Do basses and/or flight cases expand or contract in airplanes?

Tight is no good. Get a looser fitting trunk or don't fly.

 

As long as the case is not sir tight, there should be no volumetric change in the case. air bags are a different matter.

 

The cargo hold is pressurized and heated. It’s not like your bass will be in the recess the landing gear retracts into.

 

True, but, it'll be in the luggage staging area for some time. Out on the tarmac for some time. Moreover, what stats do you have that demonstrate that airline's are "supposed to" maintain their cargo holds at given temperatures and pressures? I'd like to see that they don't shave pennies by short changing the air conditioning on the cargo hold. I've experienced them NOT air conditioning the passenger cabin until they're in the air.
If it was my bass, I'd expect huge differences between temperature, humidity, and pressure when flying. Moreover, not everything is within the airline's control.

 

The hold is where traveling pets are kept. Do the math.

What color is the case?

 

I don't know how many pets die each year during air travel. I do know it's not insignificant. Find the stats.

 

Interesting question. I know a groomer whose father is a pilot, and who is trained in the sciences.

 

Perhaps the "climate control" is the same that works in the cabin. But I am just speculating.

 

I disagree that you should pack loose. If something can move around in a flight case it can get damaged even if the case doesn't. You should pack tight but not too tight. I wouldn't worry about humidity changes. Sealed inside the bag and trunk there's not enough time for significant air exchange. Pressure? Only the inflatable bags would be affected, and since many trunk makers use them, it must not be a problem. Temperature? Again, only if the bass sits on the tarmac for many hours in the hot sun. KungFu, is that why you asked about color? I think this would happen very rarely, as a plane only makes money when it's in the air I heard, however, that several NY Phil basses were badly damaged when they sat in the hold of a landed plane for like a whole summer day and the climate control was off. Again, this has got to be very rare. Do make sure you insurance is paid up, and maybe read over your policy once more. Remember that no kind of travel is 100% safe. Not even walking. You just have to decide how much risk you are willing to bare.

 

I'm not sure the hold is actually climate controlled. Because the air is so thin at that altitude there is almost no heat loss. Also I've read that air friction on the fuselage actually has a slight warming effect.

 

The case is not completely sealed (unless you wrap it in twenty layers of polyethylene). The pressure inside the case and inside the bass body is the same as the outside, so this cannot cause damage.

Probably, you should worry about the work of the loaders, and not about the conditions in flight. All events of baggage damage that I know happened in the process of loading and unloading, and not on board the aircraft.

 

This actually happened to me with a guitar in an SKB case at the MSP airport. Half the plane's luggage showed up at the baggage claim and the other half didn't. They eventually located the missing luggage out on a truck, I guess the driver just went to break instead of taking it where it needed to go first. The case looked like like it had quite a ride too.