Question on the significance of a plane's weight

This is a long story so bear with me. On my way to Aruba I took a red eye on Jet Blue through Fort Lauderdale. The plane was 100% full. The plane was scheduled to land around 6 AM. However, as we're obviously nearing the airport the captain comes on the speaker and says due to fog we can't land in Fort Lauderdale and due to running low on fuel we have to land somewhere so he says he will be making a quick stop in Orlando to refuel and give the fog a chance to burn off.

We land in Orlando and sit there at a gate for at least and hour and the passengers are getting grumpy. Once in a while the captain says the fog still hasn't cleared in Orlando. Finally, after 90 minutes or so the captain says he is going to let us out to wait out the weather in Fort Lauderdale. We then dink around the Orlando airport for about four hours when they finally ask us to get back on the plane. Then we sit there another hour or so at the gate doing nothing. The passengers start getting restless again asking what the hell is going on? Finally, the captain says that several passengers chose to not get back on the plane and ended their journey by plane in Orlando. The two cities are not that far apart. The captain then explains that they are waiting on somebody to do some mathematical calculations due to the lighter weight of the plane.

Okay. I get that the plane is a little lighter due to some passengers not getting back on (I don't blame them). You would need to know a plane's weight to determine how fast to take off and land. However, can't they just assume some average weight per passenger and per bag? They knew exactly how many people left and how many bags they checked. What is so complicated about it? You would think calculations based on a plane's weight are done for every flight so should be automated.

Due to this math taking about two hours I missed my connection in Fort Lauderdale. Jet Blue said the hotels they had relationships with were booked so we had to pay about $400 out of pocket for two hotels rooms to make the flight to Aruba the next day. I might add Jet Blue was not very apologetic about this at all. I've been meaning to mail them the hotel bill for the layover but am expecting them to say, "Sorry, the weather is not our fault."

So, my question is why does it take two hours to do math on a plane that should weigh only 3% less or so?

p.s. I asked a few people in Fort Lauderdale when I finally got there if it was unusually foggy that day in the morning. They said not that they noticed. I say this as corroborating evidence that maybe this pilot was not at the top of his field.

Damn. that sounds like really bad customer service. Take no prisoners, give 'em hell.

I can see that disembarking those passengers would be a slow PITA, because of locating and disembarking their bags.
I guess they calculate and apply minimal carried fuel to pretty tight margins. Every cent counts and the time issues were possibly not costing them enough $$$ for them to give a damn.
I wonder if it was not so much that the calcs took a long time, but that it took them a long time to get sign off on extra expenditure. I.e they were bullshitting.

Get that claim in now!

For every minute the plane is in the
sky it burns fuel and loses weight.
How do they compensate for that
if the math is so important.

Quote: Wizard

However, can't they just assume some average weight per passenger and per bag? They knew exactly how many people left and how many bags they checked. What is so complicated about it? You would think calculations based on a plane's weight are done for every flight so should be automated.

I am pretty sure they do this as I was on a plane once where they were looking for minors. IIRC each adult was counted as 200lbs, and the bags were so close that they put a few on a twin plane running the same route. It got an annoying woman behind me worked up to the point she almost delayed the whole flight. I was steaming about her.

Bags were just weighed in. Probably had to manually go in and weigh what came off for some kind of report. Delay might have messed with flight crew hours or something they just did not tell you they had to fix up.

Sorry to hear about your flight issues and now you have me concerned. I am flying the redeye this week from Las Vegas to Fort Lauderdale.

I've seen this happen before, even experienced something similar. It seems that the major airlines do not leave the initial weight and balance calculations to the pilots - it is handled in the central office, and the pilots check the actual weight and balance against the plan.

I suspect that the lighter weight had more to do with the fuel, and the delay was getting someone in to the office to calculate what is essentially a unique, shorter, off route, possibly never calculated before flight, including calculating new maximum hold and divert fuel if when you got there you still couldn't land.

I can't see how just a couple of passengers alone would make a difference like that.

Quote: DRich

Sorry to hear about your flight issues and now you have me concerned. I am flying the redeye this week from Las Vegas to Fort Lauderdale.

I hope you don't get the same pilot I had. If so, volunteer your services if they need a mathematician.

Quote: Dalex64

I suspect that the lighter weight had more to do with the fuel, and the delay was getting someone in to the office to calculate what is essentially a unique, shorter, off route, possibly never calculated before flight, including calculating new maximum hold and divert fuel if when you got there you still couldn't land.

Good point; I hadn't thought of that. Just now I tried to search for a Jet Blue flight between Orlando and Fort Lauderdale and they just don't offer that route. You can't even do it through a connection. They are so close I don't see anybody doing such a short flight. However, the pilot did emphasize that the passengers that left in Orlando necessitated the mathematicians in the central office to redo all the math.

As someone who often counsels college students studying math, is there a profession that does these kinds of calculations for the aviation business? Had I known about it when I was graduating, I would have seriously looked into it.

Quote: Wizard

As someone who often counsels college students studying math, is there a profession that does these kinds of calculations for the aviation business? Had I known about it when I was graduating, I would have seriously looked into it.

Sounds like it would fall under aerospace engineer for the high level stuff.

If you are counseling college students, "Load Master" is what the USAF calls it IIRC. In AZ the owner of the house did this job. Big cargo planes, he had to figure where to put what to send to Iraq. Way back it was empty and they threw footballs around the plane.

Not sure of the reason, perhaps as mentioned because it was a route they don’t fly it may have taken longer to calculate. Who knows. But do not discount your original thought of incompetence. 18 months ago when I was connecting in LAX on my way to Vegas the plane was delayed (the final in a series of delays actually) because the people filling it with fuel had thought it was flying to Seattle so loaded a heap more than actually required. The extra weight made it unsafe to land in Vegas. They spent half an hour unloading fuel by which time the crew were out of hours and the flight was cancelled.