Bearfoil wrote:-
mm43 I believe the a/c was in Aternate Law almost immediately, and #II at that. RTLU is auto at reversion, and will not release more sweep until Flaps/slats aiui. It also is not possible to reacquire Normal Law until landing and re program.
Yes, I fully understand the RTLU lock at Normal to Alternate Law and the slats extension to clear the RTLU locked position.
What I am seeking is clarification that RTLU WRN message will be generated at Law change. It seems like more information overload (e.g. Wind Shear Fault WRN at FL350!) and in that respect I suspect that a rudder pedal depressed and held created the reason for it.
A complete failure of all tail components is entertained at impact.
I agree with that.
If sufficiently left un snubbed by hydraulics, Rudder flutter could happen at almost any speed above the Stall. The definition of flutter would be strained at lower speeds, consider for now that the Rudder "vibrated" rapidly from max. aero pressure then back again.
That part I do not agree with. Let me put it this way.
- I don't believe the rudder was damaged at altitude.
- Damage occurred during the impact phase.
- The horizontal velocity component was relatively low.
- Departure of the V/S and Rudder was due to a complex combination of forces -
- Aerodynamic to terra oceania.
- Reactive buoyancy moments.
For instance the rudder's bottom damage is possibly a combination of the tail-cone/APU exhaust pipe being deflected into it and the rudder slamming hard-over to port as the hydraulics let go. There is absolutely (IMO) no signs of trailing edge "flutter" damage to be seen.
Initial bottom up compression through the aft frames compounded by the V/S downward thrust weakened the No.2/3 clevis mounts sufficiently for them to be torn out as the V/S rotated forward. Likewise, the No.1 mounts suffered a similar fate, but the lug mounts were ripped from the V/S as it rotated forward and to port. This indicates to me that longitudinal continuity still existed between the empennage and the fuselage forward of the aft pressure bulhead (frame 80) as this detachment took place.
No high speed impact damage with water is evident to the V/S composites as was noted on the Outer Spoiler.
NOTE: (IMO) I'm not so sure the horizontal impact velocity was even 100 knots. Recovered items, e.g. galley, toilets etc.. don't indicate that sort of speed. This was no "skipping stone" impact. The aircraft dug a watery hole and rapidly came to a complete stop, though then subject to the reciprocal buoyancy moments that completed the cycle of damage.
mm43