Swiss A320 cabin pressure, "ATC refused descent request"
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Join Date: Mar 2000
Location: UK
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It is worth remembering it is a very big sky and a relatively small aircraft, so while you may create excitement if you do 'plunge' down unannounced, you are very unlikely to actually hit anything, and if you gotta go........................
Barker - remember we are looking at less than 20 seconds of 'useful consciousness' at those heights, and there will almost certainly be pax who have not masked up in that time. Also the effect of a 'rapid' will empty the lungs of most of the existing oxy, and the feed from the mask is going to be well diluted at that height plus the lack of a real positive pressure which as you will remember from the Ruddles-drinking course degrades the effect of oxygen - as you say we have no information as to how effective it is. Your 'monkey-swinging' crew could well be stacked in a heap in the forward galley, of course, if they risk moving around at the start
Barker - remember we are looking at less than 20 seconds of 'useful consciousness' at those heights, and there will almost certainly be pax who have not masked up in that time. Also the effect of a 'rapid' will empty the lungs of most of the existing oxy, and the feed from the mask is going to be well diluted at that height plus the lack of a real positive pressure which as you will remember from the Ruddles-drinking course degrades the effect of oxygen - as you say we have no information as to how effective it is. Your 'monkey-swinging' crew could well be stacked in a heap in the forward galley, of course, if they risk moving around at the start
Join Date: Jun 2001
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So here we are at 39000' and the ever vigilant FO brings to your attention the cabin vsi. The cabin alt is just over 8000' but has a roc of 200'/min, the outflow valve appears more open than normal, checklists are followed with no appreciable effect so that, after 5 minutes, the cabin is now at 9000'. You have no choice, you have to descend, but you DO NOT yet have an emergency.
Asking ATC for descent since you have a pressurisation issue is the sensible thing to do, it would be foolish to get into the more marginal procedure of an emergency descent if there is no need to. Why wait for the inevitable and place oneself in the more dangerous situation simply to satisfy ATC.
As has been previously stated, the commander of the aircraft can override ANY ATC instruction if he believes that instruction compromises the safety of his aircraft, common sense please, if a pilot states that he has a pressurisation problem why compound that problem by forcing him to declare a MAYDAY?
Asking ATC for descent since you have a pressurisation issue is the sensible thing to do, it would be foolish to get into the more marginal procedure of an emergency descent if there is no need to. Why wait for the inevitable and place oneself in the more dangerous situation simply to satisfy ATC.
As has been previously stated, the commander of the aircraft can override ANY ATC instruction if he believes that instruction compromises the safety of his aircraft, common sense please, if a pilot states that he has a pressurisation problem why compound that problem by forcing him to declare a MAYDAY?
Last edited by Bengerman; 24th Sep 2013 at 21:27.
