Scheduled departure prior to scheduled arrival?
Jun 14, 2016, 8:31 am
#1
Original Poster
Join Date: Feb 2006
Programs: HH Silver, MR Plat Prem & LT Plat, Hyatt Plat,SPG Plat, Hertz PC, National EE, UA 1K
Posts: 3,405
Scheduled departure prior to scheduled arrival?
Not sure I quite understand why UA schedules flights like this:
6/14/16 DFW-DEN Departure 9:33am "delayed due to a late inbound aircraft arrival"
Hitting where is this aircraft coming from:
DEN-DFW "Inflight - Estimated to arrive 3 minutes early". Scheduled 7:00am departure, arrival 9:52am
I am not an airline scheduler, but how do you get a departure time 19 minutes before the arrival? Isnt my time valuable?
6/14/16 DFW-DEN Departure 9:33am "delayed due to a late inbound aircraft arrival"
Hitting where is this aircraft coming from:
DEN-DFW "Inflight - Estimated to arrive 3 minutes early". Scheduled 7:00am departure, arrival 9:52am
I am not an airline scheduler, but how do you get a departure time 19 minutes before the arrival? Isnt my time valuable?
Jun 14, 2016, 8:35 am
#2
Join Date: Dec 2010
Location: TX
Programs: UA 1K
Posts: 729
Most likely your flight was to be serviced by a different airplane that is even more delayed or has gone mechanical. They are subbing it out for this plane coming from DEN. UA has saved you time - perhaps many hours - preventing you from having to wait for that original plane.
Jun 14, 2016, 8:50 am
#3
Moderator: United Airlines
Join Date: Jun 2007
Location: SFO
Programs: UA Plat 1.995MM, Hyatt Discoverist, Marriott Plat/LT Gold, Hilton Silver, IHG Plat
Posts: 66,850
Jun 14, 2016, 8:50 am
#4
FlyerTalk Evangelist
Join Date: Aug 2015
Posts: 11,461
There was an equipment change for that flight last night, although I don't know the reason.
So it wasn't originally assigned to the aircraft now scheduled to arrive after the original stated departure time.
Code:
Jun 14 01:50 (UTC) Gate Adjustment AEQP Changed From 319 To 320 TAIL Changed From N826UA To N402UA
Jun 14, 2016, 8:55 am
#5
Join Date: Jan 2005
Location: New York, NY
Programs: UA, AA, DL, Hertz, Avis, National, Hyatt, Hilton, SPG, Marriott
Posts: 9,451
Friends often show me this scenario as an example of United's supposed incompetence, but scheduling is a difficult concept to explain to non-airline people. I am not sure of a more concise, articulate way to characterize this particular situation. Perhaps coding it as "aircraft change" might be more instructive.
This is an unintended consequence of United giving fairly detailed reasons for delays. The inbound airplane may be on time or early for that particular scheduled flight, but the forthcoming delay for the downline flight will be attributable to a "late turn" due to the aircraft swap.
With less information on the reason for delays, we'd see the inbound flight on time or early, yet after the scheduled departure time of the downline leg, and probably complain about United scheduling illogical turns!
This is an unintended consequence of United giving fairly detailed reasons for delays. The inbound airplane may be on time or early for that particular scheduled flight, but the forthcoming delay for the downline flight will be attributable to a "late turn" due to the aircraft swap.
With less information on the reason for delays, we'd see the inbound flight on time or early, yet after the scheduled departure time of the downline leg, and probably complain about United scheduling illogical turns!
Jun 14, 2016, 9:00 am
#6
Join Date: Aug 2010
Location: Morris County, NJ
Programs: UA 1K/*G, Avis Pres, Marriott Plat
Posts: 2,305
It's not that "where is this aircraft coming from?" returns bogus data - it's always accurate - but that the aircraft you're looking at may very well not be the one you're going to fly.
"Where is this aircraft coming from?" shows the status of the plane that's scheduled for your flight, as of this moment. United's network planners can (and do!) change that at any time. This is ESPECIALLY true in irrops situations, but can and does happen in the course of normal business.
So I guess I'm trying to say - the tool itself is actually quite reliable, but can't predict the future. It doesn't "know" that the network planners are going to swap out your plane for another one.
It's a great tool but in no way should be used for anything more than mild amusement.... doesn't always have bearing on reality.
Jun 14, 2016, 9:42 am
#7
Join Date: Apr 2005
Location: ORD
Programs: AA, UA Plat, HH Gold, Marriott Amb
Posts: 418
Yep, happened to me yesterday. Scheduling pulled our original plane, that was on time, and replaced it with another plane that was supposed to arrive early, but 20 minutes after our scheduled departure.
Didn't take the time to track the original tail number to see where it went.
Created cascading delays down the line for all the rest of the flights assigned to the original plane as well.
Didn't take the time to track the original tail number to see where it went.
