RNAV/VNAV with Commander 114
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@Darth-Patzer The autopilot is driven by the hot-swapping GPS avionics, so its capabilities are the same as any other aircraft with those avionics. If you're referring to approach vertical guidance from the GTN 750, then yes, it will fly the prescribed vertical profile.
@Black-Square There are planes with GTN750 with no vertical guidance in RNAV approach (ex: Beaver) that's why I ask. There are also planes with GTN750 and no RNAV (ex: A2A Comanche)
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@Black-Square There are planes with GTN750 with no vertical guidance in RNAV approach (ex: Beaver) that's why I ask. There are also planes with GTN750 and no RNAV (ex: A2A Comanche)
@Darth-Patzer What you're asking is if the autopilot can fly the vertical path - in which case, yes it can. the S-TEC should automatically arm approach mode and capture the vertical path. The Comanche and Beaver can also fly RNAV LNAV + V and LPV with the appropriate gps unit, you just have to hand fly the approach (or at least manually descend on the vertical path). For the record, I have never actually used autopilot for an instrument approach irl.
CPL MIFR 🍁
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On the topic of RNAV, specifically the RNAV-511. Is it correct what the manual says, that WP1 and WP2 both reference NAV1's frequency? I was using it tonight and it sure did seem like WP2 was referencing the VOR I had on NAV2. The distance and bearing info it was showing made no sense until I switched NAV2 to the same freq as NAV1. It would be more useful if WP1=NAV1 and WP2=NAV2, imho.
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On the topic of RNAV, specifically the RNAV-511. Is it correct what the manual says, that WP1 and WP2 both reference NAV1's frequency? I was using it tonight and it sure did seem like WP2 was referencing the VOR I had on NAV2. The distance and bearing info it was showing made no sense until I switched NAV2 to the same freq as NAV1. It would be more useful if WP1=NAV1 and WP2=NAV2, imho.
@rinkerbuck I've already fixed this for the next update. I found that while flying it was much more confusing to switch back and forth between the NAV radios. This way, you only have to press the swap button on the radio, and the waypoint button on the RNAV. Otherwise, you can't consistently monitor NAV 2 for crossing radials on the second localizer. This way, primary navigation information stays in place on the top, and secondary information on the bottom.
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@Darth-Patzer What you're asking is if the autopilot can fly the vertical path - in which case, yes it can. the S-TEC should automatically arm approach mode and capture the vertical path. The Comanche and Beaver can also fly RNAV LNAV + V and LPV with the appropriate gps unit, you just have to hand fly the approach (or at least manually descend on the vertical path). For the record, I have never actually used autopilot for an instrument approach irl.
@SadBucket For me VNAV works on the Beaver in MSFS2020 but not in MSFS2024. With the Comanche there is no NAV mode but ST, HD, TRK modes so how can it have RNAV capabilities ? I doon't think a DCT to a WP is possible for example.
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@Darth-Patzer Once again you are referring to the autopilot. To clarify, when I refer to an aircraft’s RNAV capabilities, I’m referring to the navigation system itself (GPS/FMS and associated avionics), not whether the aircraft has an autopilot.
An aircraft is RNAV capable if it has an approved RNAV navigation source (typically a certified IFR GPS) and the required approved installation of a compatible CDI/HSI for lateral guidance. An autopilot is not required, nor is vertical guidance. This is why LNAV minima exist on RNAV approach procedures. Pilots have been hand-flying RNAV routes and RNAV (GNSS) approaches since long before GPS-coupled autopilots became common. Just be sure to select the correct CDI source on your GPS unit.
The type of RNAV approach you can fly depends on the capabilities of the GPS and its certification. For example:
- A non-WAAS GPS may be limited to LNAV minima.
- A WAAS GPS can provide LPV guidance where published and approved.
- It is also important to distinguish that LNAV + V also exists as an option on many WAAS capable GPS units and that it is strictly for advisory guidance to LNAV minimums only. The GPS unit usually displays and confirms whether you are flying an LPV or LNAV (+V) approach.
- LNAV/VNAV is for aircraft utilizing an uncompensated baro VNAV system only which is not usually equipped on GA aircraft and is generally mainly used by airliners.
During an RNAV approach, the GPS provides lateral guidance through the CDI just like a VOR or localizer. If the unit supports vertical guidance (such as an LPV approach), it may also output glidepath guidance to the CDI/HSI. The pilot can simply hand-fly the lateral CDI and either manually fly the descent on the procedure for the LNAV only approach, or hand fly the vertical glidepath indications if available to the LPV minima. An autopilot, if installed, can follow those signals, but it is only an aid and it is not what makes the aircraft RNAV capable.
