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Plane Answers: Why can't airlines wait at the gate vs. in a queue on the taxiway?
Mike asks:
Hello Kent,
There are times when I find myself on a plane that is waiting in the queue to depart and I wonder if this makes sense. After all, having 10 airplanes push from gates only to idle their engines for 20-30 minutes waiting to take off does not seem to be a good idea for an industry where fuel is the largest single cost.
Can you explain who decides when an aircraft pushes back and queues up to take off? Is there a reason that airplanes get in line to depart as opposed to just being assigned a number and waiting at the gate until it's their turn (other than if the gate is needed for an arriving plane)?
It doesn't really make sense, Mike. But some airports have adopted a gate hold program that does just what you're talking about; hold airplanes at the gate until the line begins to clear out. London and Paris both use this technique. However, even after holding at the gate for 15 minutes to an hour, we still often find ourselves waiting in line for departure as we approach the runway. It's simply a matter of the required spacing for departures combined with the number of flights scheduled to leave at the peak times that causes this.
There is also a concern by ATC that there may be no aircraft ready at the end of the runway for departure if they're held at the gate at the last minute, which would result in even more inefficiency.
Other airports (especially in the U.S.) will advise flights of a 'wheels up' time, allowing the pilots to push back at their discretion as long as they can be ready by the time given by ATC. This works to some extent, but flight crews are paid only after they push back from the gate, so the incentive to begin taxiing early is something that admittedly factors into their decision.
To prevent this, our company has a system in place to start the pay clock for pilots and flight attendants once an ATC delay is given which, in theory, would eliminate this incentive. In practice, many pilots don't trust the system to log the time or have been denied the extra pay in the past and would rather take the delay off the gate - possibly to an area where ATC will allow them to shut down the engines.
Richard Branson at Virgin made an attempt to think outside the box and looked into a tug system that could tow the airplanes to the end of the runway. Such a system could have saved hundreds of pounds of fuel per flight. Unfortunately, it was discovered that the extra wear and tear on the nose wheel would cost more than the savings generated by the reduced fuel burn.
Do you have a question about something related to the pointy end of an airplane? Ask Kent and maybe he'll use it for next Monday's Plane Answers. Check out his other blog, Cockpit Chronicles and travel along with him at work.
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Reader Comments (Page 1 of 1)
Former spatcher... Oct 24th 2009 3:17PM
I think the real answer is missed here. The cost of fuel and crew expense is directly borne by the airline operator. Increases in both of these areas are then reflected in higher costs and subsequently higher fares. The real culprit (at least in the U.S.) is our ATC system. There is no incentive for the ATC system to be efficient, and therefore it often is not. Individual controllers may attempt to be efficient, but often they are constrained by the bureacratic system in which they work. Whether the controller has the traffic in his/her control seperated by five miles or twenty-five miles, he/she gets paid the same. So, often they do less than the optimum, resulting in a snowball effect on the efficiency of the system. I commend the people who work in this environment that strive for excellence, and I wish there was a real way to compensate them for their efforts. Unfortunately, no such system exists.
The queuing system for departing flights would work if it was properly administered, but the ATC folks state they do not have the manpower to make it work. This attitude may be reality, but then we need to work to change this reality.
I have to chuckle about the "Airline Passenger Bill of Rights". All this will do is mess up an already fouled-up system by making hard rules where flexibility should live. I wonder if the DOT will then institute the "Bus Riders Bill of Rights", for those of us who commute and get stuck in traffic. If I'm late for work, do I sue the bus operator for damages?
jack Oct 5th 2009 6:46PM
Another reason for getting away from their gate is that the airline can claim to have left on time. The fact that the airplane has to wait inline for take-off does not count.
Gary Oct 5th 2009 7:52PM
On time statistics are logged regarding on time arrivals, not departures. So, if they flight leaves the gate on time and then sits in queue for 30 minutes, it most likely will arrive late and that is counted as a late flight.
Paul Davis Oct 6th 2009 1:32PM
Why did the flight crew unions ever agree to not getting paid until you push back from the gate? You all should get paid from the time you hit the doors at the airport. Or better yet a straight salary. Then it wouldn't matter when you pushed off.
Jeff Patterson Oct 12th 2009 4:37PM
For the same reason that the railroad unions negotiated these type of agreements: it's a great way to milk some good hourly pay. On the railroad it's not call pushback time. It's initial terminal time. They get a certain rate for mileage, per 100 miles.if you get delayed before you get outside agreement limits ( which can be 5 miles or more ) you go on hourly pay and you might sit hours waiting for a highball. We always prayed for snowstorms or delays to hold us up and make that extra cash.