Emergency descents: can you feel them?
 

Hello all. It has been a while since I posted here. During a "routine" descent, you/the passengers can feel the aircraft leaving the cruising altitude as the descent begins. But soon after, you adjust and stop noticing that you are descending. What I wanted to ask, and I expect there is no black-and-white answer, is at what descent rate would a passenger have a continuous feeling of descent? I imagine that, during an emergency descent in which the pilots pick up 5,000 feet per minute (more?), for the duration of that procedure the passengers would have a definite "sinking" feeling in their stomach? Am I correct? Thank you.

No you're not.

The human ear can feel acceleration, not speed. As long as the aircraft has a downwards acceleration you will feel like you're "sinking". As soon as the forces are equal to 0 (ie the speed of descent is constant) you will not feel anything. Your eyes might tell you that you are descending if you have the required visual references, but your ear can't, so if you're in cloud or can't see out, you wouldn't know once the speed of descent is steady.

It's correct that the ear can't detect steady speed, though of course it will recognise changes in pressure, particularly during the OP's emergency descent.

True, but that is not caused by the descent in itself but by a change of pressure. Therefore in answer to the question

The answer would be no, you would not feel 5000 fpm any more than 500 fpm. You would probably notice though as you say due to the pressure, and also due to the oxygen mask falling on your head :ooh:

Thank you for the replies. That is really interesting! Let's leave the oxygen masks and the panicking passengers out of it, I just want to talk about the actual sensation in the cabin.

CV, if you say that you cannot feel 5,000 ft per minute any more than 500 ft per minute, my next question is this: would the pilots accelerate the aircraft faster out of the cruising altitude when initiating an emergency descent than they would when starting a "normal" descent from the cruise?

You would also feel a rumble throughout the cabin due to the speedbrakes being fully extended for the emergency descent. You would know it was different, just from the sensations, regardless of the masks etc. Yes - we initiate the descent much quicker, the deck (cabin) angle will be steeper and you'll feel/hear the rumble of the speedbrakes.

During an Emergency Decent the pilots would descend to FL100 or MSA (whichever is higher).

They would do this by deploying the speed brake and accelerate to VMO/MMO (if structurally capable).

Initially, you will feel the decent and possibly some 'negative G' but as CV has already said, once the forces are equal, you will not notice it.

I just took the elevator from the 30th floor of my apartment block down to the 3rd floor. I felt the acceleration as we left the 30th floor, then I couldn't feel the descent, then I felt the deceleration as we stopped at the 3rd floor. Got it.

Thanks, gents! :ok:

When you are hot and high, you are in the same position as an emergency descent. Max speed, max speed brake, idle descent. I flew that today to get down (5000-6000fpm down). Rarely used (sometimes it makes sense) and often brings an ECAM caution on the bus because the cabin repressurisation can't keep up. I would suspect the key clue to a passenger would be some other event eg. call cabin crew to station, obvious loss of cabin px, smoke in cabin, combined with the above.