Heavy Bags?!?!?

[frnikolai]

Hi,

I have been thinking about a potential flaw in safety. I am sure airlines address it, but perhaps someone can enlighten it.

Most airlines offer an online check-in scheme, and more people take carry on luggage than ever before, which means YOU decide what to carry - which determines the weight. Now, Aer Lingus gives 6kg allowance - and Easyjet doesn't have one? These are just two for an example!

How can any airline monitor that people are not carrying bags of 30 kilos on-board?

I have been told that pilots make a sort of calculation to determine the weights.

If the airline says maximum weight for carry on's is 20 kilos - and the is 189 people = 3780kg. Now, if everyone takes 35 kilos - total weight = 6615. Overweight by, 2835 kilos!!!

I hope someone can answer these questions and tell me that this is taking care of!

Thank you for you're time.

Nikolai.

[raffele]

Obviously with online check-in removing formal baggage checks it gets difficult to monitor carry on baggage, however cabin crew I'm sure will be able to notice those who are struggling to lift their 30kg bag into the overhead bins, investigate and make them check it in.

Plus, from what I can remember, overhead bins tend to have a weight limit of about 20-25kg anyway...

[BOFH]

The metal detector always finds my plutonium, alas :{ , so it goes as checked baggage.

Just to put your mind at rest. How much do you weigh, and how much do you think I weigh, and how much do you think my best mate weighs, and how much does a certain senior US aviator who posts here (sometimes) weighs? Nominally, we're 75kg.

I know that there was a prang about 50 years ago with a bunch of Rugby supporters returning on a charter, where unsecured cabin luggage moved aft and changed the CoG, but we've moved on from there. It might have been a Tudor.

This concern, like the 'drunken' pilot, 'asleep at the controls', 'minimal fuel' and all the other red herrings which have so far failed to turn commercial aircraft into lawn darts, can safely be dismissed.

In a private, light aircraft, yes, it is absolutely imperative that the passengers' payload (including their meatload) be properly accounted for.

BOFH

[Bealzebub]

You raise an interesting subject Frnikolai, although your illustrations are very wide of the mark.

We use two types of weights (or masses.) The first is actual and the second is notional. The former is self explanatory in that things are weighed on a set of scales and the resultant weights used. In large aircraft it would be very unusual to weigh the passengers (Can you ever remember being weighed at check-in?) However it is not uncommon for checked baggage to be weighed in. At most check-in counters, you place your case on a weigh belt where the result is shown on a monitor and the weight is recorded.

Notional weights are commonly used throughout the industry and almost always used for passenger weights. These weights vary depending on the type of flight, the length of flight and the geographical area of operation. For example a scheduled flight within Europe might typically be 13Kg per hold bag, 88Kg per male passenger, 70Kg per female passenger, and 35 Kg per child. In circumstances where it is impractical or undesirable to differentiate the number of male and female passengers, a standard adult weight of 84Kg can be used. Holiday charter flights use weights slightly lower than these.

Perhaps surprisingly these passenger weights include hand (or carry on) baggage.

Averaged out, it is argued and generaly accepted that whilst some passengers and carry on will be heavier, some will also be lighter. Whilst it is unlikley to generate a precise number, the margin of error falls within the safety margins inherent in the manufacturers calculations.

You raise an interesting point concerning the situation where greater quantities of carry on baggage is now being encouraged by some airlines. This encouragement takes the form of either a hold baggage (penalty) charge, or the removal of carry on weight restrictions. Whilst I would take issue with the concept that many people could drag 30Kg of hand baggage on board (with the exception of Hajj flights!) It is certainly true that the actual mass of cabin baggage probably exceeds that being allowed for in most standard calculations. However if you assume 12Kg on the (average) very high side. 5 kg is already allowed for in the notional figures so the excess (on a 757 sized aircraft) would still only amount to 1400kg. Distributed throughout the cabin, (and volume or hatbin constraints would naturally dictate this.) That really isn't as much as it sounds.

Whilst I appreciate your argument that airlines may be missing how much weight passengers are carrying on board, it has to be sensibly tempered with the fact that volume constraints would prevent the carriage of ridiculously large amounts. I often travel with a very large 81 litre suitcase (which is obviously checked in.) Crammed full of clothes, toiletries, and the charging paraphenalia for my computers and phones etc, and coupled with the fact the empty weight of the case is some 6Kg, the total rarely exceeds 23Kg, and that would be impossible to store onboard in the normal course of events. Even where passengers do take large cabin bags on board, the volume constraints will eventually result in any excess being consigned to the hold, where it then assumes a notional weight as described above.

In unusual situations (perhaps carrying 200 members of the womens international federation of shot putters, together with their personal collection of shot putts,) it would be relevant to use actual weights or to make appropriate adjustments to the loadsheet.

The whole mass balance scenario tends to become more critical, and more of an issue in smaller aircraft where the excess tolerance is not so great, and the numbers involved do not allow for an average figure to be used on so many occassions.

