airliner actual weight vs GTOW?

Kinder said:
All I was saying was that the FAA average male weight with carry on baggage at 200 lbs is unrealistic
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All I’m saying is you have no basis to claim that 200 is unreasonable or to assert that using 200 for an average is an example of the industry ignoring the truth and airplanes flying overweight.

Guess we will just have to disagree.
 
Kinder said:
average weight for a male with his carry on is now 200 lb. HA! I’ll bet it’s a lot more than that. I would like to see every one weighed at the gate and your fare adjusted accordingly!
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At the airline I worked at all passengers (not just males) that were 13 or older "weighed" 200 pounds. For those 12 and under they "weighed" 100 pounds. As others have said just because you did C and D checks on 747s doesn't make you an expert on Weight & Balance issues.
 
jayhawk74 said:
At the airline I worked at all passengers (not just males) that were 13 or older "weighed" 200 pounds. For those 12 and under they "weighed" 100 pounds. As others have said just because you did C and D checks on 747s doesn't make you an expert on Weight & Balance issues.
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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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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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“based on data sample A we have determined the proper correction factor to be B, so we decided to use epsilon”
 
Greg Bockelman said:
You are talking to a lot of airline pilots, dude. They know what they are talking about.[/QUOTE
I suspect that if the FAA raised up the passenger weight to reality the airlines would have to remove some seats and we would get our legroom back
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@Kinder in regards to legroom that little experiment has popped up occasionally over the last decades after deregulation at all of the legacy airlines. Universally the market does not respond well and the product offering is removed. In general the customer base is not willing to spend the extra pinch for a more roomy seat. There are exceptions to this and guess what… we have airplanes with big comfortable lay flat seats to service those markets. I’m sure you are willing to spend the money but most are not and the airlines have to structure the product to meet demand.

To put this in perspective the small fleet of premium cabin aircraft my current employer operates seat approximately half as many people. The tickets average many thousands of dollars for a domestic transcontinental flight. That same route serviced by a meat wagon with all the noses up the butthole ahead tickets are typically measured by hundreds not thousands. We have hundreds of meat wagons and a very small number of premium low density birds. It’s all driven by market demand.
 
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Some of the concepts here have roots in antiquity.

Calculating available power and performance via graphs are not new tasks.

IIRC - The C-54 required a 100 ft/min rate of climb with 1 engine inoperative.

That is pretty small !
 
Craig said:
Most big aircraft have the capability to self weigh via gear strut pneumatic pressures or strain gauges within the gear assemblies. I know the combat aircraft I work on has a reading that I can access as a maintenance guy, that shows current weight of the aircraft, no matter the load on it. If we are doing a defuel or certain refuel operations, I can watch the a/c weight change as the fuel load changes.
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I'm not saying it doesn't exist for large airplanes, but I've flown quite a few, and none of them display aircraft weight in the cockpit based on a strut gauge. All of them have been pretty much the same. The plane knows how much fuel it has on board (and how much that weighs), and we input the ZFW from planning into the FMS. A little magic happens, and voila, the plane knows how much it weighs.
 
Dan: It's good enough that we can't truncate fuel load number in our release data anymore....

Sluggo: Ours doesn't show in the cockpit, but on our maintenance computers we use for checking service levels. I assume that if one got deep enough into cockpit displays, one would find it. I've never looked, as I've always worked off the external computer system
 
Kritchlow said:
Yea, you really don’t understand the system. It’s all on the up & up. No looking the other way required.

ETA: now they break the peeps into zones, but several years back we just gave the number of peeps, and the computer assumed even distribution for balance purposes. As far as I know this is still approved, but now we break it into 2-3 sections to improve efficiency.
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Efficiency how? This happened on a flight I took a few days ago. SWA 737/800. First leg 63 pax, PDX-SMF. They made us spread into 3 zones. Second leg 58 pax, SMF-SBA. They made some occupy the middle zone, but not the back one. Zones were marked with blue lights. I was wondering is that a CG thing or about the efficiency of the cabin crew.
 
