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A Question About Diversions  
User currently offlineozark1 From United States of America, joined Mar 2006, 513 posts, RR: 1
Posted (3 years 6 months 4 weeks 1 day 23 hours ago) and read 3267 times:

Today in DFW AA has begun diverting some flights---currently 3 to ABI, 1 to AMA and 1 to ELP, but I am sure the list will grow as it did the other day.
Here's my question and i apologize if this topic has been discussed before and if so, if you could refer me to that thread I would appreciate it.
I understand the need for airlines to carry less fuel and consume less fuel. But does the cost of having to land in Abilene, pay a landing fee, fuel the airplane, and takeoff again for DFW, not equate to adding fuel at the departure city? , giving the flight some time to hold if needed when reaching the DFW area?. For instance, one of the diversons was from DEN to ABI and now waiting to complete the journey to DFW. That flight was not of excessive duration, yet had to divert. One day I worked a trip from OMA to DFW and we diverted to GGG. A woman in M/C was on the phone with AA res and they said the airport was open--so she was miffed why we had to divert. The captain, who was no charm boy, said we were diverting because we did not have enough fuel, period. So, we held on the ground for about an hour, fueled, and then took off for what ended up being a sunny landing in DFW.
How much authority do pilots have in the amount of fuel they can carry? Do company dispatchers decide the fuel amount and is that an amount set in stone by the airline? Are these policies the same at all airlines? I am only privvy to the list of diversions at AA but was just curious if WN had the same policy and the others as well.
Thank you for your time!!!

15 replies: All unread, jump to last
 
User currently offlineunattendedbag From United States of America, joined Oct 2003, 2337 posts, RR: 1
Reply 1, posted (3 years 6 months 4 weeks 1 day 22 hours ago) and read 3218 times:

Quoting ozark1 (Thread starter):
But does the cost of having to land in Abilene, pay a landing fee, fuel the airplane, and takeoff again for DFW, not equate to adding fuel at the departure city?

Pilots do look at the weather and they do add extra fuel at the origin. However, they do not fill the tanks to bursting just so they can hold for 2 hours in the air. In some cases, it is cheaper to divert, get some gas and depart.

[Edited 2011-05-01 16:35:34]


Slower traffic, keep right
User currently offlineAA737-823 From United States of America, joined Mar 2000, 5913 posts, RR: 11
Reply 2, posted (3 years 6 months 4 weeks 1 day 19 hours ago) and read 3135 times:

You also must remember that the diversion is often unrelated to fuel.
The air above DFW can only hold so many airplanes, and with many hundreds (thousands) of flights in and out of DFW daily, ATC eventually must send planes to alternates.
Further, when runway restrictions go into effect, and DFW gets down to just a fraction of the runways they'd normally use, you also run into the same problem. ATC will send the birds to wherever for a certain period of time, then clear them to continue.

They may/probably will refuel while on the ground, but that's to maintain minimums, etc.


User currently offlineGoldenshield From United States of America, joined Jan 2001, 6101 posts, RR: 14
Reply 3, posted (3 years 6 months 4 weeks 1 day 12 hours ago) and read 3066 times:

Quoting ozark1 (Thread starter):
How much authority do pilots have in the amount of fuel they can carry? Do company dispatchers decide the fuel amount and is that an amount set in stone by the airline?

Pilots have the authority to add as much fuel as within reason---even with fuel conservation. Of course, fuel loads ARE monitored by the airline beancounters, and thus it's not unheard of for pilots to get called to the carpet when their additions don't jive.

As for us dispatchers, we set the MINIMUM fuel to be carried for a flight; it's not set in stone, and as I mentioned above, the PIC can add more.

Quoting AA737-823 (Reply 2):
The air above DFW can only hold so many airplanes, and with many hundreds (thousands) of flights in and out of DFW daily, ATC eventually must send planes to alternates.

ATC does no such thing. They have no authority to. The decision of diversion rests squarely between the PIC and dispatcher, and even then, the PIC has final say (emergency authority of the dispatcher non-withstanding.)



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User currently offlineLAXintl From United States of America, joined May 2000, 26025 posts, RR: 50
Reply 4, posted (3 years 6 months 4 weeks 1 day 5 hours ago) and read 2989 times:

Even with the best planning, and best crew resource management, unplanned diversion will occur.

