Originally Posted by
seagar
While this may be a question more correctly asked to someone other than a pilot, I will give it a try here.
I flew round trip a few weeks ago and on the outbound probably had 30% children. On the return, I didn't see one child and most were men that seem to all average 200+ pounds. It got me to thinking about aircraft design and weight maximums.
Over the years, planes have gone from 30 to 33 rows or from 8 abreast to nine abreast in coach. I know the planes were designed to carry a specific weight and now have an additional 15 to 30 passengers/seats. I also believe that there is an average weight applied per passenger, which according to the government since we are almost all obese, probably isn't accurate at take-off. My question is at what point do the planes reach there safety limits vs. CFO's economic interest and does this even concern any of you?
The total weight of 200 people on this airplane and then 200 people on that airplane will be very similar unless it's mostly football players or kids. Adjustments for kids under a certain age are considered, as are charters where we carry football teams.
The tolerances used in figuring passenger and cargo weight are pretty lenient, and the various maximum weights, like ramp, taxi, takeoff and landing weights all are on the conservative side. The airplane maker's limits may be exceed in actual operation, but design limits, which include safety factors, will rarely if ever be exceeded.
So, to answer your question, the number of times a safety limit is exceeded is statistically insignificant. It doesn't exactly answer it because it's impossible to define it as a point, but I understand what you're asking.
Years ago, I flew a short hop from ORD to DTW in a 757. After we took off, the F/A came up and told us he had reported the pax as about 50 less than actual, so that put our actual takeoff weight about 10,000 pounds over what we'd calculated our takeoff speeds, single-engine climb performance, and fuel burn by. Since our fuel burn would be about 5,000 pounds for this flight, we ended up landing at a higher calculated weight than we took of at. It was pretty operationally insignificant because we were at least 40,000 pounds under any maximum weight limits in the first place, but I remember it was kind of a lot of pull on the stick to get the nose up on takeoff.
Bottom line though is that no matter how much The Upper Management Breakfast Club wants to stuff an airplane with profit-widgets, they have to stay within the FAR limits. so their economic interests don't scare me. There are plenty of other things about them that scare me, though.
By the way, on my random drug test this morning, they found traces of recent FlyerTalk usage.
FAB