Pressurisation Failure at FL350
You are the pilot flying a twin-engine turboprop at FL350 with 12 passengers and 2 cabin crew. The cabin altitude is climbing through 9,500 ft and the rate is increasing. The outflow valve position indicator shows fully open, and the cabin pressure controller has been selected to manual without effect. The oxygen masks have deployed automatically. Outside air temperature is −54 °C. The nearest suitable airport is 90 NM away with a 3,000 m runway and instrument approach; descent to 10,000 ft will take about 8 minutes at the planned rate. One passenger has a known heart condition and is anxious.
1. What is your immediate sequence of actions and why?
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This is a rapid depressurisation scenario. The immediate sequence is:
- Don oxygen masks and establish communications; confirm the mask is supplying oxygen (the bag inflates, and the pressure indicator shows flow).
- Establish crew coordination: pilot flying flies, pilot monitoring runs the checklist and communicates.
- Initiate an emergency descent to 10,000 ft or the minimum safe altitude, whichever is higher, at the maximum rate consistent with structural and speed limits; select appropriate thrust and speedbrake, and turn off the affected bleed or pressurisation system as the checklist directs.
- Squawk 7700 and declare an emergency with ATC, stating the nature of the emergency, your level, and intentions.
- Ensure passengers are on oxygen; the masks deploy automatically, but cabin crew must check for failures, especially the passenger with the heart condition.
- Once level at 10,000 ft, assess whether the pressurisation can be restored; if not, plan a diversion to the nearest suitable airport.
The priority order is oxygen, descent, communication, and only then diagnosis. At FL350 the time of useful consciousness is very short, so the mask goes on before anything else.
2. How do you manage the passenger with the heart condition and the cabin crew during the descent?
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The passenger is at risk from hypoxia, anxiety, and the physiological stress of a rapid descent. Actions:
- Confirm the passenger is receiving oxygen and that the mask is functioning; if the mask is not delivering, provide a portable oxygen bottle.
- Reassure the passenger and keep them seated with the belt fastened; anxiety increases oxygen demand and heart rate.
- Have a cabin crew member stay with the passenger if staffing allows, and monitor breathing and consciousness.
- Consider requesting medical advice on the ground and, if the condition deteriorates, declare a medical emergency and request priority handling and an ambulance on arrival.
Cabin crew management:
- Give clear, calm instructions over the PA and to the cabin crew: we are descending, masks are on, stay seated, report any passenger in difficulty.
- Have the cabin crew secure the cabin and report readiness before landing.
- Keep the flight deck informed of the passenger's condition so the diversion decision accounts for medical urgency.
The judgement is that the medical passenger may change the destination or the urgency of the approach, so the flight deck must stay informed rather than treating the depressurisation in isolation.