Created cascading delays down the line for all the rest of the flights assigned to the original plane as well.
Jun 14, 2016, 9:44 am
#8
FlyerTalk Evangelist
Join Date: Mar 2010
Location: DAY
Programs: UA 1K 1MM; Marriott LT Titanium; Amex MR; Chase UR; Hertz PC; Global Entry
Posts: 10,159
"Where is this aircraft coming from" is much more useful outside of the United Hubs. I find it very useful when tracking my UAX planes coming into Dayton and being able to predict if there is going to be delays.
On the downside, with UAX the info flow is not always well coordinated, and delays are not reliably posted to the flight status even when delays are certain...and then they often just auto creep delays by 10 or 15 minutes.
On the downside, with UAX the info flow is not always well coordinated, and delays are not reliably posted to the flight status even when delays are certain...and then they often just auto creep delays by 10 or 15 minutes.
Jun 14, 2016, 9:57 am
#9
Join Date: Feb 2006
Programs: UA, Starwood, Priority Club, Hertz, Starbucks Gold Card
Posts: 3,952
Dispatch involves a much more complex set of circumstances than the simplistic thinking that the aircraft originally scheduled for the flight is and can be the only aircraft used for that flight. Substitutions happen.When I see an obvious disconnect between arrival aircraft info and expected departure time, I don't question the stupidity of the airline, but remind myself that I don't know about a lot of behind-the-scene things.
OTOH, on AA, often the app posts my flight as "on time" even though it's past departure time, I'm waiting at the gate with the other pax, and there is no plane in sight.
Jun 14, 2016, 10:05 am
#10
Moderator: Budget Travel forum & Credit Card Programs, FlyerTalk Evangelist
Join Date: Aug 2002
Location: YYJ/YVR and back on Van Isle ....... for now
Programs: UA lifetime MM / *A Gold
Posts: 14,428
Jun 14, 2016, 10:06 am
#11
Join Date: Jan 2008
Location: EAU
Programs: UA 1K, CO Plat, NW Plat, Marriott Premiere Plat, SPG Plat, Priority Gold, Hilton Gold
Posts: 4,712
Yeap, basic explanation:
App shows the status of the plane that is scheduled to operate your flight.
If that plane is going to be late, and operations intends to swap that plane for another one and still operate your flight on time, they won't adjust your flight times because they are, indeed, correct.
But if they don't know what plane they're going to put you on yet, they can't assign your flight to that plane, so you're stuck looking at the status of the plane previously assigned, even though that won't be your plane.
I suppose United could add an "unassigned" state where a scheduled flight doesn't have any plane assigned, but that would probably weird out passengers even more. "What do you mean there's no plane for this flight?"
App shows the status of the plane that is scheduled to operate your flight.
If that plane is going to be late, and operations intends to swap that plane for another one and still operate your flight on time, they won't adjust your flight times because they are, indeed, correct.
But if they don't know what plane they're going to put you on yet, they can't assign your flight to that plane, so you're stuck looking at the status of the plane previously assigned, even though that won't be your plane.
I suppose United could add an "unassigned" state where a scheduled flight doesn't have any plane assigned, but that would probably weird out passengers even more. "What do you mean there's no plane for this flight?"
Jun 14, 2016, 10:43 am
#12
Join Date: Feb 2002
Location: BNA
Programs: HH Gold. (Former) UA PP, DL PM, PC Plat
Posts: 8,184
As has been said, it's complicated.
Even on the front lines flying the airplanes most of what is going on behind the scenes is not always apparent. Each hub has an SOC with a dozen or two employees who are monitoring and working on these issues. It's quite impressive to see. There is far too much going on to include all that detail in a simple delay code.
I recently had an example of how they swap around resources to minimize the delays when the system is disrupted. I was flying from the west coast into IAH with a scheduled turn of nearly two hours to BNA. We received an ACARS message saying that we were being rescheduled to fly TPA instead of BNA due to the TPA crew misconnecting. The TPA flight was scheduled to depart only minutes after our IAH arrival so it ended up being delayed waiting for us. I found out later that the TPA crew had gotten caught up in a weather delay in DEN when storms stopped operations for some time. That crew had been rescheduled to our BNA overnight which departed later though they were so late that they delayed that flight as well though both flights were delayed much less than the TPA flight would have been delayed if they had kept us all on our original schedule. SOC traded two short delays (less than an hour each) for one very extensive delay (over four hours, IIRC).
The root cause of both delays was the weather in DEN even though the weather in IAH, TPA, and BNA was fine. So what should the app say for the reason for the delay? Awaiting Crew? Weather? Operational Difficulties? All of the above? I don't have the answer for that.
This swap was crewmembers, not airplanes, but it shows the type of thing that happens behind the scenes all the time to recover from system disruptions.
