Take-off data calculations whilst Taxiing
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What if there is a discrepancy on total pax onboard when they receive the final loadsheet?
Do they taxi back to stand?
Do they taxi back to stand?
The system allows for variation in pax numbers and loading within certain tolerances before generating a CHANGES message. The change tolerances vary by aircraft type (less tolerance for a small aircraft, as you would expect), and will be for TOW and trim. Outside the tolerance and you have to inspect the changes and re-confirm the performance data. Note: the TOW may be down - it is rarely up, as they factor the male/female split after doors closed, and the performance is generally in your favour. On the 747, you normally find that the assumed temp thrust reduction methos gives you 2-3 tonnes or margin, which equates to 20-30 pax increase! and is therefore rarely a factor.
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Ouch, why give the holes in the Swiss cheese more chances - the amount of ZFW changes over 4000 kg`s are not that infrequent to be ignored ie: sorted out on the way to the runway.
1. On Airbus FBW once the engines are started you can no longer enter the ZFW as a ZFW but must enter the weight as a Gross weight on a different page which the a/c will then work backwards to a ZFW - so a different page with a different input means a non standard way - anything thats non standard needs more attention.
2. Your paper flightplan generated on the ground by a ground based computer becomes less and less relevant as the ZFW changes - when do you ask for a new one. 4000 Kg seems to work for the 340.
3. Yes it is also possible to uplink the whole shooting match to glass aircraft - sort of removes the drivers airframe from the loop to a large extent: who selects how much you flex/ de-rate which V1 to use ,anti - ice, flap settings etc... Getting the correct information to the a/c is important then let the people in front make the plan.
Yes we have to do change figures when it`s unavoidable - runway change, sudden rainstorm with a now wet runway. Why leave the gate with something so important still incomplete? If you are still at the gate and you are not 100% happy there is no pressure - I`v been in a situation where we opened the cargo doors to double check due to a 2nd ACARS "final" loadsheet 15000 Kg lighter.
Less haste - More speed
1. On Airbus FBW once the engines are started you can no longer enter the ZFW as a ZFW but must enter the weight as a Gross weight on a different page which the a/c will then work backwards to a ZFW - so a different page with a different input means a non standard way - anything thats non standard needs more attention.
2. Your paper flightplan generated on the ground by a ground based computer becomes less and less relevant as the ZFW changes - when do you ask for a new one. 4000 Kg seems to work for the 340.
3. Yes it is also possible to uplink the whole shooting match to glass aircraft - sort of removes the drivers airframe from the loop to a large extent: who selects how much you flex/ de-rate which V1 to use ,anti - ice, flap settings etc... Getting the correct information to the a/c is important then let the people in front make the plan.
Yes we have to do change figures when it`s unavoidable - runway change, sudden rainstorm with a now wet runway. Why leave the gate with something so important still incomplete? If you are still at the gate and you are not 100% happy there is no pressure - I`v been in a situation where we opened the cargo doors to double check due to a 2nd ACARS "final" loadsheet 15000 Kg lighter.
Less haste - More speed
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Groundfloor
5 tonnes on a 747.
You clearly do not understand how the Provisional Loadsheet system works, perhaps we haven't explained properly - either way, we have been using them for 18+ years in BA, with advances (ACARS etc rather than voice) and belts and braces in procedures along the way to try to ensure integrity of the calculations for performance. Thus far it has worked for about 700 departures per day (x 365 x 18) = 4.5 million flights, without any MEL/AKL type incidents.
When you can statistically argue your case from a position of knowledge and experience, then come back and argue it
2. Your paper flightplan generated on the ground by a ground based computer becomes less and less relevant as the ZFW changes - when do you ask for a new one. 4000 Kg seems to work for the 340.
You clearly do not understand how the Provisional Loadsheet system works, perhaps we haven't explained properly - either way, we have been using them for 18+ years in BA, with advances (ACARS etc rather than voice) and belts and braces in procedures along the way to try to ensure integrity of the calculations for performance. Thus far it has worked for about 700 departures per day (x 365 x 18) = 4.5 million flights, without any MEL/AKL type incidents.
When you can statistically argue your case from a position of knowledge and experience, then come back and argue it
I really don't know why this topic is such news. The first time I came across getting the "final figures" whilst taxiing out was on my way to the reef runway at Honolulu on my way to Nadi.
The year was 1983.
So what is new?
Why do you want to know where everyone is sitting?
In Laker (British CAA) we had to list exactly how many passengers were sitting in Compartment A, B and C (DC10) and whether they were male, female or children.
