Roll surface damage?
CONF iture:
Here it was the rudder but what about one or more ailerons on AF447
?
RR_NDB:
It is technically feasible (and not costly) to detect this type of failure
(on the fly 
).
Looking at the aileron & spoiler traces:
If NOT in A/P control the outboard ailerons are centered (active zeroed) at speeds above 190Kts. (Active zero =1.4[/FONT]° up)[/COLOR]
(In A/P control or certain failure modes outboard. ailerons can be controlled up to 300Kts)
This transition is visible @ 02:10:05 at A/P drop off.
The trace shows also the outboard ailerons remain centered all the way down even when the CAS was well below 190Kts.
This could be another protection from the PRIMS (due to rejection of ADIRU's?)
The position is sensed by the LVDT inside the servo actuator and not the actual surface position.
There is no separate surface position RVDT like in the elevator and rudderdesign.
However the adjacent servo-actuator (while in dampening mode) is still monitored and since this one is driven by the aileron it reflects the actual surface position.
If there is any difference between the active and the dampening servo a fault message will be triggered. (And aileron faults were NOT present)
There were NO outboard aileron commands from PRIM and because there were also NO aileron fault messages present, we can conclude the surface was still attached.
However we CANNOT conclude nor exclude the outboard aileron surfaces were completely undamaged.
The inboard ailerons did receive commands, A/C did respond to these commands and failures were absent.
***
From the spoiler trace:
In ALT 2 spoiler (roll function) 2, 3 and 6 are inhibited.
The only glitch you will find in the FDR trace is after ~02:13:35.
Traces of spoiler 5 (cyan) & 6 (amber) shows peaks thereafter, this could be the moment the PRIM 1 and SEC 1 were switched off.
#5 is controlled by PRIM 1 and #6 is controlled by SEC 1.
If the peaks are caused by aerodynamic loads we can conclude the surface(partly?) was still connected to the servo. (Spoiler position is also derived from the servo-actuator LVDT).
Last edited by A33Zab; 12th Mar 2012 at 19:55.