The diversion risk on a severe clear VFR day is still more than zero, while the risk during IFR conditions can never be completely eliminated either.

This is not to be considered a “failure”, but rather an acceptable risk. To mitigate the risk, airlines list alternate airports, to have the option to utilize them.

Anyhow, sometimes things can fall apart fast. From weather, to ATC, to a plane getting stuck on the runway which force a quick decision such as diverting.



From the desert to the sea, to all of Southern California
User currently offlinedxing From , joined Dec 1969, posts, RR:
Reply 5, posted (3 years 6 months 4 weeks 23 hours ago) and read 2880 times:

Quoting ozark1 (Thread starter):
For instance, one of the diversons was from DEN to ABI and now waiting to complete the journey to DFW. That flight was not of excessive duration, yet had to divert.

There were some big thunderstorms between DEN and DFW earlier today. ZFW and DFW tracon were having difficulty keeping the west and north arrival gates open for business. Don't know the size of the aircraft or the payload but if it was up against max payload, landing weight may have become an issue but that's a guess. You have to be reasonable in fueling an aircraft out of Denver. It's cool today but you can easily over-gross an aircraft for take off on a warm day. Sometimes you can plan for hold, and still have to divert due to rerouting in the air, aircraft holding, and weather en-route.

Quoting ozark1 (Thread starter):
One day I worked a trip from OMA to DFW and we diverted to GGG. A woman in M/C was on the phone with AA res and they said the airport was open--so she was miffed why we had to divert. The captain, who was no charm boy, said we were diverting because we did not have enough fuel, period. So, we held on the ground for about an hour, fueled, and then took off for what ended up being a sunny landing in DFW.

Like today, if there were big thunderstorms between departure and destination cities it doesn't matter if DFW wasn't actually getting hammered. I know gate agents that have taken to posting satellite pictures on the gate podium of weather delayed flights with big circles around the weather en-route and a note saying "The weather is HERE" as they are fielding numerous questions from passengers saying that the folks at the destination say it's a sunny day, no weather here and they are looking out the terminal windows at nice weather as well.

Quoting ozark1 (Thread starter):
How much authority do pilots have in the amount of fuel they can carry? Do company dispatchers decide the fuel amount and is that an amount set in stone by the airline?

Between the dispatcher and the pilot the most conservative plan wins out. If a pilot wants to take a bunch more fuel than I think is necessary and refuses to leave without it, if it isn't bumping payload I'll put in the slip and document it in my shift log. Usually though we are able to come to a mutual agreement that satisfies everyone.

Quoting AA737-823 (Reply 2):
ATC eventually must send planes to alternates.

No they don't. They will let an aircraft turn circles in the sky all day long if that is what the pilot wants to do. I remember hearing a story about one pilot that saw he was going to go into holding so he just requested his own reroute out a hundred miles and back again, by the time he got back, holding was gone and in he went.

[Edited 2011-05-02 15:40:25]

User currently offlineokie From United States of America, joined Jul 2003, 3149 posts, RR: 3
Reply 6, posted (3 years 6 months 4 weeks 20 hours ago) and read 2837 times:

Quoting dxing (Reply 5):
Between the dispatcher and the pilot the most conservative plan wins out. If a pilot wants to take a bunch more fuel than I think is necessary and refuses to leave without it, if it isn't bumping payload I'll put in the slip and document it in my shift log. Usually though we are able to come to a mutual agreement that satisfies everyone.


While I am hope that much data goes into the dispatchers estimate, I get the perception from your comments that unless the pilot comes and bargains/begs for fuel and just blindly accepts the dispatchers estimate that he is going to have to declare a fuel emergency, land under FAA minimums or divert.

Okie


User currently offlinebond007 From United States of America, joined Mar 2005, 5434 posts, RR: 8
Reply 7, posted (3 years 6 months 4 weeks 20 hours ago) and read 2827 times:

Quoting Goldenshield (Reply 3):
ATC does no such thing. They have no authority to. The decision of diversion rests squarely between the PIC and dispatcher, and even then, the PIC has final say (emergency authority of the dispatcher non-withstanding.)