Yes, it’s all about the CG. The 800, with its longer fuselage (therefore longer moment arms) when lightly loaded, needs to have passengers arranged into zones, (which can also be affected by the cargo bay loads) to keep the CG within limits. A full or near-full 800 isn’t nearly as affected since the “zones” are already fully loaded (or close to), therefore evenly distributed. A 700 with its shorter fuselage isn’t affected by this consideration.
 
Tarheelpilot said:
All I’m saying is you have no basis to claim that 200 is unreasonable or to assert that using 200 for an average is an example of the industry ignoring the truth and airplanes flying overweight.

Guess we will just have to disagree.
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Not agreeing with either side, but a quick Google came up with

How much does the average American man weigh? The average American man 20 years old and up weighs 197.9 pounds .
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https://news.gallup.com/poll/328241/americans-average-weight-holds-steady-2020.aspx

The amount that Americans say they weigh also has not changed, averaging 181 pounds among all U.S. adults. Men report being about 20 pounds heavier than that, averaging 200 pounds, while women say they are about 20 pounds lighter than the overall average, at 162 pounds.
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And watching people try to put their bags in the overhead bins, I would guess that most are around at least 20 - 25 pounds
 
To the OP’s question:

There’s a ton of possible reasons for what you described. Without being there to know the details regarding weather, departure/destination runways, fuel, cargo, and all, it’s impossible to say for sure. Here’s a few thoughts though:

- Performance considerations for weather, runway length, fuel, and so on have been mentioned already and need no further explanation. I will add though that when it comes to this kind of flying, most already razor thin performance numbers aren’t based on things going right, but rather having sufficient margin in case of problems, like an engine failure. Sometimes getting a new ATIS where the temperature is now 2C higher can make the difference.

- That deadheading crew member likely HAD to be on the flight or, more appropriately, had to get to where you were going to operate another flight, usually as a reserve or reassigned pilot. This is often called “operational recovery” and it’s staggering how seemingly unrelated events can domino. A pilot with food poisoning in Wichita can literally cause a flight from Meridian to Hattiesburg, MS to cancel. Since it’s imperative to stop the bleeding, that pilot was going on that flight even if they had to kick off a passenger. Saying the word “overweight” may have been the gate agent trying to diplomatically open up a seat. Passengers don’t react well to, “Hey, he’s going and you’re not, get up.”

- It’s very difficult and time consuming to explain to passengers how and why the plane is out of CG, but pretty much everyone understands the basic idea that things that float or fly can be too heavy to work right. Sometimes gate agents and flight crews say “overweight” when they really mean CG, but don’t have the time or desire to explain it. I’ve had gate agents not understand this before too. Talking about CG gets an argument, but the second the word ‘overweight’ gets used, they get helpful and agreeable again. Go figure.

- Cargo can be designated as some variation of must-fly too. If that’s the case, ops may boot a passenger, depending on the airline. Priority cargo happens a lot with spare parts or if a group of bags misses their original flight and the airline is trying to get them back with the original passengers.

- Some airplanes are bad about weight and balance games while others aren’t. The CRJ-200 is a nose heavy pig where a cockpit jumpseater functionally “weighs” about 600 pounds, depending on the particular airplane. 200 extra pounds in the cockpit sometimes requires 400 pounds of ballast in the cargo bin between the engines. This was worst on short flights when the fuel created too forward of a CG for takeoff. More or less gas would be ok. Fuel loads shifting the CG is very real. Other times, it can be OK on CG without a jumpseater, but over expected landing weight. That’s when you move gate checked bags from the cargo hold to the cabin. Bags are part of standard passenger weights when in the cabin but count as additional weight in the cargo hold, so you move some of them into the cabin to get your “on paper” weight down. Technically, a passenger who gate checked a bag was having said bag counted twice for weight and balance anyway. So long as the number of cabin bags doesn’t exceed the number of passengers, you’re ok. The CRJ-700 on the other hand, was usually a USPS flat-rate box: if it fits, it ships. I still have not figured out how to get a Lear 45 out of CG, but being over weight can happen easily with trees and a wet runway for takeoff.



