Adding to the excellent first post; in 1974 BLEU became Flight Systems 2 (FS2), part of Operational Systems Division, FS1 was the old Aero Flight. The two amalgamated into Flight Systems Squadron circ 1976/77.
The All Weather Operations research continued with the Economic Category 3 Programme (1975-1980) using the BAC1-11 and HS748.
The BAC1-11 retained ‘2 out of 3’ channels of the Smiths SEP5 ‘Trident’ autopilot and the autothrottle, but the FD was a single cue FD108. The research concentrated on human capabilities of manual landing in low visibility if a simpler (cheaper) flight guidance system failed. This work also considered the problems of low altitude manual go-arounds.
The HS748 retained the Smiths Series 6 autopilot/autothrottle and split cue FD which enabled auto and manual Cat 2. A new simplex monitored autoland module was developed for the Economic Cat 3 work, although many fog landings were completed manually from a DH of 50ft.
Both aircraft could be equipped with an airborne fog simulation – a pitch/roll stabilised ‘fog blind’ and translucent screens. Late in the programme a Monohud was evaluated, again available for both aircraft.
A lot of parallel research was flown in support of the lighting division, where approach and runway lighting, PAPI, and runway markings were developed. That team also worked on the structure of fog, and the measurement and reporting of RVR.
In the late 70’s money was drying up so other research programmes were sought. Both the BAC1-11 and HS748 were used for the UK MLS trials, with the HS748 demonstrating the system in Berne and Tehran; this work also continued previous research into steep and two stage approaches with associated noise measurement.
There was some parallel AWO work with helicopters, primarily for naval operations; this was extended into the Harrier trials for seaborne operations.
The BAC1-11 had a versatile autopilot facility – a programmable addition to the existing flight guidance system. This work looked at new control laws and methods of control – alpha autothrottle, direct lift control, and the basis of fly by wire systems with artificially reduced longitudinal static stability. An early design of FMS was fitted and RNAV studied; the flight deck was converted to EFIS in 1979/80.
The HS 748 conducted some low level electro–optic trials for a military operation using an existing ‘fog’ LLTV.
I sense that the ‘BLEU’ fog / autoland work petered out in the 80s.