None,
Three types of issues can arise with pressurization systems.
The first is a 'pressurization problem'. This can be as simple as a bleed air source becoming unavailable. The worst case of a 'problem' might be a dual bleed fault. The outflow valve(s) will close and the cabin will climb at about 700-800 feet per minute.
The second is a 'rapid depressurization'. This could be caused by a fault in the pressurization system that drives the outflow valve to the open position. The cabin will climb rapidly and may be controllable in alternate auto modes or in the manual mode.
The third is an 'explosive depressurization' and would be caused by structural failure. The cabin will climb almost immediately to the aircraft altitude, fog will be present in the cockpit, years of accumulated dust will be flying around and probably a very loud 'bang' will have occurred. Of course the cabin is uncontrollable.
Each situation is unique and has different indications but pilot reponse should be the same. Get your O2 mask on, evaluate and act. My opinion is that in all situations where the cabin altitude is climbing the proper response is to start descending while you work through the issue and take appropriate actions.
best regards,
Bruce Waddington
Last edited by Bruce Waddington; 18th May 2009 at 03:56.