Bottom line, there’s no way for us to know why the flight crew did what they did. I will say there’s almost certainly a valid reason why that was the last option though.
 
luvflyin said:
Efficiency how? This happened on a flight I took a few days ago. SWA 737/800. First leg 63 pax, PDX-SMF. They made us spread into 3 zones. Second leg 58 pax, SMF-SBA. They made some occupy the middle zone, but not the back one. Zones were marked with blue lights. I was wondering is that a CG thing or about the efficiency of the cabin crew.
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Well, I always assumed it was a way to ensure folks were seated in the areas to give a more favorable fuel consumption… but that’s just my assumption.
 
RussR said:
@alanbreck , I'm somewhat wary that this response will get lost in the downward spiraling toilet bowl that this thread has become, but your question is a good one.

I think what it's important to realize is that large, transport-category aircraft are operating far closer to their limits/margins than, say, a 172 generally is. What I mean is this - when you takeoff in a 172 from a 5000 ft runway, the exact amount of weight you have on board, or the density altitude, or the humidity, or the flap setting, or the engine power, etc., just doesn't really matter too much. You have almost 10 times the runway needed in many scenarios. But if you instead operated regularly off of a 1000 ft runway with trees at the end, all of a sudden all those factors become much more critical. Instead of just briefly looking at the performance tables for max gross, you'd instead be calculating what your takeoff distance, climb speed, climb rate, all of that is at your actual weight. And then maybe you'd decide to take 10 fewer gallons or something like that.

When you add into that the additional safety factors that part 121 operators must comply with, like being able to stop on the runway during an aborted takeoff, or climb rate with an engine failure, then you see that lots of these airliners are often operating fairly close to the "limit". Granted, this is a "safety factored" limit, but a limit nonetheless. So a little difference in weight or temperature or whatever can cross that line, and that becomes a no-go until something is changed (like removing one passenger).
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Plus we do reduced power takeoffs to bring it even closer to the margins. With a “flex” takeoff the power changes quite drastically to preserve engine life if full power is not needed.
 
In the 90s I worked resolving data center operational problems all over the country. This seemed to always result with me catching the last departing flight of the day to my next destination. Often the gate agents were as worn out as I was, and I found a way for all of us to get a laugh that was sometimes beneficial for me.

The planes were almost never full. As I was showing my ticket and getting a boarding pass (yes, that was the way it worked back then), with a deadpan expression I would tell the agent "If you have an aft CG issue on this flight, I'm available to be moved up to first class."

It always got a smile and a chuckle, and occasionally produced a boarding pass in rows 1-4. No doubt the agents had heard that line before, but it was always fun to use.
 
Kritchlow said:
Well, I always assumed it was a way to ensure folks were seated in the areas to give a more favorable fuel consumption… but that’s just my assumption.
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I was wondering just that when you said efficient. Allan Cobb ‘s post #54 makes it seem like it’s needed to literally stay in the CG envelope. But it makes sense to me that getting a more fuel efficient CG would be a thing. I’m not arguing with you guys, just trying to learn stuff. My frame of reference is a bugsmasher brain that just knows aft CG is more efficient but less stable.[/USER]
 
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So as to be relevant to the thread.

This happened due to reasons beyond your or our ability to explain at this point in time. This is simply due to not having the facts that the decision makers were working with when the decision was made. Once you can provide all of those facts, we will be glad to explain what actually happened, vs what you perceived happened.

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On another note, I think the OP, if he chooses to stick around, will fit in perfectly fine here at POA.

"Tell me why?!?!"
"<maybe because of xyz>"
"I know more than any of you! How dare you answer my question in a way not to my liking?!?!"

I look forward to seeing his contributions to other threads he doesn't start.
 
guest user said:
So as to be relevant to the thread.

