Towing Aircraft to the Runways?

Question

I work for a company that does MX on Commerical aircraft, and I wonder if the aircraft were TOWED to the active runway (actually stopping short before being allowed on the runway) and then start the engines. They can power up electronics and Air/Con with on board power, then do the start up just before they go onto the active runway. all pre-flight checks are done, would this not save a tremendous amount of fuel, or am I wrong on this?

Answer 1

One of the major problems with moving large aircraft with tugs, at anything other than SLOW speed, is the possible damage to the landing gear, which is what the tugs hook to.

Answer 2

(a) Flying an aircraft is done following a set of procedures and checks. The tug driver and pilot minds are different as their responsibilities are different. The pilot follows the lines and markings depending on the ATC clearance to take-off from any particular runway.

(b) Further, the landing & take-off depends on operation planning and it will be an awful job for the tug driver to go to runway-2 if the ATC doesn't allows the aircraft to take-off from runway-1. Similarly for landing.

(c) Thirdly, you will require more tug drivers than the aircrafts, for an airport where more than 50 flights take-off or a similar no. of  flights land, like JFK for example. It will be a headache.

Answer 3

Sir Richard Branson is attempting to do this with all Virgin Flights.  Whether or not it saves enough money and emissions to make a difference is hard to say.  Tugs are expensive and use fuel as well.  From an air traffic control standpoint, who is the ground controller talking to?  Do they talk to the crew or the tug driver.  It would make sense to talk to the crew because they have all the training, but then if the instructions change there will be a lag when the crew has to contact the tug driver.  Then you have all these tugs running around on the taxiways and runways that can easily get in the way and could cause a runway incursion.  So if the tug drivers need taxi instructions back to the gates after dropping an aircraft off at the runway, you just doubled the controller workload.  Interesting concept but I don't think it is practical.  Replace jet fuel with bio fuels and then we would have something that would save money and emmisions.

Answer 4

It would not really save that much aircraft fuel, and would waste a tremendous amount of time, both for the aircraft and the maintenance personnel involved.

Answer 5

Having had to train people to tow aircraft, several thousand hours of my own time on a tow tractor, that's not the best idea in the world.

Theoretically, you'd put more vehicles on the active taxiways and runways. These would need clearance from ground controllers to return to the parking area. (I had to bake a batch of cookies to thank the controllers for being patient with us when we had part of our ramp shut down.)

Tow vehicles don't move quickly either. Picking one of the easiest; if I tow a 737 to the hold short line, I have to A) disconnect the towbar, B) head up the runway until the closest taxiway, C) be in continual contact with ground controllers until I'm back on an uncontrolled ramp, D) be as familliar with the airport and capable of radio usage as airline pilots themselves. E) Dodge every other aircraft on the taxiway.

It amounts to a lot of work, a lot of trust, and to face the facts, most line rats probably shouldn't be trusted with anything sharper than a ballpoint pen. I had to go retrieve one dunce, whom I'd shown how to get around the runway, and decided to cross the runway anyway without clearance when the controllers were threatening to have him arrested.

I also have to ask the question of what to do if there's a malfunction at engine start up. A tractor has to be sent back to the aircraft with a towbar, connect to the aircraft, and move it out of the hold short area, again in continual contact with ATC and ground controllers. Even with preflight inspections complete, I've seen some brilliant s***w ups discovered on the ramp at engine start that probably shouldn't be handled at the hold short line by a line rat in a hurry. (Does this take ETO 2380 or Mobil Jet II? Are the hydraulics 5606 or Skydrol?)

Arguably, it might save a tremendous amount of oil. Even if I assume that all the airlines went to purely electric pushbacks, it comes at the cost of electricity and with more usage of coal or more nuclear waste.

The decreased safety, greater probability of runway incursions, distraction of ATC doesn't justify the savings that would be made in fuel by having the aircraft towed to the hammerhead.

JT

Answer 6

Makes no sense. You see the airlines are reeeeeaaaal good at figuring out how to make money with airplanes. If their not already doing it ....................

Answer 7

This is one of the proposals to save fuel that many people champion.

It is limited by a few factors.  

1) Its a very slow process to tow an aircraft.  It slows the operation of the airport down dramatically to do these types of things.  

2) aircraft moving around under the power of people other than the pilots tends to make those pilots nervous.  While many tug drivers are aware of the legalities of moving planes around an active airport, the pilot in command is still the authority as to its safe conduct, so any mistake that is made is defacto the fault of the pilot.  That tends to make them a bit leery.

3)That would take a lot of tugs and a lot of drivers.  This would be a significant expense that would have to be passed on to the customers.  While it may save actual fuel, the amount of extra labor costs associated with it mean it does not save much money, and therefore is not a particularly attractive option.

Answer 8

First of all... the taxi uses 1-5 gallons of fuel which boeings use 1-5 gallons every 30 seconds in the air.

Answer 9

We actually did this as a test at my airline. The tractor picked up the nose wheel of the 747, and could tow one at speeds up to 35 MPH. We started the engines enroute to the runway so the checks would all be completed on arrival and we could immediately take off. Saved about $5500 per flight. Pretty good, but the tug cost over $1M, and could only handle one jet at a time.

Answer 10

It would save on fuel, but it is not allowed under normal circumstances.  It probably wouldn't waste any time, as aircraft are pushed back with tugs all the time and can be towed as fast as they can be taxied under normal circumstances.

But in order to get an IFR clearance, the plane must be running (otherwise if an engine doesn't start or some other system isn't working, it screws up the whole system).  For this reason planes will call clearance delivery 'ready to start' so they burn the minimum fuel required.  Long takeoff cues can't be avoided at busy airports, but planes still use less fuel per person than many cars.

Edit:

For all those naysayers that say towing is more dangerous and slower you've got to be kidding!  A spotter on the tug has a full view of the aircraft as it is moving (unlike the pilots) and is far more maneuverable.  You can't back up as safely taxiing the plane as towing it.  It takes a whole 30 seconds to hookup or release the tow bar under the worst conditions and even with all of the aircraft power off there is still enough accumulator pressure for the aircraft brakes to help stop the plane in an emergency.  

I've put large jet aircraft into hangars with inches to spare around tail docks and roof trusses; I could tow a plane down a 100 foot wide taxiway with a centerline in my sleep.

Answer 11

and what if something malfunctions between the time that they're at the runway, boot everything up and then have to get towed back to the gate because of the malfunctioning equipment (which could possibly be an engine)? then what are they gonna do. it would just cause further delays because the aircraft would just have to get towed right back to the gate, which takes time.

good idea, but not practical.

Answer 12

No Captain in her right mind would consider surrendering responsibility for her airplane on the taxiways to a tug driver!

It's been tried a couple of times, but it's very costly, introduces new risks to the airplane, and generally creates more legal complications than it's worth.

Answer 13

I've heard of this being done for a ferry flight of a 747, but I think that under normal circumstances the logistics of towing aircraft to and from runways makes doing so impractical, despite the potential fuel savings.  Also, some checks have to be done after engine start, so if the engines are started right at the hold point before turning onto the runway, the checks are going to take more time.