Next time I will try to film it 
You mean on older autopilots, I see.
The KFC225 can recapture LOC by disengaging APR, going back to HDG and doing APR again.
Usually you will be in ALT mode at this point, having descended to the IAP platform in ALT capture mode.
But IIRC it cannot recapture GS because it expects GS after LOC. I would have to test this though to be sure.
The other APs are irrelevant. The 225 is all in software
The KFC225 can recapture LOC by disengaging APR, going back to HDG and doing APR again.
Of course, you can always babysit AP with HDG or GPSS/NAV to intercept LOC when APR mode fails (I do it everytime on ILS)
I am sure your AP has ASI < X restriction, check your AFMS for “min AP speed”?
It does not have an airspeed input.
The KFC325 (used in the original TBM700) has airspeed input.
Obviously the KFC225 won’t work at speeds at/below Vs, won’t achieve +1000fpm at FL200, etc, but that’s diffusing the topic which was
because I was going too fast for the AP
@lbra is correct there is typically a minimum KIAS limitation which will be stated on the AFM Supplement for the type, however the AFMS on my KFC200 only states a max 175 KIAS speed limit.
The Bendix KIng AFMS is quite good on operation but is somewhat short on limitations (for example AGL minima, configuration, speed).
Based on height loss in different modes I limit operation to 700 feet AGL outside APPR CPLD, and while CAT 1 ILS approved, with a 70 foot potential height loss in APPR mode, I add 100 feet to DA if coupled. I also wouldn’t fly a coupled ILS with more than APPR flaps, and not below 90 KIAS. Finally, max rate of descent using the trim wheel is around 800 fpm, so CDFA of more than 4 1/2 degree slope at 100 knot GS would be impractical.
The KFC family seem to have a few quirks, for example as @Peter mentions they need to be established on the LOC before coupling to glide slope. Most radar controllers mixing puddle jumpers and jets will vector you straight onto the glide slope so the kFC family may struggle without a decent run in to FAF or GS.
It works because, vectored from the side, you pick up LOC before you pick up GS. I mean the AP looks for LOC and only then it looks for GS.
The AP doesn’t know what the platform altitude is
The problem may be intercepting the GS from above – I don’t think that works. @ncyankee may know. I haven’t had this for years; 2013 (Caen) was the last one. And I hand flew that one.
See also here.
The OP here was told he was going too fast, resulting in disconnection, but the KFC225 simply does not have that capability. It also won’t disconnect if too slow, because, ahem, it has no speed input. It will disconnect a bit later when you stall the plane and plummet
you can always babysit AP with HDG or GPSS/NAV to intercept LOC when APR mode fails (I do it everytime on ILS)
You have a defective AP.
Peter wrote:
The problem may be intercepting the GS from above – I don’t think that works. @ncyankee may know.
My understanding is that the KFC series can intercept from above or below. Once tracking the localizer, the intercept occurs after transitioning through the VDI center, from above to below or from below to above. Any vertical mode should work. Normally one is in Altitude hold and intercepts from below, but if you are above and set a pitch to command a descent rate greater than the GS rate, it will intercept from above.
This is a quote from the pilot guide for the KFC 200:
RobertL18C wrote:The Glideslope mode is armed for automatic capture if LOC front course capture has occurred. Automatic Glideslope capture occurs as the aircraft approaches the glide path from above or below.
Finally, max rate of descent using the trim wheel is around 800 fpm, so CDFA of more than 4 1/2 degree slope at 100 knot GS would be impractical.
Robert, is this what you have determined on your installation. The KFC manual says the trim can adjust pitch between +/- 15 degrees, although it is limited to 500 FPM when in alt hold mode to adjust altitude.
Ibra wrote:
Century AP in Archer not able to fly large crosswind drift on short final on VOR & LOC approaches as it has a limit on HDG/CRS: the issue is when you are too slow you hit max wind correction from crabbing (30deg), kicking a bit of rudder helps but don’t do it at 60kts
I have never needed to try it, but according to the manual it can fly larger drift angles if you help it by moving the HDG bug towards the wind.
I had a similar story with GFC500 on a DA42 while approaching Calvi on RNAV, more than 30kn crosswing, but very shaky while descending as wind is disturbed by the hills. AP just disconnects on a toght roll induced by turbulences, I finished by hand (and went around, it was an exercise – and it happened before my IRI asked me to disable it – may be he knew that AP will jump off).
But I’m not surprised, all AP have a tolerance about turbulences.
