BA15 LHR -SIN 5th May left with empty water tanks
May 7, 2022, 1:37 am
#31
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May 7, 2022, 2:02 am
#32
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Me too. I'd hope the pilots were aware their weight calculations were awry, and they were well over a tonne light before they left the gate.
If that reasoning holds, the decision on whether or not to fly to Singapore with empty water tanks must have taken place while the plane was on the ground at Heathrow. Siri is silent on how long it takes to fill those tanks: but if the flight could wait for crew duvets to be delivered, maybe the water-fill operation would have sent crew hours over the line or breached the airport's curfew.
Let's hope that sanctioning the omission of an expensive, but what appears to be a non-essential, element of onboard equipment doesn't excite BA's bean counters too much.
If that reasoning holds, the decision on whether or not to fly to Singapore with empty water tanks must have taken place while the plane was on the ground at Heathrow. Siri is silent on how long it takes to fill those tanks: but if the flight could wait for crew duvets to be delivered, maybe the water-fill operation would have sent crew hours over the line or breached the airport's curfew.
Let's hope that sanctioning the omission of an expensive, but what appears to be a non-essential, element of onboard equipment doesn't excite BA's bean counters too much.
May 7, 2022, 2:10 am
#33
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Not the first time we’ve had a thread about a SIN flight going without water, though in the below case over 5 years ago it was SIN-LHR. I think the water was onboard and it was the water system which failed somehow.
Everyone off BA12 tonight [SIN-LHR, 23 Sep]
After several pages of discussion, the captain (assuming they actually were the captain, but no reason to believe otherwise) posted on the thread, mainly to confirm the decision to fly was theirs alone and wasn’t made to avoid paying EC261 compensation...
https://www.flyertalk.com/forum/27257060-post98.html
Everyone off BA12 tonight [SIN-LHR, 23 Sep]
After several pages of discussion, the captain (assuming they actually were the captain, but no reason to believe otherwise) posted on the thread, mainly to confirm the decision to fly was theirs alone and wasn’t made to avoid paying EC261 compensation...
https://www.flyertalk.com/forum/27257060-post98.html
May 7, 2022, 3:09 am
#34
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The self-loading cargo isn't weighed, nor is the cargo that they schlep on board themselves, and the airline uses educated guesswork for this part of the payload. The 787-9 may have about 230 occupants when full. An average 5 kg error per person would be well over a tonne, yet there seems to be no hysteria about this possibility, which is simply just a known unknown.
In addition, does the 787-9 have stuff to help with trim once airborne, like shifting fuel about?
If the aircraft did depart without this being noticed, then it's pretty poor. And once airborne, the crew have to go through the same decision-making process about whether to live with a non-critical problem or to inflict a 24-hour delay on all the passengers as if the system had just broken down (as in other cases). But if it isn't a safety-of-flight issue, let's not go overboard about that.
And if you really want a genuinely toe-curling example of (many) things that should have been checked, but weren't, before the aircraft got airborne, try the ATSB's website for the recent report on 9M-MTK at BNE. If you don't want to be scared, don't read it.
May 7, 2022, 3:39 am
#35
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years ago on a flight to Orlando an issue arose and the Captain told us he was speaking to the ‘company’ as to wether to continue or return - we went back , would assume here the Captain was told to continue
May 7, 2022, 3:54 am
#37
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May 7, 2022, 4:14 am
#38
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I'd be interested to hear from pilots whether a tonne would make any significant difference to the weights/speed/trim calculations.
The self-loading cargo isn't weighed, nor is the cargo that they schlep on board themselves, and the airline uses educated guesswork for this part of the payload. The 787-9 may have about 230 occupants when full. An average 5 kg error per person would be well over a tonne, yet there seems to be no hysteria about this possibility, which is simply just a known unknown.
In addition, does the 787-9 have stuff to help with trim once airborne, like shifting fuel about?
If the aircraft did depart without this being noticed, then it's pretty poor. And once airborne, the crew have to go through the same decision-making process about whether to live with a non-critical problem or to inflict a 24-hour delay on all the passengers as if the system had just broken down (as in other cases). But if it isn't a safety-of-flight issue, let's not go overboard about that.
