PPRuNe Forums - View Single Post - Malaysian Airlines MH370 contact lost
View Single Post
Old 11th Mar 2014, 23:04
  #1938 (permalink)  
MrWooby
 
Join Date: Apr 2002
Location: Sydney
Posts: 152
Likes: 0
Received 0 Likes on 0 Posts
Sounds to me like depressurisation, but you need to link depressurisation and transponder loss. This could be caused by structural failure taking out antennas, or electric supply loss on a common supply. Not sure about the 777 elec system but should have enough redundancy to ensure backups.

Following depressurisation, aircraft turned to return toward Malaysia and emergency descent. This is usually done on autopilot, so heading select and select alt of 10,000 or 14,000. Pilots would have donned oxy masks. However I wonder if there was a problem with the flight deck oxy supply. The company I worked for had a recent incident where the oxy supply to the flight deck was turned off. Not sure of the exact sequence but something like this. In doing the preflight oxy checks there was enough pressure in the oxy lines to enable oxy flow for the quick flick of the oxy test to ensure flow, at some stage during the flight the oxy pressure was found to be below minimum, it was then discovered that there was no oxy flow.

During emergency descent there would have been no flow if 100% oxy was selected, but if diluter demand air was selected they would have been breathing cabin air and would have passed out/died on descent. Aircraft would have descended to selected altitude. Level off and continued flying.
Looks like the track flown would have possibly taken them over Aceh, where terrain goes up to about 9000 feet in some areas, and then continued on in the Indian Ocean towards Diego Garcia until fuel exhaustion. Given endurance of say 7.5 Hours initially, aircraft would been flying about 5 hours at around 10,000 feet with speed brake out. Maybe at cruise speed around 300 kts.

Still many questions though. Pax oxy would have deployed, so pax should have been ok, but if only 15 mins oxy it would depend on the descent rate used in the descent. If pax alive over land then mobile phones would have probably been used. Cabin crew would have eventually entered the flight deck. If they found the crew deceased, maybe they tried to fly the aircraft and lost control.

Very Perplexing.
MrWooby is offline