This happened due to reasons beyond your or our ability to explain at this point in time. This is simply due to not having the facts that the decision makers were working with when the decision was made. Once you can provide all of those facts, we will be glad to explain what actually happened, vs what you perceived happened.

-------------------

On another note, I think the OP, if he chooses to stick around, will fit in perfectly fine here at POA.

"Tell me why?!?!"
"<maybe because of xyz>"
"I know more than any of you! How dare you answer my question in a way not to my liking?!?!"

I look forward to seeing his contributions to other threads he doesn't start.
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you forgot to add "Here's what is really happening based upon my perception of the subject I know little to nothing about"......;)
 
That escalated!

The TLDR is it's a statistically reasonable average, reading the AC was interesting, thanks to whoever posted it. The question of does the plane actually way 486,582 lbs or 486,978? There's merit to that question. But reasonable statistics are used throughout the world, not just in dubious politics

I weigh about 185 lbs. Sometimes I travel with two laptops, two chargers, iPad, and heavy winter clothes in carry on. Sometimes I bring just myself and a light pack without laptop, iPad, etc. No, the plane does not know if my actual total weight that day is 193 or 197 lbs. Etc. But I don't think it's fair to say that because of that regulators are 'looking the other way' and planes are flying around outside of limitations
 
I can only imagine the suits and public outcry that would follow if pax were weighed at boarding!
 
Lindberg said:
Considering there will be women, and even children, plus people with no carry-on bags, on every flight, 200 lb is seeming like a very reasonable number.
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And there are those over 300 pounds and with a 100 pound carry on. :)

And one of the sources I quoted was based on self reporting. So how many people to you think fudged by 10 - 20 pounds?

But it seems to work, so it works.
 
luvflyin said:
There was a day when...
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Some airlines had a scale pad, flush with the floor and under a mat at the ticket wicket, with the scale visible only to the agent. People didn't know they were being weighed.
 
Passenger weights are based off NIH data. Baggage weights are based off actual bag weight surveys done by the airline. Winter and summer differences are based on heavier winter clothing.

Averages change based on the seating capacity of the aircraft. The larger the aircraft, the higher the average weight based on the smaller overhead bins in regional aircraft. Any valet checked bags are added to the baggage weight but with a smaller average.
 
Years ago I was flying somewhere with my mother-in-law. She was not a small woman, but not huge either--I would guess about 180-200 lbs.

We were getting on an Embraer 120 (30ish passenger turboprop), which she considered to be a "small airplane." It was clearly going to be very lightly loaded, no more than 6-8 passengers. At the door of the airplane, they were asking passenger weights, I'm sure more for balance than total weight.

Without hesitation, she reported her weight as 400 pounds.

As we sat down, I said, "Phyllis! There is no way you weight 400 pounds! Why did you say that?"

Her reply: "I'm not going to let them cut things too close for this little plane. I just gave them some margin for error."
 
Kevin Holbrook said:
Years ago I was flying somewhere with my mother-in-law. She was not a small woman, but not huge either--I would guess about 180-200 lbs.

We were getting on an Embraer 120 (30ish passenger turboprop), which she considered to be a "small airplane." It was clearly going to be very lightly loaded, no more than 6-8 passengers. At the door of the airplane, they were asking passenger weights, I'm sure more for balance than total weight.

Without hesitation, she reported her weight as 400 pounds.

As we sat down, I said, "Phyllis! There is no way you weight 400 pounds! Why did you say that?"

Her reply: "I'm not going to let them cut things too close for this little plane. I just gave them some margin for error."
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If it were truly for CG purposes, she did more harm than good.
 
According to the CDC 74% of adults in the country are overweight
 
I have flown a lot of long haul flights were errors in weights show up as increased or decreased fuel burn. Overall the weights are remarkable accurate. Errors generally are not with passengers weights.
 
Jeff767 said:
I have flown a lot of long haul flights were errors in weights show up as increased or decreased fuel burn. Overall the weights are remarkable accurate. Errors generally are not with passengers weights.
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If you always use the wrong weight for an average weight than yes your results will be consistent!
 
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