172 Re “… can you get CAT IIIA approved without autoland function?”
The inference of the regulations is that a manufacturer/operator can apply for Cat 3 approval involving an auto approach and a manual landing, and apparently without the need for HUD.
The difficulty (cost) is in providing the required proof that the landings can be made without excessive workload in the visibility conditions – a lot of simulation.
Also as an alternative, it appears that a FD approach could be used, but again providing proof that ‘every’ pilot will be able achieve the required approach accuracy with the FD is another cost issue. Most manufacturers are reluctant to certificate FD Cat 2 when the aircraft already has an autopilot; there are similar cost/certification issues with HUD; it’s not as cheap as 7sr suggests. Also, a HUD has flare guidance so is this a pure manual landing? ;-)
Although CS-AWO does not deal with visibility minima per se, it is normally in EU-OPS, the AFM could have an overall a system operating limit due to the manual landing case. Thus the RVR for a manual landing would almost certainly be higher than other Cat 3 operations. The operation is still Cat 3 due to the reduced DH – the complexities/differences in ICAO definitions and practical operations.
Re the 80% auto min ht use; this may have been suspended in EU-OPS, but it is a necessary safety margin to enable a manual take over after failure at low altitude.
However, if an operation specifies autopilot disconnect at DH – say 80ft, then the 80% rule below that may be waived as the pilot would be in the loop with or without failure at 80 ft; however a good safety case is required for failures between 80 and 100ft.
I suspect that the particular subsection of CS-AWO is aimed at an operation with a DH just below 100ft.
7sr “... autolandings can be nice...but if something went wrong...u have to be ready.”
What about with HUD …. if the PF ‘goes wrong’, no HUD failure – just poor pilot performance, then who “has to be ready” and what can be done?
The autopilot – autoland failure case normally requires a GA excepting if the required visual cues are clearly seen – enabling a manual landing, but with a HUD how do you determine if the pilot part of the system has failed - impending hard landing?