When I flew the exact same aircraft on the N register, the FAA were not so insistent upon such detailed information.
They only required the total passenger numbers for they figured that the first passengers on board would sit by the windows, the second lot would sit in the aisles and the remainder would fill the middle seats.
I do not ever remember such a practical solution ever causing me the slightest problem.
Life is basically simple; only people make it complicated.
The year was 1983.
So what is new?
Why do you want to know where everyone is sitting?
In Laker (British CAA) we had to list exactly how many passengers were sitting in Compartment A, B and C (DC10) and whether they were male, female or children.
When I flew the exact same aircraft on the N register, the FAA were not so insistent upon such detailed information.
They only required the total passenger numbers for they figured that the first passengers on board would sit by the windows, the second lot would sit in the aisles and the remainder would fill the middle seats.
I do not ever remember such a practical solution ever causing me the slightest problem.
Life is basically simple; only people make it complicated.
I find nothing wrong with how BA do the loadsheet thing for as long as they are not allowed to hold things up at the departure end.
I would however like to know what on earth you BA lot are doing post push-back and prior to taxi (other than starting up)? Seems to take BA longer than most to get ready for taxi. I especially notice this at the BA terminal at JFK. What are you folks up to?
I would however like to know what on earth you BA lot are doing post push-back and prior to taxi (other than starting up)? Seems to take BA longer than most to get ready for taxi. I especially notice this at the BA terminal at JFK. What are you folks up to?
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Late "final numbers" were an issue with the previous company I worked for. However the ATC at my base was fully aware and an informal procedure was in place where on first contact with GND, the pilot would call:
"XXX####, (position) with numbers / negative numbers"
Then you either get the taxi to the runway or join the rest of the guys in the holding bay.
Present company all is done 20min prior to gate departure.
"XXX####, (position) with numbers / negative numbers"
Then you either get the taxi to the runway or join the rest of the guys in the holding bay.
Present company all is done 20min prior to gate departure.
oceancrosser
What this lot "is up to" is the little matter of getting Air Traffic permission to move....
Unlike most airports the normal procedure at JFK is that when ready to taxi you call the first Ground Frequency, that controller puts you in the system as ready for taxi, then hands you off to the next Ground Controller who will eventually clear you to start taxiing and actually leave the BA Ramp area and join the line out to the runway ...... I suspect
it's a similar deal for any airline taxiing at JFK.
Unlike most airports the normal procedure at JFK is that when ready to taxi you call the first Ground Frequency, that controller puts you in the system as ready for taxi, then hands you off to the next Ground Controller who will eventually clear you to start taxiing and actually leave the BA Ramp area and join the line out to the runway ...... I suspect
it's a similar deal for any airline taxiing at JFK.
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I have waited behind aircraft's not ready because of performance calculations, (waiting for final numbers) and it is unacceptable.
If you are not done with absolutely everything, don't push!
ATC shouldn't allow a/c to push until final figures received, period.
Ready on reaching...........
If you are not done with absolutely everything, don't push!
ATC shouldn't allow a/c to push until final figures received, period.
Ready on reaching...........
Hardly Never Not Unwilling
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As I am paid by the minute and not by the mile, I'm not too concerned if the airplane ahead of me needs a minute or two for whatever reason.
Common courtesy suggests, though, that you shouldn't pass the last escape from blocking the runway without numbers if possible.
In my experience, 80 percent of the time the numbers come right after pushback as the first engine is being started, and 99.9 percent of the time all checklists are complete by the time I'm cleared for takeoff. In that rare, rare case when I'm not ready I've found the following to work: "Tower, we need a few more minutes, what would you like us to do?"
Would that make anyone angry if they heard that? If so, I believe the problem is yours, not mine.
Common courtesy suggests, though, that you shouldn't pass the last escape from blocking the runway without numbers if possible.
In my experience, 80 percent of the time the numbers come right after pushback as the first engine is being started, and 99.9 percent of the time all checklists are complete by the time I'm cleared for takeoff. In that rare, rare case when I'm not ready I've found the following to work: "Tower, we need a few more minutes, what would you like us to do?"
Would that make anyone angry if they heard that? If so, I believe the problem is yours, not mine.
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ATC should make aircraft that are not ready at the hold, enter the runway and vacate to the back of the queue.
As an aside I have noticed BA takes an extraordinary time to request taxi after pushback at HKG as well.
As an aside I have noticed BA takes an extraordinary time to request taxi after pushback at HKG as well.
