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LAX ATC - Back In Line.  
User currently offlineMauiman31 From United States of America, joined exactly 7 years ago today! , 450 posts, RR: 0
Posted (6 years 2 months 2 weeks 3 days 21 hours ago) and read 3643 times:
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Hey experts. . . tell me what happened. . . I was on AA #2300 yesterday 757-2 LAX to DFW. We were number one for take off after an on time push back. We sat there at the end of the runway and didn't go. Finally started to move again off the end of the runway. Captain came on pa -- said that ATC "asked us to get back in line to help with east bound traffic control". We went back to the taxi way sat as many others passed by. . . Captain came back on and said they had to readjust navigational ??? because when we got out of line it got messed up (paraphrasing of course - he was more articulate than that.) and it would take a few minutes. After about 20 minutes total we got back in line and took off. Have never had that happen. Was getting back in line for traffic control about the size and speed of our plane??

15 replies: All unread, jump to last
 
User currently offlineOPNLguy From , joined Dec 1969, posts, RR:
Reply 1, posted (6 years 2 months 2 weeks 3 days 21 hours ago) and read 3617 times:

They had a security breach yesterday by some nut claiming that he had a bomb. Nothing was allowed to leave until they had it mopped up and knew (possibly) how many other people may have been involved. Flights couldn't push or enter the gates, and things on the ground couldn't takeoff. Lasted about 2.5 hours... It may have taken 15-20 minutes for authorities to figure out if your flight was involved.

An alternative idea is that your 757 (which requires increased separation for a following aircraft) was re-sequenced to the end of the line to get other aircraft out strikes me as a liitle "unusual".

[Edited 2008-07-03 11:09:27]

User currently offlineMir From United States of America, joined Jan 2004, 21626 posts, RR: 55
Reply 2, posted (6 years 2 months 2 weeks 3 days 21 hours ago) and read 3610 times:

I can think of several reasons why this might have happened:

1) Flow restriction over your departing fix. If the TRACON or ZLA suddenly called and said they needed more in-trail spacing, you may have been put in the position of having to wait more for your takeoff time, which would have delayed the planes behind you.

1a) After waiting, the flight got a reroute (which would have required the crew putting the new route into the computer), and then had to wait for appropriate in-trail spacing over the new departure fix to be able to take off.

2) DFW went into a delay program, and the captain wasn't honest about it.

Those are the only things that come to mind - sounds pretty strange.

-Mir



7 billion, one nation, imagination...it's a beautiful day
User currently offlineDiscoverCSG From United States of America, joined Jan 2007, 832 posts, RR: 0
Reply 3, posted (6 years 2 months 2 weeks 3 days 21 hours ago) and read 3551 times:



Quoting Mauiman31 (Thread starter):
Captain came on pa -- said that ATC "asked us to get back in line to help with east bound traffic control".



Quoting Mir (Reply 2):
2) DFW went into a delay program, and the captain wasn't honest about it.

If DFW went into a GDP, how was the captain's explanation anything less than honest?


User currently offlineOPNLguy From , joined Dec 1969, posts, RR:
Reply 4, posted (6 years 2 months 2 weeks 3 days 20 hours ago) and read 3521 times:



Quoting DiscoverCSG (Reply 3):
If DFW went into a GDP, how was the captain's explanation anything less than honest?

I went back and looked at the ATCSCC messages, and didn't see any GDP for DFW...


User currently offlineDiscoverCSG From United States of America, joined Jan 2007, 832 posts, RR: 0
Reply 5, posted (6 years 2 months 2 weeks 3 days 20 hours ago) and read 3506 times:

Well, if it was about the security breach, and making sure this flight wasn't affected, I can understand why the captain didn't say so.

I mean, imagine the panic that could break out on an AA 752 if the captain said takeoff was being delayed because there might be a terrorist on board!


User currently offlineMir From United States of America, joined Jan 2004, 21626 posts, RR: 55
Reply 6, posted (6 years 2 months 2 weeks 3 days 20 hours ago) and read 3470 times:



Quoting DiscoverCSG (Reply 3):
If DFW went into a GDP, how was the captain's explanation anything less than honest?

