PJ2 :
Before crew-change point, a formal briefing would be conducted by the crew, for the crew member returning from break. Position, altitudes, pending clearances, any weather, fuel state, aircraft performance, communications...(which ATC was next to be called), etc and the seat change would occur. The last crew member on break would normally be brought up a bit earlier to ensure wakefulness for the descent, approach and landing.
I personally raised that pointa long time ago but it got lost in the multiple waves of speculations then:
There is no SOP for determining the rest periods of the technical crew during the flight, but there is a very strong tradition established.
As PJ2 said, take out the climb and descent times, divide by three the remaining flight time, et voilą!
For AF447, they took off at 22:29 Z for a planned flight time of 10:34 hrs.
Simplified to the nearest ten, that's
- a T/O at 22:30 z
- a landing at 09:00 z
- The rest period of each pilot will be 10:30 - 1 = 9:30 : 3 = 3:10 hrs.
- They 'd then had crew changes at :
TOC + 3:10 = 23:00 z + 3:10 =
02:10 z : first crew change, and
02:10 z + 3:10 = 05:20 : second crew change.
The three pilots will be again together at 08:30 z TOD for a touch-down at 09:00 z.
Among the CRM / Human factors that the investigators are going to concentrate on, a few seem quite important :
- The accident happened very soon after the crew relief, at one of the worst times for vigilance...
- The AF procedures don't allow LHS qualifications for the F/Os.
That means that the captain must be at his LHS for T/O and LDG. Which makes him take in 99% of the flights the middle slot.The fact that his body was recovered, and not the other two seem to confirm that fact.
- In all certainty, the operation of this flight was performed by a senior F/O seating on the RHS with command functions and a junior F/O seating on the LHS with basic radio-com and navigation duties, along with some minor engineering duties.
IMVHO, we are very far from an optimum use of the flight deck crew's capability as the PF/PM duties are made difficult because of that task distribution : ECAM actions from the LHS are not that obvious and in many cases, there is a risk for the RHS pilot to lose his main flight instrument panels.
- Still IMVHO, the risk of locking the captain out of the flight deck, for security reasons is immense. Maybe there's a way around it.
- Finally, there is the question about severe weather or not ; in this partial scenario, of course the captain wouldn't have left his seat had there been a mearest risk of hitting one.
Just my two Euro cents