During a descent with blocked Eustachian tubes, the gas volume in the middle ear
A: Increase
B: Decreases
C: remains the same.
Answer in bob tait book is B.
Wouldn't it remain the same due to the volume of gas can not increase or decrease due to the tubes being blocked? I only ask because I had the same question in the CASA exam and I answered Decreases and I was marked wrong.
Thanks Gordon
Gidday Gordon
Assuming that the pressure in the middle ear and in the cockpit environment were equal at high altitude, with a blocked eustachian tube during a descent, the increasing ambient pressure pushes the eardrum inwards because the ambient air cannot flow into the middle ear to equalise the pressure. As the eardrum bulges inwards, the air tapped in the middle ear cavity is forced into a smaller volume.
It is the stress on the deformend eardrum that causes pain and hearing loss. I cannot agree with CASA if they marked that answer wrong.
Thanks Bob for your quick response. That's what I thought also. Maybe I did not read the CASA question fully.