He could have just said that DFW was delayed.

-Mir



7 billion, one nation, imagination...it's a beautiful day
User currently offlineMakeMinesLAX From United States of America, joined Dec 2003, 566 posts, RR: 0
Reply 7, posted (6 years 2 months 2 weeks 3 days 19 hours ago) and read 3410 times:

Slightly off-topic, but I learned something interesting by way of UA's channel 9 on a LAX-IAD flight a few weeks ago. Throughout the flight, the cockpit crew used the callsign "United 946 tango heavy". Upon landing, I asked the captain about the extra designation and he explained it was used to distinguish our flight from a similarly labelled one which was expected to be in the same airspace.

At first, I thought it only related to the flight number, in which case this would be a common occurrence and would entail a lot of research prior to every flight (i.e. looking up the same flight number for every airline across the flight path). It then occurred to me that the conflicting flight was the change-of-plane continuation of UA 946 from IAD to AMS. Our flight was delayed and UA obviously didn't plan to hold the other aircraft, so there was a likelihood of two United 946s in the IAD airspace simultaneously.


User currently offlineUalflyer From United States of America, joined Aug 2004, 58 posts, RR: 0
Reply 8, posted (6 years 2 months 2 weeks 3 days 11 hours ago) and read 3260 times:

I have been on the same United 946 many times, however, normally the call sign is United 8144, but that is an on-time departure.

User currently offlinePlatinumfoota From United States of America, joined Jan 2006, 556 posts, RR: 0
Reply 9, posted (6 years 2 months 2 weeks 3 days 10 hours ago) and read 3216 times:
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Quoting MakeMinesLAX (Reply 7):
Slightly off-topic, but I learned something interesting by way of UA's channel 9 on a LAX-IAD flight a few weeks ago. Throughout the flight, the cockpit crew used the callsign "United 946 tango heavy". Upon landing, I asked the captain about the extra designation and he explained it was used to distinguish our flight from a similarly labelled one which was expected to be in the same airspace.

At first, I thought it only related to the flight number, in which case this would be a common occurrence and would entail a lot of research prior to every flight (i.e. looking up the same flight number for every airline across the flight path). It then occurred to me that the conflicting flight was the change-of-plane continuation of UA 946 from IAD to AMS. Our flight was delayed and UA obviously didn't plan to hold the other aircraft, so there was a likelihood of two United 946s in the IAD airspace simultaneously.

Yes United uses this alot. For my flight they used the designation LIMA, got the same answer from the Captain.



Never forget United 93
User currently offlineEchster From United States of America, joined Sep 2004, 399 posts, RR: 0
Reply 10, posted (6 years 2 months 2 weeks 2 days 19 hours ago) and read 3068 times:

At about the time your flight was scheduled for departure a notice was sent out to ATC to call TMU for reroutes for aircraft over Gallup, New Mexico (GUP). Seems there were storms in the area with high tops and little offset space. This affected several of the aircraft I was working.

User currently offlineMcdu From United States of America, joined Apr 2005, 1466 posts, RR: 17
Reply 11, posted (6 years 2 months 2 weeks 2 days 18 hours ago) and read 3033 times:

Here is one thing that may have affected the navigation and required at least a 10 min reset. On our non-GPS equipped airplanes, when departing LAX on an RNAV SID we would have to do a quick alignment with the IRU's at the end of the runway to update the position of the airplane, the GPS airplanes don't need this extra step as they are always updating off the satellites. The catch is that if you move the airplane while in the quick align mode you lose the nav system and have to start over from scratch which takes about 10 minutes to align itself. No way to bypass the alignment process or expedite.

This is just speculation but it sounds reasonable after the Captains PA announcement.


User currently offlineSpeedbird128 From Pitcairn Islands, joined Oct 2003, 1648 posts, RR: 2
Reply 12, posted (6 years 2 months 2 weeks 2 days 4 hours ago) and read 2902 times:



Quoting Mcdu (Reply 11):
On our non-GPS equipped airplanes, when departing LAX on an RNAV SID we would have to do a quick alignment with the IRU's at the end of the runway to update the position of the airplane

Just out of interest - can this IRU alignment not be done on the stand with the stand co-ordinates? Almost all stands have their exact GPS co-ordinates on charts for the IR/INS units to be aligned.