Feel free to lmk if u have any questions... sorry for the long answer
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@Darth-Patzer What you're asking is if the autopilot can fly the vertical path - in which case, yes it can. the S-TEC should automatically arm approach mode and capture the vertical path. The Comanche and Beaver can also fly RNAV LNAV + V and LPV with the appropriate gps unit, you just have to hand fly the approach (or at least manually descend on the vertical path). For the record, I have never actually used autopilot for an instrument approach irl.
@SadBucket said in RNAV/VNAV with Commander 114:
For the record, I have never actually used autopilot for an instrument approach irl.
Same. Most of the planes I flew didn’t have autopilot or GPS, those that did have AP it was so bad we would never use it. Proper trimming was much better.
In the sim I try to handfly as much as possible, even in aircraft like the King Air or Citation CJ4. Why let George have all the fun??
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@rinkerbuck I've already fixed this for the next update. I found that while flying it was much more confusing to switch back and forth between the NAV radios. This way, you only have to press the swap button on the radio, and the waypoint button on the RNAV. Otherwise, you can't consistently monitor NAV 2 for crossing radials on the second localizer. This way, primary navigation information stays in place on the top, and secondary information on the bottom.
@Black-Square said in RNAV/VNAV with Commander 114:
@rinkerbuck I've already fixed this for the next update. I found that while flying it was much more confusing to switch back and forth between the NAV radios. This way, you only have to press the swap button on the radio, and the waypoint button on the RNAV. Otherwise, you can't consistently monitor NAV 2 for crossing radials on the second localizer. This way, primary navigation information stays in place on the top, and secondary information on the bottom.
Well how does it work in the real aircraft avionics?
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@Darth-Patzer Once again you are referring to the autopilot. To clarify, when I refer to an aircraft’s RNAV capabilities, I’m referring to the navigation system itself (GPS/FMS and associated avionics), not whether the aircraft has an autopilot.
An aircraft is RNAV capable if it has an approved RNAV navigation source (typically a certified IFR GPS) and the required approved installation of a compatible CDI/HSI for lateral guidance. An autopilot is not required, nor is vertical guidance. This is why LNAV minima exist on RNAV approach procedures. Pilots have been hand-flying RNAV routes and RNAV (GNSS) approaches since long before GPS-coupled autopilots became common. Just be sure to select the correct CDI source on your GPS unit.
The type of RNAV approach you can fly depends on the capabilities of the GPS and its certification. For example:
- A non-WAAS GPS may be limited to LNAV minima.
- A WAAS GPS can provide LPV guidance where published and approved.
- It is also important to distinguish that LNAV + V also exists as an option on many WAAS capable GPS units and that it is strictly for advisory guidance to LNAV minimums only. The GPS unit usually displays and confirms whether you are flying an LPV or LNAV (+V) approach.
- LNAV/VNAV is for aircraft utilizing an uncompensated baro VNAV system only which is not usually equipped on GA aircraft and is generally mainly used by airliners.
During an RNAV approach, the GPS provides lateral guidance through the CDI just like a VOR or localizer. If the unit supports vertical guidance (such as an LPV approach), it may also output glidepath guidance to the CDI/HSI. The pilot can simply hand-fly the lateral CDI and either manually fly the descent on the procedure for the LNAV only approach, or hand fly the vertical glidepath indications if available to the LPV minima. An autopilot, if installed, can follow those signals, but it is only an aid and it is not what makes the aircraft RNAV capable.
Feel free to lmk if u have any questions... sorry for the long answer
@SadBucket Of course I refers to the autopilot, the GPS can provides all informations it wants to the autopilot if the autopilot don't know what to do with these informations the plane will not follow the flight plan by itself. Of course I can fly the plane by myself but it's not what I'd like to do (not all the time)
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@Black-Square said in RNAV/VNAV with Commander 114:
@rinkerbuck I've already fixed this for the next update. I found that while flying it was much more confusing to switch back and forth between the NAV radios. This way, you only have to press the swap button on the radio, and the waypoint button on the RNAV. Otherwise, you can't consistently monitor NAV 2 for crossing radials on the second localizer. This way, primary navigation information stays in place on the top, and secondary information on the bottom.
Well how does it work in the real aircraft avionics?
@rinkerbuck In this instance I believe the way you want it to be configured in your aircraft irl.
@Darth-Patzer Fair enough, I just wanted to clarify since it sounded like you were asking about RNAV capabilities as opposed to just autopilot capabilities. I also just love to explain things.
