airliner actual weight vs GTOW?

Not sure how the DP happened.
 
Kinder said:
If you always use the wrong weight for an average weight than yes your results will be consistent!
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Yes, they would be consistently off! As an example we flew BOM to FRA. We consistently over burned on that flight to the point we had a few diverts. We have the option on a flight that severely over burns or can’t make the planned cruise altitude to request a load audit. Turned out the station manager was running his own little cargo operation with a couple of extra cargo cans and the check in agents would wave the overweight baggage fees for a small donation. That meant the overweight bags did not get accounted for properly.
If you’re flying 8 plus hour flights you know if the weights are accurate or not. They are very good.
 
Dan Thomas said:
But how sensitive is it? I have never seen any aircraft oleo that didn't have some stickiness to it, and the large airplanes I worked on sure wouldn't respond to the weight change of one or two people. Maybe not even ten people.
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I have flown most large airliners both Boeing and Airbus. None had the ability to generate their own weight from the struts or otherwise. I believe it was an option on the MD11 but worked so poorly they stopped using it.
 
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Kinder said:
According to the CDC 74% of adults in the country are overweight
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Your argument is flawed because you're presuming the basis for 'proper weight' is the average weight.

Per the NIH, at https://www.nhlbi.nih.gov/health/educational/lose_wt/BMI/bmi_tbl.htm you will see that proper acceptable weight (BMI of < 25) you are only supposed to be at about 200 if you are 6' 3 or taller.

So anybody less than 6' 3 weighing 200lbs would be both, average weight AND part of the 74% that is overweight.
 
I was sitting in my usual window seat during boarding when someone got on board, stuffed their oversized bag into overhead storage, and plopped down into the middle seat next to me. They proceeded to explain that "The Government" and airlines were conspiring to force people to carry on heavy bags (by charging to check them) and store them overhead, making airplanes 'top heavy' and thus causing more crashes. It was clear from their manifesto description that the goal was more crashes, but i wasn't about to dig in to find out why the conspirators wanted more. Thankfully it was not a full flight and they moved to another seat before takeoff.

Nauga,
who wonders if we've met
 
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Kinder said:
After US airways flight 5481, which crashed January 8, 2003, the FAA ordered 15 regional airlines to survey passenger weight. The survey showed average passenger weight with carry-on bag was 26 pounds heavier than the standard so the FAA raised passenger weight by 10 pounds. What? Only 10 lb? WTF
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Repost
 
SkyChaser said:
Where are you getting that info? I was pretty sure that they raised it from 170/average person to 200/average person?
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In Kinders defense he did say average male weighed more than 200 with carry on. I'm sure most read that as person. He's probably right. Us fatasses here in Michigan probably average 275 with carry on for the men.

https://www.healthline.com/health/mens-health/average-weight-for-men says:

How much does the average American man weigh?

The average American man 20 years old and up weighs 197.9 poundsTrusted Source. The average waist circumference is 40.2 inches, and the average height is just over 5 feet 9 inches (about 69.1 inches) tall.
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That doesn't include carry on.
 
Kinder said:
Repost
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I'm sure you are aware that was 20 years ago, and since that accident the average weights program was substantially changed, and has gone several revisions.

Also, airlines monitor aircraft weights versus fuel consumption. If weights are off, it will show up here.
 
Jeff767 said:
If you’re flying 8 plus hour flights you know if the weights are accurate or not. They are very good.
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I'm new to this long haul stuff, but I've been blown away by how accurate the fuel plans are. 15+ hour legs and and damned near 300,000 pounds of burn and we're commonly within just a few hundred pounds at touchdown.
 
Doc Holliday said:
I'm sure you are aware that was 20 years ago, and since that accident the average weights program was substantially changed, and has gone several revisions.

Also, airlines monitor aircraft weights versus fuel consumption. If weights are off, it will show up here.
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Yes and we are heavier than ever
 
Jeff767 said:
I have flown most large airliners both Boeing and Airbus. None had the ability to generate their own weight from the struts or otherwise. I believe it was an option on the MD11 but worked so poorly they stopped using it.
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I can imagine it would work poorly. Sticky struts would do that.

Many years ago I sold truck parts. Some logging trucks used onboard scales to weigh the log bunks while loading so they could get as much on board as was legal. Those scales used wide, flat steel chambers that had diaphragms in them. They had a small valve on them, too. Air from the truck's air brake supply was fed into those scales, and they would lift the bunks off their pivots until their valve opened and prevented further lift. There was little or no friction involved. As the load increased, it took more air pressure to support it, and the pressure was shown on gauges in the cab, calibrated in pounds. They were pretty accurate. I would imagine that they have been replaced with electronic load cells by now.
 
median would probably be a better metric to use. Mean is just going to get thrown off by the large scatter in the US population, given our multi-ethnic nature.
 
Or more maybe.. what *most* people weigh. However the current system seems to work so "don't fix it" if it ain't broken sort of thing
 
Tantalum said:
Or more maybe.. what *most* people weigh. However the current system seems to work so "don't fix it" if it ain't broken sort of thing
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You mean the mode? Careful, that would be problematic in a multi-mode distribution. You know, populations with established dimorphism....like humans. Given there's more females than males, you can easily grab the the higher count but left-bound mode, and exacerbate the undercounting concern. Thus, median would be a better predictor of the load in any given flight for a multi-polar population.
 
hindsight2020 said:
Thus, median would be a better predictor of the load in any given flight for a multi-polar population.
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Not sure this is true. While median is an outlier-resistant estimator, the whole point here is that we're computing expected overall sample sum, including those outliers. The population mean is the unbiased estimator for that sampled mean.

Imagine a population where 90% of people weigh 200lbs and 10% weigh 300lbs. The median would of course be 200, and that is useful for thinking about the population. When you fill a plane with 100 people, though, those outliers show up! The sum of the weights will be n*(mean weight), not n*(median weight).

The best approach would be to take the total distribution of passenger weights and compute the 50th (or whatever, pick 99th percentile to be safe) percentile sum of n samples from that distribution, where n is the number of passengers. By central limit theorem this median will tend to n*population mean as n increases.
 
Eric Pauley said:
Imagine a population where 90% of people weigh 200lbs and 10% weigh 300lbs. The median would of course be 200, and that is useful for thinking about the population. When you fill a plane with 100 people, though, those outliers show up! The sum of the weights will be n*(mean weight), not n*(median weight).
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Noted, but that's not the weight population distribution of US passengers. Even a symmetric unipolar mode distribution would be more accurate than a 90/10 hypothetical. To say nothing of the multi-modal population of co-ed pax load representative of most airline flights. My vote is still go with the median.
 
hindsight2020 said:
Noted, but that's not the weight population distribution of US passengers. Even a symmetric unipolar mode distribution would be more accurate than a 90/10 hypothetical. To say nothing of the multi-modal population of co-ed pax load representative of most airline flights. My vote is still go with the median.
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The point is that the median is not the correct estimator. The hypothetical distribution is just an example to show that. When estimating the actual sum of passenger weights the mean passenger weight is the correct number to use, not the median.
 
It's clear some people think they understand statistics.

Airline passengers are neither all male nor all adult. But the average American adult weight is 181#. Add some kids and some carry-on bags, Bada bing, bada boom.
 
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Man if I was booted for weight limits after I boarded I would be one ****ed of passenger. Never been heard of that on commercial flights
 
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