Person Of Interest
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silly, silly, silly...The Captain should koow how much the A/C weighs, how much fuel is on board (minus taxi fuel-which as we all know is always stated on the "lean" side) and how much payload is onboard...
Time to go is time to go...If one can;t figure it out without computers and ACARS, well, maybe one should bring back the trusted F/E...
Time to go is time to go...If one can;t figure it out without computers and ACARS, well, maybe one should bring back the trusted F/E...
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well, maybe one should bring back the trusted F/E...
We never 'lost' him.
...but in my airline we do EVERYTHING at the gate, even briefing, if possible.
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My company uses the provisional system as well but we get final before pushback, we allow 3 mins between final loadsheet arrival to pushback to enter into FMC and finish checklist. No head down calcs whilst taxying!
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The Ba a/c do take significantly longer to get fully ready for departure at DXB which is not a problem if you are taxying for a 30R departure but I always try to put them somewhere that I can get other traffic to the holding point ahead of them as it can be a solid 5 minute delay at the 12R holding point.
Never mind ATC and the guys behind them in the queue, if I were on the flight deck i`d be geting a bit hacked off with it too which can`t be the best way to start your journey.
Never mind ATC and the guys behind them in the queue, if I were on the flight deck i`d be geting a bit hacked off with it too which can`t be the best way to start your journey.
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There are too many people here who aren't reading what's written; either because they are skipping the information or because they chose not to so they can 'BA bash'.
The performance calculations are NOT done whilst taxying. They are done before push-back and the FMC entries are complete before push-back. The calculations are done using the provisional figures, from a loadsheet that is signed by the Captain (as required by law). In the time I flew for BA I only had a ZFW that was higher than the provisional loadsheet a handful of times and, even then, the new TOWs were well within the assumed temperature TOWs that had been calculated and entered into the FMC BEFORE push-back, so nothing had to be touched (and no delays caused as a result).
So, the reasons for the delays? Generally two. The first concerns some places (JNB a classic example) where the groundstaff are so crap at getting the final figures into the system and then sent via ACARS to the aircraft that the pilots are left waiting for them. For obvious reasons they are not going to get airborne without them, so they have to wait. The trouble is, it's not consistent. So it's no good asking ATC for a delay tactic as you await your final figures because you can bet on that occasion they will come through straight away. The stations that cause the most problems have been told time and time again to sharpen up but what do you do? In JNB the station staff do not answer the radio, they do not answer their mobile phone numbers as posted on the info sheets and, the last time I was there, the only way we could contact them was for us to ring London on Satcom and then get LHR Operations to call JNB direct. Not ideal, as you can see, and certainly not the fault of the pilots if some people are delayed whilst taxying in these 2-bit locations. The second reason for delays are because the cabin is not secure. We've gone round and round on this one hundreds of times but, at the end of the day, for whatever reasons, until everybody is briefed and buckled in then the aircraft ain't going anywhere. Most airlines are better than BA at getting the cabin ready quickly, simple as that but, again it's not consistent and some crews are excellent at getting the cabin ready. If you're frustrated in JNB, just imagine the poor air traffic controllers at LHR
.
So, is there a safety issue here? Definitely not. I've done it the BA way and I've done it other ways. BA do not calculate whilst taxying and the SOPs for data entry and calculations are better than the other outfits I've flown for. They are far more stringent on doing these things in a set manner and there is far less room for pilot judgement (and, therefore, mistakes). So, for the scaremongerers; back in your box. Just because you wait for the final figures at the gate doesn't mean that's the way it has to be done (especially with pax flying versus cargo flying) and, as has been pointed out, BA's success rate is testomony to the fact that it's not dangerous. As for the EK incident; I do not have a clue about EK's SOPs for ensuring the data is cross-checked and entered correctly (IF that had anything to do with the tailscrape at all). All I can say is that BA's procedures do ensure everything is on the safe side and there is absolutely no safety issue involved.
Why do BA take so long to push and start i.e. why is it so long before they can taxy? Well, I would suggest that at the stations mentioned CPT, HKG & JNB it is a function of temperature/airfield elevation. At all of these places we're talking about BA 744s. Normally they would start 2 engines at a time but, when the temps get up they have to start one engine at a time and, in the case of JNB, they will be doing manual starts as well (as opposed to auto-starts). Again, for obvious reasons, this is going to take a lot longer than normal and may well be why you see the clock ticking longer between pushing and being ready to taxy. The old accusations of slow taxying for extra money etc went out the window with the flying boats. It's got nothing to do with extra cash, nor trying to piss other people off because, at the end of the day, the BA pilots want to get in the air just as quickly as you do. Can you really imagine, for one moment, that it is a lifelong ambition of a BA crew to be sitting looking at the taxyway markings in JNB?
