JQ MEL - PER Diverted to ADL

[stiffwing]

Roger. If your statement is correct (and I'm not misunderstanding you) then
- They took off with grossly inaccurate weights (about 200 x 100kgs)
- There was no comment passed when the loadsheet presented with only 1 pax, rather than 201
- There was no comment with a grossly different final ZFW compared with the provisional ZFW (about 20 tons??)
- the tech crew were expecting 1 pax and the cabin crew got 201?

Please correct me if wrong

[Roger Standby]

Stiffwing,

Not saying that the manifest showed 1 pax, but that the system for calculating fuel weights is flawed. The numbers quoted were as an example.

As to the rest of your questions, yes, that is what I have been told.

I seriously hope that I have been misinformed and that someone will shoot this theory down.

[Ndicho Moja]

If what I read here, especially over the last few posts, is in fact the case, may I ask, what happened to gross error checks of flight plans? For the A320, flight planned time in minutes x 38Kg (light weight) or minutes x 43Kg (heavier weights), is a ball park figure for flight fuel. Add to these figures all the required reserves and one is within a bulls roar of fuel required.

Surely there must be more to this turn-back than what is being written here?

[Roger Standby]

The silence is deafening. I thought someone would have shot me down by now...

[Hempy]

RS,

If what you are saying proves to be correct, and there is a software error of that nature, surely this would have been picked up by someone in house (I mean, if J* regularly overbook this would have manifested itself before now, and no ones fallen out of the sky yet). That being the case, it would be a known problem, one that would seem serious enough to need rectifying ASAP (considering the consequences of a "green" (i.e. the known problem wasn't known to them) dispatcher giving the pilots bad numbers...not too many alternates over the bite). No wonder the silence is deafening......

[toolish]

unfortunately we are getting used to being supplied with incorrect data therefore most of us are getting used to filling in the holes however the risk of this happening is always present

[Mstr Caution]

If the flight plan fuel was calculated in error on a "light load" then:

a. If the ZFW increased dramatically preflight (and entered in FMC) wouldnt the FMC produce a scratchpad message to the effect "insufficient fuel"

b. If the ZFW error was not identified & the wrong ZFW entered into the FMC. Then wouldnt all the takeoff calculations of takeoff speeds & thrust be in error.

therefore

c. If reduced thrust takeoff used for the incorrect weight. Wouldnt the takeoff acceleration be unusually lower.

Perhaps someone with A320 experience could tell me, isnt the aircraft system designed to catch such errors? Is there a ECAM message something like "STAB BAND" which would appear if the FMC programmed weights differ to that in which the nose gear senses as actual aircraft weight?

[cunninglinguist]

Jet* planning software is limited in that if a flight is overbooked, the data resets itself. Ie. if the a/c has 200 seats for example and the flight has 201 seats booked, the planner clocks itself and shows the pax numbers as 1!

News to me, however I think the dumbest pilot would look at that and be a little suspect, only time I carried close to 1 pax was on a ferry. Also, normally, most guys/gals carry enough " fat " to cover the difference in fuel burn, especially on a long night flight.

I seriously hope that I have been misinformed and that someone will shoot this theory down.

Yes you have, there is no way they would have blasted off with a difference in pax of that magnitude, or any magnitude for that matter, the PDA docket has to match the Cabin Crew count, simple.

Surely there must be more to this turn-back than what is being written here?

Yep, you can bet on it, I don't know but as mentioned earlier PH wx forecast is quite often dodgy, especially with fog.

If the ZFW increased dramatically preflight (and entered in FMC) wouldnt the FMC produce a scratchpad message to the effect "insufficient fuel"

No

If the ZFW error was not identified & the wrong ZFW entered into the FMC. Then wouldnt all the takeoff calculations of takeoff speeds & thrust be in error.

V speeds are manually inserted by the pilots, which are taken from the TOLD card after obtaining from the RTOW book

Is there a ECAM message something like "STAB BAND" which would appear if the FMC programmed weights differ to that in which the nose gear senses as actual aircraft weight?

No such message, and to the best of my knowledge, no weight sensor in nose gear. The only message that even slightly applies to the above is " CHECK GW " which only shows if the FMC and FAC computed weights differ by more that
7T. (this is based on pilot inserted data, and the GW computed by the FAC via AoA etc )