Primarily for general aviation discussion, but other aviation topics are also welcome.
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By A4 Pacific
#1839111
Gasbag wrote:Totally agree with @Trent 772.
374 pax all who’ve been stuffing themselves for 2 weeks. Handling agent gave us ACTUAL bag weights which took us 5 tonnes over max. Recalc with notional weights and we were several tonnes under max. Paperwork looked legal and we calculated performance on a far more realistic weight. Could still flex way down for take off as 330 is stunning!


We need to be careful here.

In the airline world (unlike the world of GA) there are a number of limiting take off weights.

One is the manufacturer’s MTOW, which in an A330 is not terribly heavy in the grand scheme of things? Around 240 tonnes or so? But there may be a different ‘certified’ weight specified by an operator, who can choose to have the aircraft ‘certified’/declared for a reduced weight, often for a reduced cost, perhaps with an option to later increase the MTOW for a fee and the cost of certification change. Some airlines which do not require a high MTOW choose to have a lower MTOW for that particular aircraft to reduce costs (Landing fees and air traffic control fees are MTOW based).

Then we come to WAT limited weights which depend largely on environmental factors, and performance limited weights which will depend on the specifics of the departure runway, weather and configuration/thrust selected.

All of these will be distilled into a Regulated Take Off Weight. The lowest of all of the above.

Certainly Gasbag was placed in an unusual situation. I can only presume that they are referring to ignoring the maximum certified weight for his/her specific airline? Rather than KNOWINGLY ignoring any of the others?

But this highlights the point of ‘normalisation of deviance’. Where rules/limits are knowingly broken for no good reason.

However these big jet ‘complications’ are all very different to the overwhelming majority of GA aircraft that will have one number for maximum take off weight.

It really is very simple!
Last edited by A4 Pacific on Fri Apr 09, 2021 7:06 am, edited 2 times in total.
By OhNoCB
#1839112
To add a little more to the airliner context - I fly 737s in work and we can get pretty close to the manufacturers MTOW. Not the performance limited one, nor an artificially reduced one, but the one in the airframe certification.

It is ABSOLUTELY something I believe that safety margins are eaten in to by the actual weight being different than the standard weights. Obviously some bags will be heavier and some lighter, same with pax, but I am pretty convinced that on an average day, if you got the scales out then we would be heavier than we are on paper, and therefore on a 'heavy' day, we would be over MTOW.
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By PeteSpencer
FLYER Club Member  FLYER Club Member
#1839116
ISTR at N LasVegas airport before a commercial jolly to Grand Canyon all the pax and their bags/cameras etc having to step on a set of bathroom types scales .

We were then walked out to the a/c and carefully sat in seats apparently to balance out the fatties No idea what Ac : about 9 seat high wing twin Rainbow Airlines .
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By skydriller
FLYER Club Member  FLYER Club Member
#1839119
Getting back to the GA world, is it not the case that the ubiquitous C152 flown with 2xadult males for training is generally overweight? ISTR in my flight training that mass/balance was "skimmed over" and that having actially tried doing a calculation one day I coukdnt get it to "work". It was only later when I went to the US that I realized I was right and so had a rather lovely young lady as my instructor to check me out on a C152 in Houston. 8)

Regards, SD..
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By Miscellaneous
#1839127
skydriller wrote:Getting back to the GA world, is it not the case that the ubiquitous C152 flown with 2xadult males for training is generally overweight?

Indeed, I'm rather surprised that the fact they were routinely flown overweight is not a wider known fact and that it appears there are some who think the certified MTOW equates to a design weight limit. :scratch:
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By MichaelP
FLYER Club Member  FLYER Club Member
#1839139
The Flyer video chat last night had an item on the new production Luscombe 8.
If you want an example of overweight temptation this is it.
The fortunate design attribute of this type is the lack of space for two 21st Century ‘normal’ adults.
I believe Cessna do not produce the 152 for its overweight problem. Rather the Cessna 172SP with its uneconomical 180hp fuel and oil burner as a two seater.

Until I taught in Thailand there was no weight and balance available for the Cessna 150 and 152 on the club.
I searched through the old FAA paperwork and found the old documents, and I used these. At least I had something.

