BBC | 飞机上换座选择什么时机比较好?

醉醺醺的乘客和满满的垃圾,或许是最令空乘人员烦恼的事情。但其实还有更加棘手的问题,那就是盗窃和换座。小小的换座涉及到舱位、重心分布等多种问题,可不是件小事情。

Tipsy passengers and overflowing bins might be some of the most grating annoyances flight attendants deal with. But what can be even worse are the four S's: stealing, sneaking, swiping and switching seats.

While it's not always a problem, it can definitely cause headaches for cabin crew.

“Most flight attendants don't mind if passengers change seats,” says Michael, a flight attendant for a major USA airline. Change seats in their own class, that is. Even then, there are some seats that are still off-limits.

This, of course, all depends on the airline — companies like Southwest Airlines and easyJet allow passengers to pick their seat once they start boarding. But in all other situations, passengers looking to sit somewhere else than they've been assigned can quickly cause chaos.

“It becomes a problem when a passenger wants to move to the exit row on the plane,” Michael says, describing those seats that have extra legroom. “Most airlines make people pay upwards of 50 extra bucks to sit in those seats and charge them when they book the ticket. It’s not fair for flight attendants to move or let people move to these seats when one or more paid extra to sit there. I personally don't let people sit there unless no one is sitting in the exit row.”

Extra legroom aside: Desiring to sit next to friends, family or coworkers is understandable. But swapping seats isn’t always that easy.

“Sometimes people will take it upon themselves to just have a seat where they want," Michael says. "It’s easier for us flight attendants to have them sit in their assigned seats until the person that was supposed to be in the seat they want shows up. When they come and see someone in their seat, it causes a more hectic boarding process, and the passengers are now trying to work things out and it causes a mess.”

But it's not always about wanting to sit next to your loved one. What about wanting to upgrade from coach to something more luxurious? If there is an empty seat and the upgrade list is empty, does that mean passengers from another section can relocate? Not so fast.

Sandwiched between economy class and either business class or first class is another price range tier often called premium economy class. Sometimes when flying aboard large aircraft on major airlines, there are noticeably different perks of wide, plush seats that transform into comfortable lie-flat beds. Beyond comfort, other bonuses may include early check-in, wider seats, upgraded meals or snacks, and sometimes even gratis cocktails or comfort amenities like a sleep mask or toothbrush. In smaller aircraft that aren’t flying long distances, the most common benefit — and for some travellers, the most obvious — is the added two to five inches of legroom. As always, the magic number depends upon the airline.

As for the dream of getting an upgrade? Most flight attendants will attest that first-class is usually full.

If there are any open seats, gate agents usually upgrade frequent flyers before boarding. Who gets the sought-after upgrades? Frequent flyers are the obvious first choice, followed by passengers who may have traded their seat for a voucher and upgrade on a later flight.

In addition to upgrades, there’s a science behind the weight distribution. This important factor is called weight and balance, and depending upon the plane size (especially smaller regional carriers) passengers may be asked to relocate, at least for takeoff. We asked a pilot to explain:

“All aeroplanes operate in an envelope of stability. To continuously stay in this envelope, from takeoff to touchdown, all weight and its location have to be accounted for,” says Darren Patterson, a pilot for a major US carrier. “If you were to attach a string to the top of the plane and dangle it, the center-of-gravity (CG) is the point where it is equally balanced. Just like two kids balancing on a see-saw,” he explains.

Passengers who think their own weight doesn’t make an impact on the flight may be surprised to learn otherwise.

“This CG continuously, yet slowly, moves throughout a flight as weight is shifted," says Patterson. "Even the movement of a single person walking in the aisle can be felt in the flight controls and very minor adjustments are made to keep the aircraft balanced. The largest loss of weight during any flight will be the fuel that is burned. So there are both a balanced starting point for takeoff and an ending point for landing. If both of these points are within that envelope you will always have a stable aeroplane.”

Have you ever noticed the flight attendants counting passengers before departure? Other times, some aircraft have software that intuitively reads distributed weight and compute the numbers electronically for takeoff, while other flight crews have to do it manually.

If you’ve ever been on a puddle jumper and had the pilots relocate passengers to another seat, that means weight needs to be distributed for safety’s sake. “The smaller the aeroplane, the more dramatic effect any shift in weight can have,” Patterson explains. “On a large, wide body aeroplane, a single person can move 10 rows of seats and the effect on the balance is negligible. Have that same person move just a few rows on a regional plane or turboprop and the effects are far more dramatic; possibly even exceeding the limits of the envelope."

Thanks to the convenience of technology, some airlines allow passengers to upgrade on the spot with a swipe of a credit card once onboard. Yes, the same little handheld device flight attendants use to charge you for your double gin and tonic has the ability to upgrade passengers right there.

The very best time to switch seats is online before getting to the airport, followed by meeting the ticketing or gate agents prior to boarding. When there are empty seats, it’s tempting to move, but there may be passengers still on their way to the aircraft. Once on the plane, the flight attendant is your final advocate — and we recommend you stick to the old adage, you catch more flies with honey than vinegar. In other words, request nicely, and you might just score the seat of your dreams. At least in coach.

Beth Blair is a former flight attendant and a freelance writer.