will assist WheelTug in developing a new system that has the potential to enable pilots to back away from gates without a tow tug, and taxi to and from takeoff and landing points without using jet engines. The new WheelTug™ system aims to reduce fuel consumption, noise and emissions in airport terminal areas and taxiways, as well as reduce airport and gate congestion that can lead to reduced ground equipment delays.

Full development and approval of the system is expected sometime in 2009 and Delta, as WheelTug’s launch customer, could begin installing the system on its fleet of B-737NG aircraft as early as late 2009. The WheelTug system includes powerful electric motors in the airplane's nose wheel that will enable pilots to back away from gates without a tow tug and then taxi to their takeoff, or a remote start point before starting the airplane's engines. After landing, the pilot can turn off the jet engines and use the system to drive the airplane to its gate.

http://news.delta.com/article_display.cfm?article_id=10647
 
cloudyapple
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RE: Taxi Or Tow From Gate To Runway?

Sat Jul 28, 2007 1:49 am

Let's start with a start up coordinator at EVERY american airport. Instead of starting the engines and entering the departure queue at number 58, wasting fuel and pumping fumes into the atmosphere, let the start up coordinator assign a push back slot. This will save more fuel than the combined effect of doing anything elsewhere.
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dl767captain
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RE: Taxi Or Tow From Gate To Runway?

Sat Jul 28, 2007 3:52 am

seems like a good idea to me if it saves fuel and probably a lot easier for pilots since they can do other things while being towed and could probably go faster also
 
LHRBlueSkies
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RE: Taxi Or Tow From Gate To Runway?

Sat Jul 28, 2007 4:41 am

I'm in 2 minds about this subject....

On the one hand, anything that helps to save fuel (therefore the environment), reduce noise and improve safety must be a good thing.

On the other hand, at the moment, I doubt companies motives (especially Bransons - Mr Publicity!), and that the safety aspects have been suitably looked into to ensure an appropriate long-term solution.

What happens when the APU breaks, or the a/c can't start an engine at the threshold? More inconvenience to tow it back to a gate to get fixed, delaying how many other carriers along the way?

And as Greggarious rightly said, how many tugs must an airport have to cover this operation? And what if the Wheeltug fails at the wrong location, blocking the runway, etc?

Too many what if's for this to go ahead fully yet... more trials and options are needed.
flying is the safest form of transport - until humans get involved!
 
DIA
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RE: Taxi Or Tow From Gate To Runway?

Sat Jul 28, 2007 4:52 am

Quoting DL767captain (Reply 7):
seems like a good idea to me if it saves fuel and probably a lot easier for pilots since they can do other things while being towed and could probably go faster also

On the other side of the coin...

I wonder if the airlines, FAA, insurance companies, etc. have any input here...I seriously doubt all parties would have no problem with "tow-drivers" stepping up their responsibilities (especially at busy airports)...pulling around these multi-ton fuel wagons (with pax) behind them...among many others around them. I can see the whole thing turning sour very quickly at the first "wrong-turn" or "wing-clipping" that occurs. Can we actually employ 1000s of these "tow-drivers" and have them understand how to communicate with ground/tower, and pilots at the same time and accurately?

I'll tell you one thing, if all this is eventually approved...they better prepare to pay much higher wages to the "tow-drivers" that is for sure.
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pilotpip
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RE: Taxi Or Tow From Gate To Runway?

Sat Jul 28, 2007 4:54 am

Towing to the runway will have no positive effects. However let's think of the negatives.

1: Safety- I can think of a number of issues here alone. Tugs and towbars running around will result in the need for extra lanes of travel. From an aircraft standpoint, most engines require the engines running for a certain amount of time before temperatures are safe for flight.

2: Costs- You need at least two extra crewmembers for each tow crew. You need a tug for each aircraft. You need diesel or gasoline for each of these tugs which also makes me question the environmental bennefit. Single engine taxis don't burn a huge amount of fuel after an initial burst of breakaway thrust. I have a had time believing that a Diesel engined tug burns less fuel than a turbine at idle using maybe 200pph (equal to about 12 gallons per hour). An APU will use even less than this and still provide enough for the packs if you're sitting for an extended time.

