I still use mine in the Jetprop via the Aspen display almost every flight that involves either manual control in the upper flight levels where the sensitivity of the controls is very high, or the manual portion of an instrument approach.
I also use it to cue up the go around pitch when flying missed.
A much easier to interpret visual cue than relying on raw data. I would not be comfortable flying the Jetprop without it, however it would be overkill in my Tecnam where everything happens much more sedately. I think it comes into its own on higher performance aircraft.
E
The FD is guidance (innerloop commands) to the pilot as a result of the outerloop computations. With only FD engaged AP off the pilot is made part of closing the outer loop (e.g, Flight control movements) to feed the innerloop
This sums it up nicely:
Outer Loop:
Provides the autopilot with navigation (guidance) function. It adds the intelligence to the process (e.g. tracking a radial, holding a speed, climbing a VNAV path) The outer loop tells the inner loop what pitch, roll or yaw to hold for the maneuver, then the inner loop executes this. All the “intelligence” involved is mainly done in this loop.
Examples of outer loop autopilot operating modes:
Roll modes:
HDG (Select & Hold)
Nav Track (Track Hold)
VOR/LOC (Capture & Track)
Lateral Navigation (LNAV)
FMS Lateral Navigation
Pitch (flight path) modes:
Altitude (Select & Hold)
IAS/Mach (Hold)
Level change
Altitude Acquire (Capture)
Vertical speed
Glideslope (Capture & Track)
Vertical Navigation (VNAV)
FMS Vertical Navigation
Flare
FPAH (Flight Path Altitude Hold)
Combines Roll and Pitch modes:
Approach
Go-Around
Control Wheel Steering (CWS)
Indeed. Using the FD keeps the entire autopilot system – except the servos – in the loop, so if the AP has packed up, the FD won’t work either. Also, on the KFC225, if the power-up tests of the servos fail, the whole system is useless.
Quote why wouldn’t you use the flight director?
I’ve never understood FDs. If I want the AP to fly my plane, I’ll press the button. If I want to fly it myself, that’s what I’ll do. I just don’t see the interest in replacing a bunch of servos with myself.
FDs remind me of the silly light on the dashboard of my car that wants to tell me when to change gear. If I wanted the car to decide when to change gear, I’d have bought an automatic. (Well, I would have done anyway, except it wasn’t available for the car I wanted).
Blimey, talk about making life hard for yourself, why wouldn’t you use the flight director?
G5 wont work a GI275 might….I am not sure if the glass is more reliable. You need a test bench for that KI256 :-)
Maybe time to consider a G5… or similar.
The FD deflection is not related to the instrument orientation
The “photocell” senses the FD deflection and provides feedback.
The pitch/roll pickoff coils (bent LVDTs basically) come straight out and don’t feed any internal circuits.
They are not the same. LH is vacuum KI256 and RH is electric. Different connectors etc.
Good point Ultranomad. I will check. But both were installed previously, several times. The fix is just 2 resistors…
Until you figure it out Peter, why not swap L/R? The RH one appears to be fine.
As not using the FD to fly, that is a pity I think.
