tcraig

Was on AS 678 on June 14, SEA-DEN, a full flight (details offered in case anyone wants to look it up). After boarding, they asked for 20 volunteers for "weight and balance issues" offering VDB. About a dozen took up the offer then they offloaded bags. I assume the issue was a max weight issue.

This raises several questions in my mind. How could a 1000 mile leg on a 737 (even if it was a 900) departing on a cool evening from sea level with a long runway end up overweight that much? Could they have been carrying a huge amount of fish on ice or gold bars or something? How could they have not known ahead of time they needed volunteers? Is some cargo profitable enough that offloading 20 people can be a net win?

This flight ended up 2 hours late because the original aircraft had a mechanical issue (or so we were told) and we eventually were given a different aircraft. Could the backup aircraft have had some issues that didn't affect the airworthiness but might have impacted the allowed maximum weight? Does that ever happen?

The situation just doesn't compute. If it were some combination of a long leg, "hot and high", a short runway, or something like that, I'd understand. This I don't understand. Any ideas?

sltlyamusd

Did the flight take off full? It looks like the flight was scheduled as a 737-900, it went mechanical, and they swapped aircraft to a 737-800. The -900 has 172 or 181 seats and the -800 has 157 or 163 seats (depending on whether it is reconfigured yet). This would be the mostly likely explanation to me for needing to suddenly offload around 20 pax.

MonThruThurs

Only reason I can think of is that there was some heavy special cargo that provided more revenue than pax.

tcraig

Good question. We were scheduled on a 900 and I thought we were swapped to an 800. When I noticed that at the gate, I waited for the preboard chaos to ensue, but it didn't. They did not ask for volunteers before boarding that I know of (which I thought was odd) nor do any seat swapping that I could see. They boarded the airplane full then a dozen people left the airplane and the doors closed and we went out with empty seats and eventually missing bags.

I had an upgrade, so I had a pretty good view of what was going on. Like I said, I can't quite sort out what happened or why.

WhIteSidE

To the best of my knowledge, all of the 737-NG can do 1000 miles "if the doors close" ... that is, on that segment it should have been able to carry about anything they could fit inside.

beckoa

Wirelessly posted (beckoa's BB: Mozilla/5.0 (BlackBerry; U; BlackBerry 9810; en-US) AppleWebKit/534.11+ (KHTML, like Gecko) Version/7.1.0.694 Mobile Safari/534.11+)

Possibly nonrevs or some folks rerouted who were going to misconnect in DEN?

tusphotog

If the plane you swapped with to had been fueled for a much, much longer flight (i.e. SEA-FLL, KOA or even DFW), chances are they'd be over max landing weight. To keep from delaying the flight even more, they probably didn't want to offload fuel.

Has nothing to do with getting the plane off the ground out of SEA (unless 34R is closed or something), but more on the landing side.

3Cforme

That might be plausible on a very short flight like SEA-PDX or SEA-GEG, but SEA-DEN is going to burn plenty of fuel to cover the difference between max take off weight and max landing weight.

MonThruThurs

Don't think so. The 73H can fly upwards of 7 hours at MTOW, so SEA - DEN should be no problem given the tradeoff between fuel and pax/cargo.

Copa, The 4 Longest 737 Flights In The World?

PDXPremier

VDB on AS....now that's a rare event these days (compared to DL or UA where it seems like almost every time you check-in, you get asked if you want to be put on the VDB list)....it's been since maybe the 90's or early 2000's that I got VDB on AS--what is the compensation these days?

seatrader1

I had similar back in April coming back from TUS to SEA. Due to a "weight imbalance" they were unable to load approx 60 checked bags. Those got loaded on a later US Air flight. My dad and I had 4 checked bags which none were loaded which two were golf clubs.

SOCguy

This (and I'm fairly confident that's exactly what happened here).

Example (fake numbers, not for a 737.):

Empty a/c (no pax or fuel) = 100,000 pounds.
Pax and cargo = 40,000 pounds.
Fuel = 30,000 pounds.
Fuel burn for flight = 20,000 pounds.

So, plane leaves at a weight of (100,000 + 40,000 + 30,000) 170,000 pounds.
En route, it burns off 20,000 pounds of fuel so when it arrives at its destination, its expected to land at 150,000 pounds.

BUT, the aircraft's maximum landing weight is 140,000 pounds. Guess what, you're now 10,000 pounds overweight out of your origin. This would be what we call "landing weight limited." Offloading fuel can be an incredibly time-consuming process, especially if we're talking many thousands of pounds.

enzian

5000 pounds of Copper River salmon that needed to get to Denver ASAP?

jackal

Can they just request to fly at a lower altitude--say, 20,000 feet--that burns more fuel than normal cruise and thus get down below max landing weight?

johnp012001

Um, in that example the plane would have to land with zero fuel!