I have no vested interest in the way BA do things, as I no longer fly for them. What I can say, however, is that cries of 'unsafe' or 'dangerous' are so far off the mark that they should be consigned to the bull**** pile. Inconvenient for other airport users, certainly, but hopefully you'll now know why those BA Jumbos are taking so long to get into the ether and realise it has got nothing to do with trying to piss anyone off.
The performance calculations are NOT done whilst taxying. They are done before push-back and the FMC entries are complete before push-back. The calculations are done using the provisional figures, from a loadsheet that is signed by the Captain (as required by law). In the time I flew for BA I only had a ZFW that was higher than the provisional loadsheet a handful of times and, even then, the new TOWs were well within the assumed temperature TOWs that had been calculated and entered into the FMC BEFORE push-back, so nothing had to be touched (and no delays caused as a result).
So, the reasons for the delays? Generally two. The first concerns some places (JNB a classic example) where the groundstaff are so crap at getting the final figures into the system and then sent via ACARS to the aircraft that the pilots are left waiting for them. For obvious reasons they are not going to get airborne without them, so they have to wait. The trouble is, it's not consistent. So it's no good asking ATC for a delay tactic as you await your final figures because you can bet on that occasion they will come through straight away. The stations that cause the most problems have been told time and time again to sharpen up but what do you do? In JNB the station staff do not answer the radio, they do not answer their mobile phone numbers as posted on the info sheets and, the last time I was there, the only way we could contact them was for us to ring London on Satcom and then get LHR Operations to call JNB direct. Not ideal, as you can see, and certainly not the fault of the pilots if some people are delayed whilst taxying in these 2-bit locations. The second reason for delays are because the cabin is not secure. We've gone round and round on this one hundreds of times but, at the end of the day, for whatever reasons, until everybody is briefed and buckled in then the aircraft ain't going anywhere. Most airlines are better than BA at getting the cabin ready quickly, simple as that but, again it's not consistent and some crews are excellent at getting the cabin ready. If you're frustrated in JNB, just imagine the poor air traffic controllers at LHR
.So, is there a safety issue here? Definitely not. I've done it the BA way and I've done it other ways. BA do not calculate whilst taxying and the SOPs for data entry and calculations are better than the other outfits I've flown for. They are far more stringent on doing these things in a set manner and there is far less room for pilot judgement (and, therefore, mistakes). So, for the scaremongerers; back in your box. Just because you wait for the final figures at the gate doesn't mean that's the way it has to be done (especially with pax flying versus cargo flying) and, as has been pointed out, BA's success rate is testomony to the fact that it's not dangerous. As for the EK incident; I do not have a clue about EK's SOPs for ensuring the data is cross-checked and entered correctly (IF that had anything to do with the tailscrape at all). All I can say is that BA's procedures do ensure everything is on the safe side and there is absolutely no safety issue involved.
Why do BA take so long to push and start i.e. why is it so long before they can taxy? Well, I would suggest that at the stations mentioned CPT, HKG & JNB it is a function of temperature/airfield elevation. At all of these places we're talking about BA 744s. Normally they would start 2 engines at a time but, when the temps get up they have to start one engine at a time and, in the case of JNB, they will be doing manual starts as well (as opposed to auto-starts). Again, for obvious reasons, this is going to take a lot longer than normal and may well be why you see the clock ticking longer between pushing and being ready to taxy. The old accusations of slow taxying for extra money etc went out the window with the flying boats. It's got nothing to do with extra cash, nor trying to piss other people off because, at the end of the day, the BA pilots want to get in the air just as quickly as you do. Can you really imagine, for one moment, that it is a lifelong ambition of a BA crew to be sitting looking at the taxyway markings in JNB?
I have no vested interest in the way BA do things, as I no longer fly for them. What I can say, however, is that cries of 'unsafe' or 'dangerous' are so far off the mark that they should be consigned to the bull**** pile. Inconvenient for other airport users, certainly, but hopefully you'll now know why those BA Jumbos are taking so long to get into the ether and realise it has got nothing to do with trying to piss anyone off.
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FlexibleResponse
Please tell me that you are working for an African or other third-world small aircraft airline?
Please tell me that you are working for an African or other third-world small aircraft airline?
Recent incidents in Amsterdam, France, Spain, Japan, Buffalo NY, etc appear to suggest that accidents/poor operating procedures are not strictly the preserve of the 'culturally backwards', as you appear to indicate.
sAx