I previously posted my concerns about compatibility between a box made by one manufacturer and a related box made by another. In the case at hand, the two are the Skview display/autopilot and the GTN 650 in my RV-14A. Specifically, they have worked just fine for 450 hours in flying both ILS and LPV approaches. The problem is with enroute VNAV, which came about with Garmin?s 6.51 and 6.62 software upgrades. I have never been able to get the Skyview system to ?see? enroute VNAV from the 650 or to fly it and wonder if anyone else has the same problem or a solution. I've previously sent this to Dynon but without a resolution. Again, this is not regarding approaches as they work well. It just involves enroute VNAV.
To frame this better for you, I'll indicate below what the 650 does regarding enroute VNAV versus what my Skyview system does with that same data:
650
1. Assume I get this ATC directive when eastbound: descend to cross 10 west of ABC at and maintain 7000 feet.
2. In the 650 I select the ABC fix, select 10 miles short of it and enter this new point in the flight plan.
3. I then select the altitude block for this point, put in 7000, set a desired descent rate and press save.
4. The 650 moving map now shows the new fix, the top of descent (TOD) point and the bottom of descent (BOD) point based on my chosen descent rate and the ground speed.
5. As the aircraft approaches TOD on the 650 moving map, a countdown timer indicates how many minutes and seconds there are before the descent should start.
6. Once TOD is reached, the timer resets to show how many minutes and seconds remain until BOD.
7. All of the above works every time in the 650 as it computes and displays this descent.
What Skyview (SV) does after the above 650 set up is complete
1. The letters ATK (for along track) appear on the SV screen 10 miles west of ABC.
2. No TOD or BOD points are shown on the SV screen.
3. With my SV autopilot on nav and altitude hold I set 7000 into the altitude pre-select window for the crossing altitude.
4. I press VNAV on the autopilot control panel and nothing changes. I do not get the down arrow showing the autopilot is armed to capture VNAV as it does when I am on an ILS or LPV and select VNAV for glideslope capture.
5. The aircraft remains at cruise altitude as the 650 countdown timer and 650 moving map both show it approaching the TOD point, which is indicated on the 650 screen but not on the SV screen. The aircraft then continues past the TOD point on the 650 but never leaves cruise altitude even though the 650 is now counting down minutes and seconds to the BOD point.
6. The aircraft continues on past the BOD point on the 650 display still at cruise altitude.
7. SV never does anything in response to this VNAV setup on the 650. It is as though no vertical nav data from the 650 is reaching the Skyview autopilot or if it does reach SV, the autopilot does not respond to it.
I can manually command a vertical descent rate using the SV autopilot and monitor the aircraft to keep it near the 650's computed descent profile but I cannot get the autopilot to do that and it should.
If there is something I need to do differently regarding button pushing sequence and the like I would like to know as nothing I have tried will work. I cannot believe I am the only SV owner with a 650 who has this problem.
To frame this better for you, I'll indicate below what the 650 does regarding enroute VNAV versus what my Skyview system does with that same data:
650
1. Assume I get this ATC directive when eastbound: descend to cross 10 west of ABC at and maintain 7000 feet.
2. In the 650 I select the ABC fix, select 10 miles short of it and enter this new point in the flight plan.
3. I then select the altitude block for this point, put in 7000, set a desired descent rate and press save.
4. The 650 moving map now shows the new fix, the top of descent (TOD) point and the bottom of descent (BOD) point based on my chosen descent rate and the ground speed.
5. As the aircraft approaches TOD on the 650 moving map, a countdown timer indicates how many minutes and seconds there are before the descent should start.
6. Once TOD is reached, the timer resets to show how many minutes and seconds remain until BOD.
7. All of the above works every time in the 650 as it computes and displays this descent.
What Skyview (SV) does after the above 650 set up is complete
1. The letters ATK (for along track) appear on the SV screen 10 miles west of ABC.
2. No TOD or BOD points are shown on the SV screen.
3. With my SV autopilot on nav and altitude hold I set 7000 into the altitude pre-select window for the crossing altitude.
4. I press VNAV on the autopilot control panel and nothing changes. I do not get the down arrow showing the autopilot is armed to capture VNAV as it does when I am on an ILS or LPV and select VNAV for glideslope capture.
5. The aircraft remains at cruise altitude as the 650 countdown timer and 650 moving map both show it approaching the TOD point, which is indicated on the 650 screen but not on the SV screen. The aircraft then continues past the TOD point on the 650 but never leaves cruise altitude even though the 650 is now counting down minutes and seconds to the BOD point.
6. The aircraft continues on past the BOD point on the 650 display still at cruise altitude.
7. SV never does anything in response to this VNAV setup on the 650. It is as though no vertical nav data from the 650 is reaching the Skyview autopilot or if it does reach SV, the autopilot does not respond to it.
I can manually command a vertical descent rate using the SV autopilot and monitor the aircraft to keep it near the 650's computed descent profile but I cannot get the autopilot to do that and it should.
If there is something I need to do differently regarding button pushing sequence and the like I would like to know as nothing I have tried will work. I cannot believe I am the only SV owner with a 650 who has this problem.
