An auto-slew course pointer is NOT required.
Ok thank you @wigglyamp and Peter.
The idea would be to go first with a gtn650 linked to the KI525 and KFC150 and maybe later replace the KI525 by an EHSI (G5)….
Any wiring advice for such a plan?
Thomas
Peter wrote:
And it gets really seriously messy (and arguably dangerous) if you have GPSS / roll steering, where (in one common implementation) the GPS sends an ARINC429 steering data stream directly to the autopilot, so the plane just flies whatever the track is while the HSI just sits there, not moving. That is why I would have an EHSI (auto slewing course pointer) presentation for any serious IFR stuff.
I guess I must be living dangerously. 
I have had GPSS on my autopilot since Sept 2000 and still have my KI525. If I don’t set the course pointer to agree with the DTK, my GNS530W will bitch until I do. GPSS aka roll steering is the biggest autopilot improvement to come along. Not changing the HSI pointer has no affect on the course being flown, it is only good practice for visualization. After all the autopilot is handling things in the first place, even if the pilot forgets.
TomTom wrote:
I am being told that under EASA, an EHSI would mandatory to fly any RNP approaches???
EHSI is mandatory only for procedures with RF legs.
Airborne_Again wrote:
EHSI is mandatory only for procedures with RF legs.
Ok thank you, I am going to try to find it in AMC20-27 or 28.
Tom
From here
RobertL18C wrote:
The GNX 375 would mean a third GPS or replacing the 430 with a COM. I realise WAAS EGNOS gives you LPV, but for SEP light IFR LNAV is ok for me.
Robert something that was ( a small part) of my motivation to go to WAAS. E.g currently the new approaches at EBLG are based on RNAV to ILS. This means there is an RNAV transition to ILS. These transitions are not available in the KLN90 I am not sure about the GNS430? You still can fabricate the transition yourself and add the waypoint to fly it and than sequence to the IAP (available in the KLN) eventually intercepting the ILS as published. However the AIP mentions RNAV1 for the transition. This means the accuracy should increase flying these transition points. When you add them the accuracy does not increase unless for the KLN you select decrease the CDI deflection to 1Nm or even 0.3 …..I think it becomes more and more difficult to comply… The KLN90B is approach capable like the 430 non (SBAS) WAAS but how far?..In the GNX I would be able to load the Transition and the Approach in a couple of clicks and be fully within the spec.
Vref wrote:
However the AIP mentions RNAV1 for the transition. This means the accuracy should increase flying these transition points. When you add them the accuracy does not increase unless for the KLN you select decrease the CDI deflection to 1Nm or even 0.3 …..I think it becomes more and more difficult to comply… The KLN90B is approach capable like the 430 non (SBAS) WAAS but how far?.
The non-SBAS GNS430 is TSO’d for RNAV 1. As you say, it can do RNP APCH which is 0.3, so no doubt it can handle these transitions.
Airborne_Again wrote:
The non-SBAS GNS430 is TSO’d for RNAV 1. As you say, it can do RNP APCH which is 0.3, so no doubt it can handle these transitions.
Indeed:
This topic was handled already in the past with a good response from NCYankee above.
Most TSO C129 systems are excluded in the US because the database does not support a course to fix leg type. Many such systems are capable of using an OBS mode to perform a course to a fix, but this is not permitted because the entire procedure must be loaded from the database, and as previously indicated, this is not supported on most of the older GPS systems including the KLN90B, KLN89B, KLN94, GPS155/XL, GNC300/XL and others.
So to me its just not only the LNAV capability but the way how the procedure is loaded as one piece of consecutive path and terminators. Further to that the approach clearance give by ATC should refer to that also as published in the AIP as such you know exactly which transition to load from the database.
but this is not permitted because the entire procedure must be loaded from the database
Debatable… but another topic.
Vref wrote:
this is not permitted because the entire procedure must be loaded from the database
I’m not aware of such a regulation. Do you have a reference?
Of course, many procedures may not be possible to enter manually if you want the navigator to behave correctly. AMC3 to NCO.OP.116 does say that you shouldn’t modify a procedure loaded from the database, but that’s a different thing.
Airborne_Again wrote:
I’m not aware of such a regulation. Do you have a reference?
Good challenge :-)…..AC No: 90-101A this id for RNP AR although
https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_90-101A_CHG_1.pdf
(8) Capability to Load Procedures from the NDB. The navigation system must have
the capability to load the entire flight procedure into the RNAV system from the onboard NDB.
This includes the approach (including vertical angle), the missed approach, and the approach
transitions for the selected airport and runway
If you look here also its mentioned in the aircraft spec:
ICAO
Capability to load the entire approach, by name, from the
on‐board navigation database