If the airspace is saturated and filled to capacity, then the center will simply not accept any more aircraft. Unless it's a safety or emergency situation, then the pilot will follow ATC instructions. If ATC decides that due to volume, the pilot do a 180, then that's what the pilot will do.

Of course under normal circumstances, ATC will not tell an aircraft where to divert to, and common sense prevails, but, pilots will obey ATC instructions unless in an emergency. When in controlled airspace, the PIC and dispatcher only have the final say AFTER that of ATC.


Jimbo



I'd rather be on the ground wishing I was in the air, than in the air wishing I was on the ground!
User currently offlineGoldenshield From United States of America, joined Jan 2001, 6101 posts, RR: 14
Reply 8, posted (3 years 6 months 4 weeks 11 hours ago) and read 2726 times:

Quoting bond007 (Reply 7):
If the airspace is saturated and filled to capacity, then the center will simply not accept any more aircraft. Unless it's a safety or emergency situation, then the pilot will follow ATC instructions. If ATC decides that due to volume, the pilot do a 180, then that's what the pilot will do.

Of course under normal circumstances, ATC will not tell an aircraft where to divert to, and common sense prevails, but, pilots will obey ATC instructions unless in an emergency. When in controlled airspace, the PIC and dispatcher only have the final say AFTER that of ATC.

First off, don't confuse the issue. ATC has to one mission, and that's to keep things orderly, and safe. All ATC clearance have some reason behind them; however, if it doesn't make sense, then the pilot---and occasionally the dispatcher---has EVERY right to refuse it. Also, ATC have no right to deny a pilot of where he wants to go. If there's a hurricane blowing down south, and an airport isn't NOTAMed closed, then they have no right to deny him his request to go there. Conversely, in keeping with the discussion of this thread, if there's a line to get somewhere, and a crew decides to divert there, then that aircraft is thrown to the back of the line; however, again, it all deals with orderliness, and pilots and dispatchers are WELL aware of this.

From what I take of your post, what you are describing is an ORDER, of which, if the pilot doesn't act immediately, then there's going to be raining metal. Otherwise, everything else is for orderliness, and pilots and dispatchers are WELL aware of this.

Anyhow, I think you took my post out of context as a reply to the first part of what I quoted, and not the second, which is understandable given that I was trying to keep the context of the quoted sentence.

[Edited 2011-05-03 02:52:23]


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User currently offlineblueflyer From United States of America, joined Jan 2006, 4121 posts, RR: 2
Reply 9, posted (3 years 6 months 4 weeks 11 hours ago) and read 2717 times:
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Quoting dxing (Reply 5):
he just requested his own reroute out a hundred miles and back again

Why in the world would he want to do that? Didn't feel like looking down at the same corn fields for 30 minutes? Seriously, is there any reason to reroute over holding?



I've got $h*t to do
User currently offlineAAR90 From United States of America, joined Jan 2000, 3481 posts, RR: 46
Reply 10, posted (3 years 6 months 4 weeks 5 hours ago) and read 2629 times:

Quoting ozark1 (Thread starter):
I understand the need for airlines to carry less fuel and consume less fuel. But does the cost of having to land in Abilene, pay a landing fee, fuel the airplane, and takeoff again for DFW, not equate to adding fuel at the departure city? , giving the flight some time to hold if needed when reaching the DFW area?.

The answer is both "yes" and "no."

Yes - the cost of a single divert is greater than the cost for that single aircraft to carry extra fuel to avoid that divert.

No - the AVERAGE cost to carry extra fuel is much greater than the AVERAGE cost for the AVERAGE number of diverts due to not having "extra" fuel. This easily adds up to the tens of thousands of dollars every day.

Bottom line is that not every flight will be delayed and so there is a balancing act going on trying to find the right amount of "extra" fuel to put on each flight so as to minimize cost while maximizing probability of not diverting. In my experience the vast vast majority of the time any "extra" fuel is never used.... the expected delay simply doesn't occur.

FWIW, AA flight planning software utilizes historical data that includes the (weighted) AVERAGE delay a particular flight has encountered in the past and automatically adds HOLD FUEL to the flight plan to account for that dealy.



