Cabin pressure – how is it controlled?

[Mikeact]

I’ve repeated this question on here as it wasn’t picked up in the daily chat and I would like an answer. I just happened to be on BA but it could of course be any airline.

‘Coming back into Heathrow last night on final approach, my ears really started to play up due to the cabin pressure. We just seemed to be gliding along quietly and I couldn’t wait to get down, and it wasn’t just me. I’m interested to know if the flight deck need to keep their eye on the optimal pressure or is it automatically controlled somehow ?
It surely can’t be that difficult this day and age to ensure it’s as comfortable as possible for all.’

[0 post]

Mike it’s usually automatic. Modern aeroplanes usually have a max cabin alt of around 6000′, older ones like the 747, 8000′. As you start to descend the automatics go into a different mode and calculates what your elevation will be at landing.

The cabin altitude gradually decreases as you descend as automatic outflow valves dump more air coming into the cabin from the pressurisation system. As you touch down the pressures are equal and the outflow valves are fully open.

So, the pilots shouldn’t have had to fiddle with anything but if there had been something wrong with the automatics and they were, then you’d probably have detected something with your ears sooner.