I have mostly ignored the Flight Director in my time, as one of the things I like about the F28 are the 'old school' systems and how nice and easy it is to precisely hand-fly.

But I made an effort to integrate the FD functions into my procedures, especially since I recently acquired a Pilot's Guide to the Collins FD-Series Integrated Flight System in a stack of old aviation-related papers and brochures at a jumble sale - as used in the F28!

As far as I can tell the F28 features a version of the FD108 or FD109 system (also used in the B727, early B737, the BAC 1-11 and the DC-9).

The manual says the JF F28 doesn't model the Speed Control function on the FD. I assume there is a good reason for this, but I was wondering exactly why? The Pilot's Guide says that when selected this ties the Fast/Slow Speed Bug indicator (which is functional on the JF F28) to the Flight Director bars. So the basic functionality would seem to be there? Hitting the palm switches on the throttles would automatically set the Flight Director to SC mode, with the speed bug set to the Two Engine Best Climb Speed by the crew as part of the approach checks. The palm switches are on the JF model, but 'disconnected'.

The JF manual suggests (but doesn't outright state) that the Altitude Hold mode on the Flight Director is functional. But it doesn't seem to be - when selected it just indicates nose-level (same as if the pitch selector is set to Zero) and doesn't move regardless of the height of the aircraft. According to the guide "the V-bars in the flight director indicator will command climb or descent as necessary to maintain the barometric altitude indicated on the altimeter at the time the altitude hold switch was engaged."

Something amiss? Another 'fitted for but not with' item? Am I doing something wrong?