[tcrlaf]

I never said it wasn't crew initiated, I said the autopilot mode exists, and can be activated. Boeing required it be fitted years ago. Autopilot for aircraft having automatic descent function in the event of cabin depressurization US 6507776 B1 http://www.google.com/patents/US6507776 As I said, if the pilot/FO recognized Hypoxia, but too late to do more than dial down the altitude before incapacitation, that would explain the CONTROLLED but fast descent, which is my unfounded theory. Here is an example Emergency Action flow for an Emergency descent.

[Tzfat]

Apparently you do not know what a flow is. A flow is not “activated.” It is simply a series of steps. Each pilot has separate steps. It is the left seat pilot (not always the captain in an augmented crew with 3 or more pilots) that initiates the descent.

Every step is a crew step. NOTHING is automatic. And, you missed the first, most important step in the flow for EVERY airline on EVERY aircraft. Crew O2 On/100%. No hypoxia.

[Tzfat]

I said the autopilot mode exists, and can be activated.

Take a look at your flow diagram again. There is no autopilot "setting" for emergency descent. The left seat pilot is setting the altitude to 10,000 (as I said previously would the floor), then checking speed in case of structural damage, etc. No "emergency descent setting" - those are simply normal settings in the autopilot. In every single case, the pilot must be conscious, and if aware that a descent must be initiated, would most certainly already be on O2. No hypoxia.

[trisham]

http://www.skybrary.aero/index.php/Emergency_Descent:_Guidance_for_Controllers