Delay for "Numbers"

[daviswh]

I frequently listen to JFK tower. I hear pilots asking for permission to delay because they are waiting for "numbers". Can somebody explain what numbers they are waiting for?  Is it weight and balance? Something else?
Thanks
Bill

[sunburn]

correct me if i'm wrong...... but i've always assumed 'numbers' is the release time.

[rpd]

No, it is not a release time.  ATC would issue that.  I think it is weight/balance info and fuel burn.  Also might be checking passenger names against the terrorist no fly lists.

[sunburn]

ah ha.
"pilots asking for permission to delay" my eyes kinda skipped over that bit and i was thinking when planes already taxi out of the gate. i should go to sleep.

[Acey]

No, it is not a release time.  ATC would issue that.  I think it is weight/balance info and fuel burn.  Also might be checking passenger names against the terrorist no fly lists.

Definitely not checking names, that's done well before. It's simply weight and balance, the pilots toss the numbers in to then get their V speeds.

[PHL Approach]

Yep, they are waiting for the rampers to send the "cargo final" and then the CSA to send the "passenger final" which then ACARS spits out your finished load sheet or it gets sent to the LPC laptop. They would be added for the Zero Fuel Weight which as Adrian mentioned is how they'll grab their V speeds/ Perf Data.

[The Hoffspatcher]

Yup.  Basicaly works that 1-3hrs before the flight leaves the Dispatcher will pull how much cargo & how many passengers have been booked on the flight and use that to get the complicator (computer) to crunch out a flight plan & dispatch release.

When the check in closes out and boarding is complete, these two numbers are compred by the magic frustrator (computer) to see if everybody that checked in got on.  Load control send the cargo weight from the rampers which goes into, again, the frustrator and it frustrates out a zero fuel weight.

That's ACARS'd off to the pilots which as Ed say, is where they get ZFW for Vspeeds/MAC & trim, pax count etc

If you would like a copy of what some frustrated numbers (computer printout) look like I can scan one.

[w0x0f]

3 questions.

1.  Why do Southwest Airlines flights seem to always have their numbers?

2.  Why don't other airlines adopt the Southwest system?  It seems to be working.

3.  How often do you think these "delays for numbers" are blamed on "ATC delays?"

Just thinking outloud.

w0x0f

[tyketto]

3 questions.

1.  Why do Southwest Airlines flights seem to always have their numbers?

2.  Why don't other airlines adopt the Southwest system?  It seems to be working.

3.  How often do you think these "delays for numbers" are blamed on "ATC delays?"

Just thinking outloud.

w0x0f

they don't have them all the time, and where I see them, it is plain to see that, outside of their release time for flow/metering.

If you look at the airport diagram for LAS, on Taxiway B adjacent to 25R, there is a holding pad. On a daily basis, I see SWA jets go into that holding pad waiting on their numbers, their release window for flow, the entire lot. Whether they announce it on Tower frequency is another thing, but I can guarantee you that if you were to tune to their company frequency, you'd hear that quite often.

BL.

[daviswh]

If you would like a copy of what some frustrated numbers (computer printout) look like I can scan one.

I'd like to see the frustrated numbers - thanks for offering

[w0x0f]

they don't have them all the time, and where I see them, it is plain to see that, outside of their release time for flow/metering.

If you look at the airport diagram for LAS, on Taxiway B adjacent to 25R, there is a holding pad. On a daily basis, I see SWA jets go into that holding pad waiting on their numbers, their release window for flow, the entire lot. Whether they announce it on Tower frequency is another thing, but I can guarantee you that if you were to tune to their company frequency, you'd hear that quite often.

BL.

I'm having trouble understanding your post.  You say that SWA aircraft are sitting in the pad waiting for flow control release times.  Then you say that they are sitting in the pad taking mysterious delays which they don't tell ATC about.  Which is it?  I work several SWA flights a day and have never seen one take a delay waiting for numbers.  Never.  The only time they will not be ready is because the F/A's are not done in the back and that is very, very rare and takes only a few extra seconds. 

  I have worked many AAL, DAL, UAL, USA, and NWA aircraft that have taken long delays of 10 - 15 minutes waiting for numbers.  Many of their routes require an APREQ and it has become common practice to ask if they have their numbers even before calling flow control for their release.  It saves the 2 extra calls to cancel the original release and then obtain a new release when the aircraft has the numbers.  You never have to ask SWA, they are always ready to go.

w0x0f

[Miyridian]

3 questions.

1.  Why do Southwest Airlines flights seem to always have their numbers?

2.  Why don't other airlines adopt the Southwest system?  It seems to be working.

3.  How often do you think these "delays for numbers" are blamed on "ATC delays?"

Just thinking outloud.

w0x0f

I seem to remember reading somewhere that Southwest crews have laptops on which they can do their own weight and balance and performance computations, and thus not have to get them from ACARS. I don't know whether it's true or not.

[tyketto]

I'm having trouble understanding your post.  You say that SWA aircraft are sitting in the pad waiting for flow control release times.  Then you say that they are sitting in the pad taking mysterious delays which they don't tell ATC about.  Which is it?  I work several SWA flights a day and have never seen one take a delay waiting for numbers.  Never.  The only time they will not be ready is because the F/A's are not done in the back and that is very, very rare and takes only a few extra seconds. 