One day at Biggin Hill a student came in and told his examiner that they would be 40lbs over weight. (Cessna 152). The examiner told him it was normal and they went flying.
In Canada there were no end of times we syphoned fuel out of Cessna 152 tanks to bring them within weight limits.
Then these students get their commercial jobs, and are pressured to fly overweight...

In Thailand the Cessna 152 was regularly flown at 150lbs over weight! The particular ‘instructor’ (he had no instructor rating anywhere) was big, and his Norwegian student was big. This ‘instructor’ took three Dutch people flying (Dutch size) with full tanks, and full flaps, in a Cessna 172F for a short hop to a crash.
That was the end of any of us teaching in Thailand.

Most aeroplanes we fly can fly with a certain amount of overweight, but their performances can be seriously degraded when the muck hits the fan.
There’s the insurance consideration... Then there’s your life.
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By Pete L
FLYER Club Member  FLYER Club Member
#1839141
The culture changed since someone was first foolish enough to give me a license 30 odd years ago.

My bet is the Isle of Wight PA28 crash concentrated minds and it was progressively taken more seriously in training. JAR probably did a bit. At Halton in the 2000s the C152s were flown within MTOW - with a degree of careful fuel planning for the next student. having a PA28 and if necessary a C182 helped :D

I've only flown an overloaded aircraft once and I don't intend to repeat the experience. Similarly getting on the back side of the drag curve with a very heavy rear seat passenger.

The other factor on my mind for C152s and PA28s is that although strong, most of them are old.

Edit: read the rest of the thread and at least opinions are stable if not the aircraft.
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By Miscellaneous
#1839145
Just to be clear I am not commenting on the rights, or wrongs of the practice. I am merely agreeing with @skydriller that 150/152s were routinely flown overweight during training. And that despite what some seem to think, exceeding the certified MTOW does not necessarily result in a smoking hole. :D
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By Pete L
FLYER Club Member  FLYER Club Member
#1839146
Another thought - should the Government's traffic light plan refer to Covid testing the package holiday traveller or weighing them post lockdown?

G-TAWG
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By Miscellaneous
#1839148
Pete L wrote:Another thought - should the Government's traffic light plan refer to Covid testing the package holiday traveller or weighing them post lockdown?

I'd suggest it would be better to fix the glitch in the system and reassess testing procedures to make sure similar can't happen again. :D
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By Rob P
#1839156
The irony of clicking one of the links in this thread about obese people and having it partially obscured by a KFC ad for a monster bucket of calories.

Rob P
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By A4 Pacific
#1839161
Miscellaneous wrote:Just to be clear I am not commenting on the rights, or wrongs of the practice. I am merely agreeing with @skydriller that 150/152s were routinely flown overweight during training. And that despite what some seem to think, exceeding the certified MTOW does not necessarily result in a smoking hole. :D


I’m not sure anyone here is suggesting it does. In fact quite the opposite. People have probably been making up their own numbers since the Wright brothers at Kittyhawk. Or even the Montgolfiers.

Hence the the normalisation of deviance, or “we don’t do it that way around here.” We know better. It’ll be fine.

To be fair, it probably won’t be catastrophic, and that’s precisely why it becomes so seductive. Where are the limits then? Why bother with limits at all? If it flies, it flies. Right?

But if one of the first things any investigation discovers is that the aircraft was known to be overweight, then the pilot(s) look like cowboys with some awkward questions to answer should they be fortunate/unfortunate enough to survive.

I imagine it could also invalidate your insurance?
Last edited by A4 Pacific on Fri Apr 09, 2021 10:25 am, edited 2 times in total.
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By Miscellaneous
#1839165
A4 Pacific wrote:I’m not sure anyone here is suggesting it does

Maybe a difference in interpretation? That's how I read some of the responses in light of the @SteveX's question.
A4 Pacific wrote:But if one of the first things any investigation discovers is that the aircraft was known to be overweight, then the pilot(s) look like cowboys with some awkward questions to answer should they be fortunate/unfortunate enough to survive.

I don't know the relevance to me simply stating fact?
Last edited by Miscellaneous on Fri Apr 09, 2021 10:25 am, edited 1 time in total.
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