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User currently offlineMcdu From United States of America, joined Apr 2005, 1466 posts, RR: 17
Reply 13, posted (6 years 2 months 2 weeks 2 days 1 hour ago) and read 2836 times:



Quoting Speedbird128 (Reply 12):
Just out of interest - can this IRU alignment not be done on the stand with the stand co-ordinates? Almost all stands have their exact GPS co-ordinates on charts for the IR/INS units to be aligned.

The IRU's are aligned on stand but there is no guarantee that they won't drift due to inadequate update souces (DME/DME). The RNAV sids require precise navigation of RNP .3. The only way assure accuracy is in a non GPS airplane is to perform a quick alignment at the end of the runway. LAX, LAS and the BOS WYLY dept procedures were the only ones that required this to be done.

It is often possible to see the runway either left of right of your correct position when taking off due to IRU drift. Once airborne it will get updated with good signals from DME/DME. This is often called a mapshift. On the non GPS airplanes when coasting in from being overwater in areas of "IRS NAV ONLY" you will sometimes have significant mapshift and the airplane will readjust its course if using LNAV.

On the 767's the IRU's automatically aligned themselves to the end of the runway on application of the EPR switch on T/O.


User currently offlineAAH732UAL From , joined Dec 1969, posts, RR:
Reply 14, posted (6 years 2 months 2 weeks 1 day 12 hours ago) and read 2723 times:

Quoting Speedbird128 (Reply 12):

Just out of interest - can this IRU alignment not be done on the stand with the stand co-ordinates? Almost all stands have their exact GPS co-ordinates on charts for the IR/INS units to be aligned.

737 classic FMCs non-GPS have a RWY POS UPDATE in the pref page(where V speeds are at) So they just click that and execute and your updated.

Also the below I quote is for non-pip and pip FMCs.... Pegasus FMCs w/o GPS don't need a re-align but IIRC.... GPS MMR was STD in the Pegasus in 1996 or 1998... so really there is not a lot of non- GPS Pegs or they have been upgraded with GPS.

Hope this helps!

Quoting Mcdu (Reply 13):
The RNAV sids require precise navigation of RNP .3.

RNP.3 is for approach only. IE DME/DME RNP0.3 NA on any RNAV approach.

Inside the terminal is RNP1 and enroute is RNP2.

IE the new FAA/ICAO filing requirement. RNVD1E2A1.

As you know there is 2 types of RNAV SID/STARs.... Type A(RNAV2) and Type B(RNAV1). B is the one used most and needs DME/DME/IRU or GPS and +-1 95% and a ton of other stuff. A is DME/DME, DME/DME/IRU, or GPS along with RNP -+2 and a lot of other stuff.

Side question..... on the OPS pages for Non-Pegasus FMCs...... it give the codes.... example-Q2 and then the LAT/LON....... do you enter Q2 is the GATE coords then LSK them or type out the LAT/LON by hand? I have always wondered that and never flew any RNAV departures at TK so I never asked.

Thanks!

[Edited 2008-07-05 20:39:43]

User currently offlineSpeedbird128 From Pitcairn Islands, joined Oct 2003, 1648 posts, RR: 2
Reply 15, posted (6 years 2 months 2 weeks 1 day 6 hours ago) and read 2652 times:



Quoting Mcdu (Reply 13):
This is often called a mapshift. On the non GPS airplanes when coasting in from being overwater in areas of "IRS NAV ONLY" you will sometimes have significant mapshift and the airplane will readjust its course if using LNAV.

Thanks for the info.

I was aware of the IRS NAV ONLY on non GPS machines and IRS/INS/IRU drift.

Quoting AAH732UAL (Reply 14):
Hope this helps!

Thanks, yes.



A306, A313, A319, A320, A321, A332, A343, A345, A346 A388, AC90, B06, B722, B732, B733, B735, B738, B744, B762, B772, B7
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