What I am saying is that they use that pad (as well as other airlines) so when they are waiting for their numbers, or ATC had to give them a new release window because of flow or metering, they are not holding up the line of departures, or causing ATC to depart them from an intersecting runway, which would also prompt the occasional 'can you take an intersection A2 or B1 departure', and mention the number of feet available for the runway.

They (all airlines) use it for both when it is needed. Now generally, when SWA has been #1 for the runway, I haven't heard them call for a delay because they're getting their numbers; they definitely have them beforehand, or use such holding pads to get them if they don't already have them on the taxi out.

BL.

[PHL Approach]

3 questions.

1.  Why do Southwest Airlines flights seem to always have their numbers?

2.  Why don't other airlines adopt the Southwest system?  It seems to be working.

3.  How often do you think these "delays for numbers" are blamed on "ATC delays?"

Just thinking outloud.

w0x0f

I seem to remember reading somewhere that Southwest crews have laptops on which they can do their own weight and balance and performance computations, and thus not have to get them from ACARS. I don't know whether it's true or not.

Yes, you are correct. SWA does use 'laptops'. As I mentioned in an earlier post that it can be either via ACARS (industry standard) or LPC which to some airlines stands for "Less Paper in Cockpit" or in other words a laptop with a perf data calculation program etc. They are the only airline in the US that I know of to do LPC. Then again I wouldn't put it past JBU.

[w0x0f]

They (all airlines) use it for both when it is needed. Now generally, when SWA has been #1 for the runway, I haven't heard them call for a delay because they're getting their numbers; they definitely have them beforehand, or use such holding pads to get them if they don't already have them on the taxi out.

BL.

So when they sit in the pad they are taking the mysterious delays for which they don't announce the reason on ATC frequencies. 

Whether they announce it on Tower frequency is another thing, but I can guarantee you that if you were to tune to their company frequency, you'd hear that quite often.

BL.

Generally, when an aircraft reaches the runway they should be ready to go.  If they are not ready they will tell either GC or LC the reason why they are not ready.  It sounds from what you say that in Vegas SWA does not say they are waiting for numbers and just move out of the way.  The only way that one would know that it was a numbers issue is if you were listening to the SWA company frequency.  Since you have guaranteed that this is the case, then it must be true.  I have not experienced this in the thousands of SWA aircraft that I have had the pleasure to work.  I have never seen one of those thousands of aircraft not ready because of a weight and balance issue.  They are always ready.  What happens in Vegas must stay in Vegas. 

w0x0f

[aevins]

JetBlue uses 'laptops' (LPC) on their A320s, I don't know if they have them on the E190s

[dorishd]

Yes it does, and lets keep it that way!

[tyketto]

I will agree with this; Vegas is a unique issue; I haven't seen many airports with holding pads for them to pull into. Outside of the one adjacent to taxiways B and C (which I think C was just extended), there are 8 other pads there. But you're right; they are generally ready to go when they come up to the runway, but when they have to deal with flow or get their numbers if they don't already have them, they can pull into there.

Any other airports with pads like this? It's easily labeled on KLAS' airport diagram.

BL.

[The Hoffspatcher]

You can see some numbers here:  http://img217.imageshack.us/my.php?image=numberslt6.gif (71kb)

[w0x0f]

Any other airports with pads like this? It's easily labeled on KLAS' airport diagram.

There are others with run up pads.  Go to www.airnav.com to pull up other airport diagrams.  Start with ORD and their famous "penalty boxes."

w0x0f

[MathFox]

3 questions.

1.  Why do Southwest Airlines flights seem to always have their numbers?

2.  Why don't other airlines adopt the Southwest system?  It seems to be working.

3.  How often do you think these "delays for numbers" are blamed on "ATC delays?"

Just thinking outloud.

w0x0f

1: Good old pencil and paper... (Southwest uses computers for W&B now, simple PCs at airport OPS)

2: Why use pencil and paper if you have an overloaded central mainframe? Delegating trust to remote employees... *YUCK*

3: I've heard "we're waiting on some paperwork" several times in the plane. Had a "We have a one hour delay due to ATC computer failure today." 

Two relevant links to the Southwest blog:
http://www.blogsouthwest.com/2006/06/06/the-kiss-theorykeep-it-simple-southwest/
http://www.blogsouthwest.com/2007/09/13/dont-knock-a-green-cake-til-youve-had-one/

[w0x0f]

1: Good old pencil and paper... (Southwest uses computers for W&B now, simple PCs at airport OPS)

2: Why use pencil and paper if you have an overloaded central mainframe? Delegating trust to remote employees... *YUCK*

3: I've heard "we're waiting on some paperwork" several times in the plane. Had a "We have a one hour delay due to ATC computer failure today." 

Two relevant links to the Southwest blog:
http://www.blogsouthwest.com/2006/06/06/the-kiss-theorykeep-it-simple-southwest/
http://www.blogsouthwest.com/2007/09/13/dont-knock-a-green-cake-til-youve-had-one/

MathFox,

Thanks for the links.  That's just what I was looking for.  SWA just keeps it simple. 

w0x0f