Why do airlines gate check bags when there is still overhead space?

Question

On a recent flight, an airline employee (either gate agent or flight attendant) who had just stepped out of the plane told my family that there was no more room in the overhead compartments, and we needed to gate-check our bags. I asked if we could keep just one, but was told it was completely full. So we checked them, after stuffing everything we absolutely needed into my son's backpack and wife's purse.

As soon as we got onto the plane, we realized that there were plenty of empty overhead spaces, especially near the back where we were seated. The first employee had outright lied to us. I mentioned this to a flight attendant who said that the reason was just time based - once we got close enough to takeoff, they automatically started gate-checking carry-ons. We then noticed that passengers behind us in line still had their carry ons. So that didn't seem accurate either. So a 3rd attendant told us that it was solely weight based - the airplanes had to balance the amount of weight above and below the passenger compartment.

Is this accurate? Do airlines gate-check carry-ons because there is too much weight up top or none on the bottom? If so, how do they choose which and how many bags to check? If not, what reasons other than room would cause the airline to gate-check bags?

Answer 1

Out of first hand experience with this as a previous cabin crew, sometimes the cabin crew of a flight signal the ground agents about the overhead compartments being full in the middle of the boarding process, so to avoid possible delays if removing excess hand luggage from the cabin is needed, the ground agents will prohibit cabin luggage for the remaining passengers and check them in at the gate just to be in the safe side and to avoid delays.

The logic behind this makes a lot of sense actually, delays are extremely expensive to airlines (financially and reputation-wise). Plus, extra luggage in the cabin can lead to over filling overhead compartments which lead to safety related hazards, compartments will be full to the point it can be easily popped out open by turbulence, or luggage will fall down on seated passengers heads when opened by passengers.

Bottom line, this is not as bad as it seems if you look at the bigger picture, and remember checked-in luggage is a pain in the neck for airlines, so they are not doing it for fun :)

Answer 2

I suspect it is to speed up boarding.

Stowing and unstowing bags takes a lot of time and they can take up quite a bit of room in the narrow aisles. So they are trying to get as much as possible checked in.

There is actually always enough room in cabin for the one bag per person. At worst some can be stowed under seats. So they'll let you take it if you insist enough. After all not everything may be checked in (electronics, anything with lithium batteries) or shouldn't be (anything fragile).

But please keep in mind that it indeed does slow down the boarding and disembarking, so often checking in will be more convenient for you and your fellow passengers as well, especially if you have some luggage checked in (and will have to wait for) anyway.

Answer 3

Sometimes airlines do require carry-on baggage to be checked for weight-and-balance reasons, but I've only ever heard of it being for front-to-back balance, usually in small commuter jets. Left-to-right balance is almost never an issue for airplanes: the dominant factor is the fuel tanks in the wings because of how far out from the center of gravity they are. I've never heard of top-to-bottom balance being an issue, simply because the top and bottom are both so close to the center of gravity.