|Quoting Ultrapig (Reply 5):|
Followup question-Understood that gate usuage is very important. But at what point would it make sense for airlines and airports consider equiping "bullpen" areas with hook up so planes could be towed there and parked whiled hooked up waiitng for deaprture with no engine running.
An let's say on a 737-700 for example how much is the fuel flow with the engines just idling compared to crusing?
Can a plane in a very long line sut of one engine during the wait ala the taxiing to gate procedure?
The problem with the power idea is now you have to staff this remote area as well as equipping it. I don't see that as a viable option.
The penalty box at ORD
gets used a lot. Single engine taxi is not only encouraged, but it's SOP for us. Of course, there's the stipulation of abnormal situations which still gives the captain authority to fire up both. We have to let the engines run for at least two minutes after landing for cooldown. My normal flow for things is to shut down #2 when the captain prompts me (or I ask) and fire up the APU as we get about 5 gates away from ours. If we end up going to the box, my job is to start coordinating. I get on with ops, find out how long it's going to be. If it's going to be quite a while the captain may elect to fire up the APU and shut down the engines (I'll get to that in a minute) becuase the APU burns much less fuel. Once in the box, we usually wait for ramp or ops to call and tell us the gate is open. If it's been a while, I make a note of what gate we're going to and try to listen for it. If we have the engines shut down we'll fire one up and when the other aircraft calls for push. By the time they call for taxi we're ready to go and all is well.
Some rough fuel figures for the ERJ-170
Engines Idle- 550pph (per engine)
Cruise 1800-2000pph (per engine)
Breakaway thrust 800-1000pph (single engine)
APU 175 pph
As you can see, it's to our advantage to go single engine or even APU when we're sitting for a while. Better yet, I'd much rather use the GPU and ground air but at some stations (IAD
) you're going to have a hard time talking the ramp into hooking up the A/C. This time of year if they don't hook it up, we're leaving the APU running because at some point passenger comfort becomes a bigger issue than fuel savings.