Take-off weight

[Alan Biles]

Hi all,
Not sure this is the right place for this question but..... I just booked me and Mrs B on BA LGW-TPA and noted that the baggage allowance is 23kg each + up to 23kg each hand baggage. Mrs B is also allowed a handbag (and God only knows how much that weighs). How then is an accurate take-off weight arrived at or is it just a wet-finger-in-the-air job?

[john_tullamarine]

If done sensibly and based on actual statistics appropriate to a given population AND on larger capacity aircraft, the use of average weights (pax and bags) works out pretty well.

Careless application mismatching inappropriate populations (eg the stats were based on a typical population and you are carrying a bunch of folks to a sumo wrestling convention) or use on small seating capacity aircraft is where it breaks down badly.

[framer]

How can you carry 23kg of hand baggage? Where would you put it? I can hardly lift that onto the scales let alone into an overhead locker.

[BOAC]

Hand baggage allowances | Baggage essentials | British Airways (http://www.britishairways.com/en-gb/information/baggage-essentials/hand-baggage-allowances)

[JammedStab]

If done sensibly and based on actual statistics appropriate to a given population AND on larger capacity aircraft, the use of average weights (pax and bags) works out pretty well.

Careless application mismatching inappropriate populations (eg the stats were based on a typical population and you are carrying a bunch of folks to a sumo wrestling convention) or use on small seating capacity aircraft is where it breaks down badly.

I have seen in a company where there the official average weight is increased a specific amount for sports charters, hunting groups, military personnel groups, etc.

[BOAC]

..and for 'certain' countries to allow for chicken, goats and rolled up carpets...........etc etc:D

[172_driver]

For European operators (I use European since BA qualifies) the regulations provide for standard masses that can be, and is, used for simplicity. That would be 84 kg for adults, 35 kg for children, and includes hand luggage. The standard mass for your hold luggage on such a route (intercontinental) would be 15 kg.

There is of course the possibility that BA have some other deal negotiated with their supervising authority. But the numbers above I would say are the ones most widely used.

[john_tullamarine]

the numbers above I would say are the ones most widely used

Unless the numbers are based on a rational statistical analysis with sensible error bounds on their subsequent use, they are not a great deal of use so far as validity is concerned.

Australia uses data originally developed by CASA's then John Klingberg some years ago based on medical statistical data for the then Australian population. John's original report makes for interesting reading - the final operational output is at CAAP 235-1(1) (http://www.casa.gov.au/wcmswr/_assets/main/download/caaps/ops/235_1.pdf)


It follows that any study periodically needs to be revisited to maintain a semblance of policy validity.

[172_driver]

The numbers come straight from EU-OPS. If they're sensible or not would require a scientist to determine, but they have legal status:

This Regulation shall be binding in its entirety and directly applicable in all Member States.

Done at Brussels, 20 August 2008.



In those airlines I've had something to do the same weights have been used for 10+ years. Considering the explosion of low fare airlines charging you extra for hold bags, the weight of the average hand luggage must have trebled ever since. I heard an anecdote; after 9/11 some airlines changed their procedure to actually weigh the luggage. After realizing how many flights were then operating over-weight with the new system, they swiftly changed back to standard weights again. Could be an urban myth, too.

Since under estimated standard weights would really only manifest itself on a performance limited take-off with engine failure at, or around, V1 the "inconvenience" to re-visit the science may not outweigh the benefits anytime soon?

[john_tullamarine]

After realizing how many flights were then operating over-weight

While this may be true for some circumstances, my experience for those flights which were critically weight limited and for which we then weighed everyone and everything ... showed the opposite.

Providing the stats have been done appropriately and are relevant to the subject population .. once you get a reasonable number of seats involved, the variations even out and the standard weights provide a very sound prediction of actual weight.

[Natstrackalpha]

Quote BOAC "..and for 'certain' countries to allow for chicken, goats and rolled up carpets...........etc etc:D"


There was also that World championship weight lifting competition in San Francisco.. . . :):uhoh: