@ Owain Glyndwr, mm43,HazelNuts39, AlphaZuluRomeo and all
I read the following out of the A330 technical training manual that AF447 had no high speed or low speed stability protection left (as it would have been iN Alt1), but only protection still available being the load factor protection.
ALTERNATE LAW WITH REDUCED PROTECTIONS
In pitch normal laws, all the protections are available.
In case of loss of surface actuation or of inputs, some protections can be lost. The pitch alternate laws with reduced protections are activated in the FCPCs in case of loss of :
- THS actuation (B+Y hydraulic circuit or 3 motors lost, ...) or - 2 Inertial
Reference (IR) (second self detected) or 2 Air Data Reference (ADR) o
- All spoilers or all inboard ailerons or
- Slat position or pedal position or
- One elevator (B+G or Y+G hydraulic circuit lost, ...).
The angle of attack (AOA) protection is lost and replaced by static stability Vc prot. (see Pitch Laws module).
The pitch attitude protection is lost.
The high speed protection (VMO1) is lost and replaced by high speed stability
VMO2. (see Pitch Laws module).
In case of loss of slat or flap position or aircraft weight computation, the static stability is also lost.
If a double IR failure occurs, the second being self detected, specific accelerometers are used to consolidate the load factor information and pitch attitude rate information from last IR.
franzl
ALTERNATE LAW WITHOUT PROTECTION
In this case, the pitch protections are lost except the load factor protection.
This alternate law without protection is activated in the FCPCs after a triple
ADR failure.