Originally Posted by
Joshb18
They didn’t say how they found out, I guess it’s plausible they knew before they took off, as someone said previously once some fuel had burned is when it became tail heavy.
They know as soon as the final load is calculated.
It doesn't have anything to do with fuel being burned. Fuel burn doesn't change the CG significantly. It is because, during deplaning, you will end up at a point where the entire front half is empty and the entire back half is still full. All airplanes are susceptible to the problem. It's more common in the stretched versions (737-900, A321, 757-300, 777-300, etc.) than the less-stretched versions.
You can mitigate the program by using a tail stand (the B727, DC9/MD80, etc. had built-in tail stands in the form of the aft stairs). If the tail stand isn't available then you unload the aft cargo hold before deplaning the passengers.