The self-loading cargo isn't weighed, nor is the cargo that they schlep on board themselves, and the airline uses educated guesswork for this part of the payload. The 787-9 may have about 230 occupants when full. An average 5 kg error per person would be well over a tonne, yet there seems to be no hysteria about this possibility, which is simply just a known unknown.
In addition, does the 787-9 have stuff to help with trim once airborne, like shifting fuel about?
If the aircraft did depart without this being noticed, then it's pretty poor. And once airborne, the crew have to go through the same decision-making process about whether to live with a non-critical problem or to inflict a 24-hour delay on all the passengers as if the system had just broken down (as in other cases). But if it isn't a safety-of-flight issue, let's not go overboard about that.
Passengers' contribution to the payload is assessed as an average: and as with averages and large numbers, individual discrepancies tend to level out in the wash. Suggesting that because that final tally of passengers might be a little out, other payload miscalculations can be disregarded seems a tad, well, cavalier.
An additional tonne or so of payload is significant. I'm sure it's a manageable unknown, but it's another hole in that Swiss cheese.
It's something pilots would want to know about, expect to know about, before they leave.
In this case i simply hypothesise they did know.
I don't see any hysteria, nothing overboard: maybe a little fig-leaf repositioning in the response though
May 7, 2022, 4:45 am
#39
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So much wild hysteria about a bit of water when, as mentioned already, there are 200 unweighed lumps of flesh and bones onboard who could each weigh anywhere between 50 and 130kg easily. Put another way, the missing potable water is 0.4% of the estimated take off weight of the aircraft on that day. This flight was some way off "OMG we could have plunged into the Wraysbury Reservoir".
May 7, 2022, 5:03 am
#40
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As has been mentioned by IAN-UK there are a lot of fudge factors in load and balance calculations.
We know the empty weight of the aircraft and they are weighed on a regular basis, we also know the weight on the catering and all of its equipment. We know the weight of the cargo and the Mail and all of the baggage. The human beings are total guess work but organisations such as the CAA and the likes of IATA (iirc) do regular sample audits of human traffic weights.
As such we use different assumption for the mass of humanity based on regions of the world in longhaul. USA is more mass or weight per head than the Far East. But is is all still a guess and a fudge.
Given so many variables can change right up to the last minute prior to that last hold or cabin door closing, we base all of our take off performance calculations on an assumed weight based off of a ‘provisional loadsheet’. This complies with all of the regulatory performance requirements and our performance when using take off thrust de-rates and assumed temperature method (or FLEX temp in Airbus terms) thrust reductions, we are inherently safe as we are actually producing more thrust than the performance calculation allows for (the air is denser than what we have told the aircraft it is).
Given these assumptions, and due to the fact that the payload tends to go down rather than up due to late arriving bags/cargo etc, we have a tolerance on the fleet in question of +1000 to -4000KGs allowable difference between the ‘provisional’ figures and the actual or ‘final’ figures. We typically receive those just as we commence the taxi after engine start. From doors closed the turn around manager/coordinator has now been able to input any changes to the planned load and communicate that with load control, who in turn send us the final figures through an acars message. If we don’t get it, we call them up.
With regards to the water…..we don’t typically fill the tank full unless going somewhere that the potable water has failed certain tests. So we are taking about less than 1000 kgs of weight, but a bit more than 500Kgs. Given all the other assumptions we really wouldn’t notice, especially when taking off around the 210 to 220-ish tonne mark for a flight of this length.
The only change that might have occurred would be with aircraft trim, and that is merely adjusting the datum point for the horizontal stab whilst taxiing out and not an uncommon occurrence, and one highlighted through a procedure we follow to ensure data is ‘in compliance’ with this or appropriately replan and recalculate if there are ‘changes to’ the provisional figures outside of allowable tolerances.
Given the state of resourcing with various service partners airport wide, I would be sceptical of stories that the water was simply forgotten. The attendant panel is accessed a good few times pre departure by the IFM/L and various inputs are needed, such as the passenger head count figure. Given there is a TRM/C who needs to update load control with actual figures I have a feeling this was probably more to do with no staff available to service the tanks without incurring a significant and sizeable delay….or that there was a problem with the potable water system once under way.