3: Time constraints- believe it or not, most airports don't have an issue with delays on a normal day. However due to too many flights trying to get on the same strip of land at the same time this only works during good weather. I'm not taking off in a thunderstorm as a pilot, and when I worked ramp I would not have been out there working a flight in that weather.
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vv701
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RE: Taxi Or Tow From Gate To Runway?

Sat Jul 28, 2007 8:54 am

Quoting Joemonster (Reply 2):
From what I remember there was a thread on this before about Virgin using this idea at LHR. I'm not sure if it was just a discussion about the merits of it or if it was actually implemented for a trial period.

VS issued a press release last December saying that they would be "carrying out test trials throughout DEcember" on their "starting grid" programme that involved towing their aircraft from the terminal stands to the holding area at runway thresholds. This press release can be found at:
http://www.virgin-atlantic.com/en/gb...e/pressreleases/news/pr041206c.jsp

Since that date there has, as far as I know, been no more information released. However on the VS site there is a page on the airlines's environmental policies and practices. Here is a link:
http://www.virgin-atlantic.com/en/gb...aboutus/environment/ouractions.jsp
This says "In addition to our starting grid initiative . . ." with a link to the press release detailed above. This environment page does not comment further as to whether the "starting grid" trials were actually carried out or what the assessments revealed if they were carried out.

As these trials were to be concluded more that 6 months ago . . . Perhaps someone out there knows if the trials were made and, if so, what they revealed? Or was this simply another publicity stunt?
 
Shenzhen
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RE: Taxi Or Tow From Gate To Runway?

Sat Jul 28, 2007 9:48 am

Quoting Pilotpip (Reply 10):
1: Safety- I can think of a number of issues here alone. Tugs and towbars running around will result in the need for extra lanes of travel. From an aircraft standpoint, most engines require the engines running for a certain amount of time before temperatures are safe for flight.

I would certainly hate to be on an airplane that has the nose gear steering bypassed for tow, running down the runway before there is enough air movement over the control surfaces...

Cheers
 
Aleksandar
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RE: Taxi Or Tow From Gate To Runway?

Sat Jul 28, 2007 11:10 am

Well, that solution developed by Delta seems interesting, I'm really looking forward to learning more about it.

As for towing planes from gates to runways, it might work well only for smaller airports. I doubt it would work well in those mega huns such as FRA, LHR, CDG. Situation there is already chaotic and the last thing they need on aprons and taxiways are additional tow tractors.
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Philadelphia1
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RE: Taxi Or Tow From Gate To Runway?

Sat Jul 28, 2007 1:47 pm

Ive got it. Solar powered tow trucks.  Smile

Saves fuel for the airlines right?

LHR may have difficulty with that as the sun is not as abundant as say LAX
 
ckfred
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RE: Taxi Or Tow From Gate To Runway?

Sat Jul 28, 2007 3:48 pm

I have to say that the more vehicles moving around at an airport, the more likely there will be an accident.

I was on an AA flight from ORD to ATL. We taxied to the gate about 15 minutes ahead of schedule, and the ground crew was no where to be found, so the captain shut down the engines and called for the tug, rather than burn jet fuel at high prices waiting to be marshalled into the parking spot.

After we had just started into the gate, there was a thud, and the plane came to an abrupt stop. The tug hit a catering truck. Apparently, the driver of the truck thought the tug was pushing back the plane and parked, and the tug driver and crew members didn't notice the truck parked over the lead-in line.

A friend of mine is a 757/767 F/O with AA. Once, while taxiing in at ORD, a catering truck drove around an MD-80 that was having its tug unhooked, and straight into the path of my friend's 757. Just as my friend thought that either there was going to be an accident, or the captain might stand on the brakes and send the F/As and every loose item flying,

The captain called for the landing lights. That got the truck driver's attention, and he promptly slammed on his brakes.

My point is that there are enough hazards just around airport concourses with the many ground vehicles that tow airplanes, move baggage, fuel planes, and cater planes. If tugs start towing planes to and from gates, there are going to be tugs crossing active runways or trying to pull a plane out of a hold pad and past other parked planes. All of these situations have the potential for serious consequences.
 
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ADent
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RE: Taxi Or Tow From Gate To Runway?

Sat Jul 28, 2007 4:22 pm

It is an OK idea. I don't think idling/taxiing jets make that much noise (compared to Takeoff/Landing).


Boeing said it was OK to tow their jets, but in the long term the front landing gear wasn't designed to be towed that far that often and it would wear quicker.

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