Even on the front lines flying the airplanes most of what is going on behind the scenes is not always apparent. Each hub has an SOC with a dozen or two employees who are monitoring and working on these issues. It's quite impressive to see. There is far too much going on to include all that detail in a simple delay code.
I recently had an example of how they swap around resources to minimize the delays when the system is disrupted. I was flying from the west coast into IAH with a scheduled turn of nearly two hours to BNA. We received an ACARS message saying that we were being rescheduled to fly TPA instead of BNA due to the TPA crew misconnecting. The TPA flight was scheduled to depart only minutes after our IAH arrival so it ended up being delayed waiting for us. I found out later that the TPA crew had gotten caught up in a weather delay in DEN when storms stopped operations for some time. That crew had been rescheduled to our BNA overnight which departed later though they were so late that they delayed that flight as well though both flights were delayed much less than the TPA flight would have been delayed if they had kept us all on our original schedule. SOC traded two short delays (less than an hour each) for one very extensive delay (over four hours, IIRC).
The root cause of both delays was the weather in DEN even though the weather in IAH, TPA, and BNA was fine. So what should the app say for the reason for the delay? Awaiting Crew? Weather? Operational Difficulties? All of the above? I don't have the answer for that.
This swap was crewmembers, not airplanes, but it shows the type of thing that happens behind the scenes all the time to recover from system disruptions.
Jun 14, 2016, 10:49 am
#13
Join Date: Jan 2016
Programs: UA 1K; *G, AA Plat
Posts: 1,700
Jun 14, 2016, 10:52 am
#14
FlyerTalk Evangelist
Join Date: Oct 2006
Location: SFO/SJC
Programs: UA Silver, Marriott Gold, Hilton Gold
Posts: 14,884
Flightstats shows this info if you go into the details. Free account needed, and don't think it shows the tail numbers specifically, but does show aircraft swaps, IIRC.
Jun 14, 2016, 10:53 am
#15
FlyerTalk Evangelist
Join Date: Mar 2010
Location: DAY
Programs: UA 1K 1MM; Marriott LT Titanium; Amex MR; Chase UR; Hertz PC; Global Entry
Posts: 10,159
As has been said, it's complicated.
Even on the front lines flying the airplanes most of what is going on behind the scenes is not always apparent. Each hub has an SOC with a dozen or two employees who are monitoring and working on these issues. It's quite impressive to see. There is far too much going on to include all that detail in a simple delay code.
I recently had an example of how they swap around resources to minimize the delays when the system is disrupted. I was flying from the west coast into IAH with a scheduled turn of nearly two hours to BNA. We received an ACARS message saying that we were being rescheduled to fly TPA instead of BNA due to the TPA crew misconnecting. The TPA flight was scheduled to depart only minutes after our IAH arrival so it ended up being delayed waiting for us. I found out later that the TPA crew had gotten caught up in a weather delay in DEN when storms stopped operations for some time. That crew had been rescheduled to our BNA overnight which departed later though they were so late that they delayed that flight as well though both flights were delayed much less than the TPA flight would have been delayed if they had kept us all on our original schedule. SOC traded two short delays (less than an hour each) for one very extensive delay (over four hours, IIRC).
The root cause of both delays was the weather in DEN even though the weather in IAH, TPA, and BNA was fine. So what should the app say for the reason for the delay? Awaiting Crew? Weather? Operational Difficulties? All of the above? I don't have the answer for that.
This swap was crewmembers, not airplanes, but it shows the type of thing that happens behind the scenes all the time to recover from system disruptions.
Even on the front lines flying the airplanes most of what is going on behind the scenes is not always apparent. Each hub has an SOC with a dozen or two employees who are monitoring and working on these issues. It's quite impressive to see. There is far too much going on to include all that detail in a simple delay code.
I recently had an example of how they swap around resources to minimize the delays when the system is disrupted. I was flying from the west coast into IAH with a scheduled turn of nearly two hours to BNA. We received an ACARS message saying that we were being rescheduled to fly TPA instead of BNA due to the TPA crew misconnecting. The TPA flight was scheduled to depart only minutes after our IAH arrival so it ended up being delayed waiting for us. I found out later that the TPA crew had gotten caught up in a weather delay in DEN when storms stopped operations for some time. That crew had been rescheduled to our BNA overnight which departed later though they were so late that they delayed that flight as well though both flights were delayed much less than the TPA flight would have been delayed if they had kept us all on our original schedule. SOC traded two short delays (less than an hour each) for one very extensive delay (over four hours, IIRC).
The root cause of both delays was the weather in DEN even though the weather in IAH, TPA, and BNA was fine. So what should the app say for the reason for the delay? Awaiting Crew? Weather? Operational Difficulties? All of the above? I don't have the answer for that.
This swap was crewmembers, not airplanes, but it shows the type of thing that happens behind the scenes all the time to recover from system disruptions.
Throw in all the crew member's schedule and legal-time availability...I am sure it gets complicated.