Delta Back Taxi Causes Traffic Jam at ATL--Comments?

[Art at ISP]

I was subject to a very wierd delay this evening trying to get out of ATL. As we were taxiing out to 27R, a DL 767-300 taxied eastbound down the runway toward the end. Once reaching the end, he was unable to turn around due either to taxiway congestion or bad positioning. It took about 45 minutes to resolve the issue (some aircraft accepted intersection departures), and they had to bring out a tug to assist the aircraft. As a result I almost missed my connection in PHL.
I am just curious as to why ground or tower would allow a plane to back taxi on the active departure runway, and why he couldn''t have turned Right and departed from 27L (Assuming there is a taxiway between the 2 runways at the approach ends). This was a major bungle either by the pilot or ATC, and it was a new one to me.
Another question for those who might know ATL ATC patterns--would it not have made more sense for a northbound departure to PHL to depart from 26L on the north side of the airport instead of 27R on the south side? Both runways were active at the time...just a question for pondering.
Any educated replies are greatly appreciated.

 

[spinproof]

[P]Art[/P]
[P]You see you have the answer. Your questionwould it not have made more sense for a northbound departure... assumes the parties in question have some![/P]
[P]Spin[/P]
[P] [/P]
[P]Takeoffs are optional-landings mandatory[/P]

 

[JS]

I don't know why a 767 would taxi on the runway if the taxiway leading to the runway is full of aircraft waiting to depart. However, I can answer your other two questions.[BR][BR]As you can see from this ATL map:[BR][BR][A href=http://www.aopa.org/images/asf/taxi/00026AD.pdf]http://www.aopa.org/images/asf/taxi/00026AD.pdf[/A][BR][BR]27R extends beyond the end of 27L. If you're on 27R and pass taxiway N13, you're stuck on 27R.[BR][BR]There are more northbound departures from ATL than there are southbound. It would not make any sense to send every single northbound flight to runway 26L. The amount of time it takes to fly an extra 5000 feet is about 7 seconds.

 

[Chicken Taco]

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I don't know why a 767 would taxi on the runway if the taxiway leading to the runway is full of aircraft waiting to depart.
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Two good reasons:

1. Flow control time. If the 76 was going somewhere with ATC restricted flow control in effect (maybe BOS or NYC) he is issued a takeoff wheels-up time. If he cannot meet this time, it may be another hour or more to get a new release time. Therefore ATC may backtaxi one plane on the runway to get it out in advance of other planes that are in line.

2. Long-haul fuel considerations. When destination alternates and international reserves are figured in for a long flight, a plane reach its max fuel capacity or max weight with wery little extra fuel. In this case the 45 minutes of fuel burned taxiing (i'd guess 2500-3000 pph taxi burn) may take the plane below takeoff minimum fuel. ATC could expedite the plane to takeoff position using a backtaxi to allow the flight to bypass the long line and depart.

One more thing to consider is cockpit visibility. With the nose wheel 30 feet below and far behind the pilots, it's difficult to judge where the wheels are during a tight maneuver like a 180 degree turn. In order to pull this turn off, the crew would likely see nothing but grass out of the windows the whole time. The captain may have elected to stop out of a concern for safety, as an off-pavement excursion is not resume-enhancing

 

[airplt]

Atlanta has four east/west parallel runways. Two south of the terminal and two north of the terminal. They divide the departures. North and west departures go off the north side and south and east departures off the south side. A typical course flown from ATL to the northeast is approximalely 55 degrees. You are actually flying a little more east than north. There is not difference in time or distance by departing of the southside when heading to the northeast.