We know the empty weight of the aircraft and they are weighed on a regular basis, we also know the weight on the catering and all of its equipment. We know the weight of the cargo and the Mail and all of the baggage. The human beings are total guess work but organisations such as the CAA and the likes of IATA (iirc) do regular sample audits of human traffic weights.
As such we use different assumption for the mass of humanity based on regions of the world in longhaul. USA is more mass or weight per head than the Far East. But is is all still a guess and a fudge.
Given so many variables can change right up to the last minute prior to that last hold or cabin door closing, we base all of our take off performance calculations on an assumed weight based off of a ‘provisional loadsheet’. This complies with all of the regulatory performance requirements and our performance when using take off thrust de-rates and assumed temperature method (or FLEX temp in Airbus terms) thrust reductions, we are inherently safe as we are actually producing more thrust than the performance calculation allows for (the air is denser than what we have told the aircraft it is).
Given these assumptions, and due to the fact that the payload tends to go down rather than up due to late arriving bags/cargo etc, we have a tolerance on the fleet in question of +1000 to -4000KGs allowable difference between the ‘provisional’ figures and the actual or ‘final’ figures. We typically receive those just as we commence the taxi after engine start. From doors closed the turn around manager/coordinator has now been able to input any changes to the planned load and communicate that with load control, who in turn send us the final figures through an acars message. If we don’t get it, we call them up.
With regards to the water…..we don’t typically fill the tank full unless going somewhere that the potable water has failed certain tests. So we are taking about less than 1000 kgs of weight, but a bit more than 500Kgs. Given all the other assumptions we really wouldn’t notice, especially when taking off around the 210 to 220-ish tonne mark for a flight of this length.
The only change that might have occurred would be with aircraft trim, and that is merely adjusting the datum point for the horizontal stab whilst taxiing out and not an uncommon occurrence, and one highlighted through a procedure we follow to ensure data is ‘in compliance’ with this or appropriately replan and recalculate if there are ‘changes to’ the provisional figures outside of allowable tolerances.
Given the state of resourcing with various service partners airport wide, I would be sceptical of stories that the water was simply forgotten. The attendant panel is accessed a good few times pre departure by the IFM/L and various inputs are needed, such as the passenger head count figure. Given there is a TRM/C who needs to update load control with actual figures I have a feeling this was probably more to do with no staff available to service the tanks without incurring a significant and sizeable delay….or that there was a problem with the potable water system once under way.
Last edited by Sigwx; May 13, 2022 at 7:00 am
May 7, 2022, 5:58 am
#41
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I once did LGW-OAK on a 777-200 that is best described as "knackered." I don't recall any announcement, but the sinks didn't work and some sanitising wipes had been placed there instead. Don't remember if tea/coffee was available though I believe I was more interested in champagne anyway.
I had assumed it was a fault given the state of the plane in general but it could perhaps have been lack of water. Either way, no one was particularly bothered by it as far as I was aware.
I had assumed it was a fault given the state of the plane in general but it could perhaps have been lack of water. Either way, no one was particularly bothered by it as far as I was aware.
May 7, 2022, 8:37 am
#42
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Originally Posted by Sigwx
or that there was a problem with the potable water system once under way.
All the way northwards past all the T5B stands to Taxiway Bravo, at which point we stopped. And stayed stopped. Oh, NOOOO! Eventually Captain Speaking came on the loudspeakers and explained they were trying to rectify a fault with the Potable Water Pump [or something like that] … which happily they succeeded in doing.
May 7, 2022, 8:50 am
#44
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At least with the 777 you can beat the aircraft into submission with the use of a bigger wrench.
The 787 alas requires a soothsayer with the temperament of a Buddhist monk, blessed with positive juju and the infinite wisdom and ethereal mythical power of sometime who can programme in both python and basic at the same time.
The 787 alas requires a soothsayer with the temperament of a Buddhist monk, blessed with positive juju and the infinite wisdom and ethereal mythical power of sometime who can programme in both python and basic at the same time.