*NO CARRIER* -- A Naval Aviator's worst nightmare!
User currently offlinedxing From , joined Dec 1969, posts, RR:
Reply 11, posted (3 years 6 months 4 weeks ago) and read 2558 times:

Quoting bond007 (Reply 7):
When in controlled airspace, the PIC and dispatcher only have the final say AFTER that of ATC.

That is not entirely true. A pilot may always refuse a reroute if he does not have the fuel to accept the reroute. I wish more of them would. A pilot that declares an emergency is going to go where he wants and ATC will just have to make room for him. Just a couple of examples.

Quoting blueflyer (Reply 9):
Why in the world would he want to do that? Didn't feel like looking down at the same corn fields for 30 minutes? Seriously, is there any reason to reroute over holding?

Whether he burns the fuel turning circles or flying two straight lines does it make a difference?


User currently offlinebond007 From United States of America, joined Mar 2005, 5434 posts, RR: 8
Reply 12, posted (3 years 6 months 3 weeks 6 days 22 hours ago) and read 2536 times:

Quoting dxing (Reply 11):
That is not entirely true. A pilot may always refuse a reroute if he does not have the fuel to accept the reroute. I wish more of them would. A pilot that declares an emergency is going to go where he wants and ATC will just have to make room for him. Just a couple of examples.

Right, which is why I said:

Quoting bond007 (Reply 7):
Unless it's a safety or emergency situation, then the pilot will follow ATC instructions

Jimbo



I'd rather be on the ground wishing I was in the air, than in the air wishing I was on the ground!
User currently offlineblueflyer From United States of America, joined Jan 2006, 4121 posts, RR: 2
Reply 13, posted (3 years 6 months 3 weeks 6 days 13 hours ago) and read 2473 times:
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Quoting dxing (Reply 11):
Whether he burns the fuel turning circles or flying two straight lines does it make a difference?

For him maybe not, but isn't it easier for ATCOs to keep an eye on a plane circling at a holding point than going about somewhere and back? It's with that (sub)question in mind that I wonder whether there would be a good reason to increase ATC's workload.



I've got $h*t to do
User currently offlinebond007 From United States of America, joined Mar 2005, 5434 posts, RR: 8
Reply 14, posted (3 years 6 months 3 weeks 6 days 8 hours ago) and read 2436 times:

Quoting dxing (Reply 11):
Whether he burns the fuel turning circles or flying two straight lines does it make a difference?

Well, I can think of a few. Of course,we don't know the exact circumstances, and I'm sure he had a good reason for doing so ... it wasn't that he just 'wanted to do it'.

Firstly, by flying a 180, 100 miles from where he could have been holding, he is now completely out of the sequence. He might have been cleared before the ATC expected hold time, and now he's possibly 100 miles further from where he could have been ... and has to burn another 100 miles of fuel to get back there.

Secondly, when he turns back he is now out of sequence with perhaps several aircraft 'ahead' of him. ATC now has make an exception for him, if they allow him to keep his original sequence (personally I wouldn't - he'd be at the back of the line).

Also, depending on how many miles his reroute is, it may affect his ability to get to his alternate. Obviously 100 miles is not a big deal, but presumably calculations were made for standard holding. Obviously the reroute was discussed/approved by the dispatcher also, no probaby not an issue.

But again, we don't know why he chose to do it, so who knows!

Jimbo



I'd rather be on the ground wishing I was in the air, than in the air wishing I was on the ground!
User currently offlineYYZatcboy From Canada, joined Apr 2005, 1090 posts, RR: 0
Reply 15, posted (3 years 6 months 3 weeks 4 days 23 hours ago) and read 2306 times:
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Keep in mind as well that Dispatchers are just as if not more aware of the weather/ATC situation that the pilots are, and we don't just send flights out with minimum fuel if the conditions warrant extra fuel. But on a screaming clear VFR day all along the route, don't expect us to give an extra 45 minutes of fuel on top of the reserve fuel and all the other fuel we calculate.

At my airline we throw any added fuel that we think they may need in as tanker fuel, but if we absolutly want them to carry it we will put it in as contingency or holding fuel so that it is included in the MIN BRF number and the pilots cannot legally depart without it. (they can depart without the tanker fuel if they want to, which is the difference)



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