[Hartington]

I don't think I'd had my carry on baggage weighed for years on any airline until last week when they weighed me, my suitcase and my hand baggage. Actually, I have to admit the flight was on an Islander and it even made me feel quite good that they did it.

[frnikolai]

Thank you everyone for you're replies, I just got worried as from an internal (Bournemouth to Prestwick) flight - everyone had checked in online. And I am very sure not all bags were 10 kilos. Mine was very light as I am here for 2 nights - but others looked heavier! I am sure I saw at Stansted scales at security to weigh carry-ons.

Thanks,
Nikolai

P.S

I have never been weighed at check-in although I am not worried - it could be embarrassing for some.

[Final 3 Greens]

Can you ever remember being weighed at check-in?

Monarch Airlines, Luton, 1979 - aircraft 1-11.

The only time ever :eek:

[BOFH]

I looked it up - Llandow, Avro Tudor, Fairflight Ltd, run by the much-admired (and feared) AVM Don Bennett. 12th March 1950. [0]

Apparently the CofG could have been > 100" out - Fairflight was prosecuted for being > 7". Very laissez-faire attitude to luggage stowage back then.

Bealzebub
a standard adult weight of 84Kg can be used

I stand corrected. That's pretty generous, if I don't exercise or drink, I can slim down to that pretty easily :} .

BOFH

[0] Macarthur Job: Air Disaster Volume 4, I am still hanging out for Volume 5

[PAXboy]

Every couple of years, there is a weighing programme. I recall being in South Africa when there was voluntary weighing of pax. Sine this was for a regular 737 type internal flight of 1,000 miles I naturally picked up the leaflet.

The SA airports were weighing pax (self-selected) across a range of flights to see what their weights were. This information was then sold to other airlines to enable them to update their average weights. The leaflet said that this was done around the world at various times to measure long term trends in various populations.

I stood on the scale and my weight was not visible to anyone, the computer simple noted it. My bags were weighed as normal.

It is not just the the citizens of the USA that are large and carry lots of bags, travelled by air in Africa ?? :oh:

[TSR2]

A question for the professionals.

In the calculation of take-off speeds for say a B737/A320 size aircraft, how critical is the accuracy of the total weight of passengers and bags. Also, is the weight of the crew and their bags ever taken into consideration as some crew seem to take more baggage than I do even on a short haul flight.

[Bealzebub]

First of all "critical" is a word with a number of definitions and can be emotive. When it comes to aircraft performance, there are aspects that can indeed be critical (extremely important), and certainly most aspects of mass/balance calculations have a high to very high degree of importance. When approaching a defined limit there is clearly a degree of criticality applicable. Nevetheless there are safety margins designed into most manufacturers and regulators performance calculations, and these margins in part allow for the "error factor" that may be inherent in day to day operations.

As has already been discussed in this thread, for most large passenger aircraft operations, the type of operation allows for the use of "notional" weights. These weights may well be individualy erroneous, but averaged out over a relatively large number of units should result in acceptable error margins. Ideally we would strive for the most accurate figure possible, but practically that is often not realistic.

To try and answer your question (I don't have figures for an A320/1) as it might apply to a Boeing 757 with 220 seats. If you assume a full flight with a 60/40 mix of males/females and 10% of that total are children between ages 2 and 12. There are a total of 230 bags. You would using notional weights arrive at a total payload of 19,744kg. If you used average adult weights your payload would be 20,392kg On a typical 4 hour flight with a fuel load of around 20,000kg this would give a take of weight of around 100,400kg. As a matter of interest this is still only 88% of the maximum permitted take off weight, or the maximum permitted payload.

If you had subsequently discovered an error of 10% in the payload this would mean that each of your adult passengers had actually weighed in at 93kg and all of them had bags averaging 14.5kg, you would actually be carrying a payload of 22,430kg and a take off weight of 102,440kg. The difference to your take off and reference speeds would be about 2kts.(2.3 MPH.)

On the question of crew and their baggage. Crew are taken into account in the basic weight of the aircraft (APS= Aircraft Prepared for Service mass.) Again standard weights are used. Crew baggage (except carry on) is an additional figure to be added and here the option to use either notional weights or actual weights is applicable, however it is added on and taken into account.

I hope this helps understand the topic. As you will appreciate I have tried to simplify what is a very complex subject. Some of the figures I have used are in substitution of "how long is a piece of a string?" But they should provide some guidance on how an important calculation can be tailored to allow for guesstimate figures being employed.

[TSR2]

Many thanks for that clear and concise explanation. I won't pretend that I fully understand but at least it gives me an idea. Thanks for your time, much appreciated.

[Atlantean1963]

And they do keep up the research....

Three weeks ago I and my hand baggage were weighed together for a survey (post security) at WAW.

And they weren't telling the pax the results....:)

Best Regards,

Atlantean.