Anybody know the answer to my question?
My system (430W/DFC90) will not fly a coupled approach inside the FAP/FAF. You have to use the Flight Director or do it manually.
boscomantico wrote:
Anybody know the answer to my question?
I don’t have access to a non-SBAS 430 as I write, but I have 430W and GTN simulators and in both of those if you activate the FAT, you get the correct sensitivity.
What do you understand by the expression “Activate the Approach” (I suspect that you may have misunderstood the concept?)
boscomantico wrote:
What is interesting by the way is that just as I was turning final and came up abeam EPOMA, the annunciation (of the GNS430) very briefly switched from TERM to APR and then switched back to TERM, which is where it then remained (expectedly).
We had the PPL/IR Europe PBN conference on Saturday, from which I learnt a great deal, as usual.
One of the other speakers told me that the TSO-C129 equipment does that, which is why the old AMCs required establishment on the FAT by 2 miles outside the FAF (which we had simply copied into the new AMCs, specifically AMC5 NCO.OP.116(c)). He also assured me that the TSO-C146 receivers do not behave in the same way, and are able to deal with tighter vectoring.
The original (old) post refers to an ILS, not LPV.
So it is purely down to the VHF (NAV) radio.
And the radio will display the correct deviations, regardless of how you got to the glideslope.
Bosco’s later post is about LPV and again surely the LPV receiver will show the right deviations regardless of how you got to where you are?
So isn’t this a case of the autopilot logic? Some autopilots need to see the LOC intercept first and only then they will arm the GS. Maybe even some will not intercept a GOS from above. I tried this a few weeks ago with my KFC225 (driven from a KX155A) at Dubrovnik and it did intercept the full ILS from a hand-flown start, so that’s not bad.
Peter wrote:
Doesn’t this also depend on the autopilot logic?
It does. Some autopilots do not have the logic at all…if they see a glideslope, they’ll have it…others do have to be underneath the slope, on the localiser, for a time period.
Mine, the Altimatic V FD, is even a bit odder. There are two controllers available, part numbers 4000317 – 8501 and 4000317 – 8502. The 01 requires the time under the slope and the 02 has a button on it to seize the glideslope from any direction. I would love to know the history behind the development of the two boxes; where they for different regulatory regimes, or do they reflect a change in regulation at a point in time, or what?
The DFC90 A/P which both bosco and i use will intercept the GS from above too.
But on both the ILS and RNAV approach with GS (LPV, LNAV/VNAV and LNAV+V) you have to be on the Localizer/Final Track at least two miles outside the FAP/FAF to fly a fully coupled approach.
The point of my post from yesterday was only about RNAV approaches. LNAV, precisely. Also, it was not about autopilots in any way. People tend to mix up navigator aspects with autopilot aspects all the time.
What I am trying to find out is whether the ATCO ’s enquiry if I could accept an 8 mile final on the RNAV approach 27 at EDFM was entirely nonsensical or not.
Therefore, I wanted to know if there are any navigators out there which, after turning final well inside the FAF, will still “regularly” complete the approach sequence (either automatically, or after some intervention of the pilot), meaning: switch to APR mode, reduce the CDI sensivity to 0.3 miles, etc . The GNS430 – expectedly – didn’t, i.e. it ultimately remained in TERM mode (despite sequencing to the RW27 waypoint) and even threw out a warning that the approach was not active. I am not aware that I, as a pilot, can manually force the GNS430 to go into APR mode after the conditions for doing so automatically (establishing on final at least a couple of miles outside the FAF) have NOT been met.
boscomantico wrote:
I wanted to know if there are any navigators out there which, after turning final well inside the FAF, will still “regularly” complete the approach sequence (either automatically, or after some intervention of the pilot)
And I answered that. It should sequence automatically, but if it doesn’t, you can activate the final approach leg. On the GNS the easiest way is to highlight the leg and click DCT DCT ENT. On the GTN touch the leg and press Activate leg. But it shouldn’t be necessary, it should just happen as you pass abeam the FAF.
