RNAV Approaches [answered]

Heronjr
Posts: 110
Joined: Tue Jan 20, 2015 1:04 am
RNAV Approaches [answered]

Post by Heronjr » Sat Mar 07, 2020 10:49 pm

I still don't know whether the KA is certified for RNAV approaches - anyway, I thought this certificate would come from the equipment installed and not from the bird structure.

The FMS shows us in DEP/ARR page all ILS, RNV, V/D, etc types of approaches at the destination field. So, they are there for us to use them, no?

Finally, I learnt how to program and fly the ILS approaches using auto-tuning and the A/P does the job automatically very well. But I just can't figure out how to fly RNAV approaches. With other equipment, we program the RNAV and, when approaching the interception for final, we just press the APP button and the GS comes alive.

Does this KA equipment can perform a RNAV approach? If yes, how? Rephrasing my question, I'd like to know if this KA equipment accepts Vertical Guidance in a RNAV-WAAS approach.

TIA
Regards

paul
Posts: 14
Joined: Sat Dec 21, 2019 10:26 pm
Re: RNAV Approaches

Post by paul » Sun Mar 08, 2020 10:45 am

From my understanding this thing can take RNAV down to LPV minima. It's been a while but as far as I remember you need to hit the APP button and it should descend with the glidepath.

Heronjr
Posts: 110
Joined: Tue Jan 20, 2015 1:04 am
Re: RNAV Approaches

Post by Heronjr » Sun Mar 08, 2020 3:27 pm

paul wrote:
Sun Mar 08, 2020 10:45 am
From my understanding this thing can take RNAV down to LPV minima. It's been a while but as far as I remember you need to hit the APP button and it should descend with the glidepath.
Roger that. I remember sometime ago I tried this and the "FMS/APPR" appeared on the AP announces but I did not see the GS diamond. I will give it a try later at a US LPV capable field. Thanks.

Regards

ryanbatc
Posts: 41
Joined: Thu Jun 30, 2011 9:36 pm
Re: RNAV Approaches

Post by ryanbatc » Sun Mar 08, 2020 4:24 pm

Try pressing VNAV then APPR

Heronjr
Posts: 110
Joined: Tue Jan 20, 2015 1:04 am
Re: RNAV Approaches

Post by Heronjr » Mon Mar 09, 2020 4:27 am

ryanbatc wrote:
Sun Mar 08, 2020 4:24 pm
Try pressing VNAV then APPR
Well, it worked at KRDD, landing North on a LPV approach. The GS diamond didn’t appear, but the VNAV cross was there commanding the vertical guidance all the way. I will try now at other fields. Thanks a lot for answering.

Regards

ryanbatc
Posts: 41
Joined: Thu Jun 30, 2011 9:36 pm
Re: RNAV Approaches

Post by ryanbatc » Mon Mar 09, 2020 10:28 pm

I was so used to using the GTN that I just pressed APPR. I believe the real plane uses the combo with VNAV added for approaches with LPV and LP mins.

tcarter.67
Posts: 47
Joined: Sat Dec 21, 2019 10:32 pm
Re: RNAV Approaches

Post by tcarter.67 » Mon Mar 09, 2020 10:49 pm

Unfortunately how would we know the correct procedures, the aircraft may eventually be bug free, but without proper documentation- what’s the point?

N4GIX
Posts: 1023
Joined: Mon Sep 06, 2010 3:47 pm
Re: RNAV Approaches

Post by N4GIX » Mon Mar 09, 2020 11:00 pm

Although for the Cessna Citation, there is a ton of information that is common to all FMS3000 that might help. Five hundred and eighty eight pages of sleep inducing instructions! :lol:

http://www.hatcheraviation.com/uploads/ ... _Guide.pdf

tcarter.67
Posts: 47
Joined: Sat Dec 21, 2019 10:32 pm
Re: RNAV Approaches

Post by tcarter.67 » Tue Mar 10, 2020 4:27 am

So it’s ok for Milvis to claim that you can’t give out the information out because of copyright laws and then post a link to someone else doing what they say they can’t do....
Sorry but I’m now confused and a little perplexed...if I didn’t know better I’d say it was just an excuse not to give us the information that you obviously have but can’t be bothered,.....

markus.buensen
Posts: 17
Joined: Mon Feb 17, 2020 8:41 pm
Re: RNAV Approaches

Post by markus.buensen » Tue Mar 10, 2020 12:50 pm

Dear all,

well, yes, certification of the real thing depends on the equipment installed.

The way you use the FMS and AP depends on the approach. If you intend to fly an LPV approach, you will use the APPR mode of the flight director. If you intend to fly an LNAV/VNAV approach, you use NAV and VNAV with the altitude selector set to the baro minimum. Technically there is a difference between the two approaches aside from the (usually) lower limits of the LPV approach, that is that an LPV approach shows angular deviation (like an ILS), while LNAV/VNAV provides linear deviation (i.e. distance in miles from the centreline and distance in feet from the descent profile). Either way, the approach needs to be properly coded in the FMS database.

Hope that helps a bit.

Best regards,

Markus

KenG
Posts: 157
Joined: Sat May 09, 2015 2:33 am
Re: RNAV Approaches

Post by KenG » Tue Mar 10, 2020 1:44 pm

A better description of GP comes from the PTM.
The APPR button is also used when flying a non-localizer-based approach to a DA (Decision Altitude). When established on final for an appropriate RNAV (GPS) approach, the APPR button will activate the approach mode (APPR FMS1 or APPR FMS2). When VNAV is then pressed, it will arm the vertical glidepath (GP) mode. This allows the FMS to follow a glidepath down to a published decision altitude (DA) minimum. This approach descent is based on barometric altitudes and does not consider a ground based antenna. Like the ILS glideslope, however, the GPS GP will disregard any preselected altitudes.
I normally teach it differently than described above, in that anticipate that the pilot has already armed VNAV either to descend from altitude or follow a STAR so I teach VNAV then APPR prior to the capture fix (the point prior to the FAF.) Thus you are already VPATH (a little wonky in the MV350 so I recommend VVS) and then press APPR which will transition to APPR FMS and arm GP in white on the right side of the scoreboard.

SBAS (Sattelite Based Augmentation System) has not been added to the MV350 that I am aware of. However, here are the differences in flying the approaches.
Flying the LPV Approach
Once an LPV approach is loaded in the CDU the integrity of SBAS is monitored continuously. Within 31nm of the destination airport “LPV TERM” will annunciate in white on the PFD. During this phase of flight CDI deflection will be ± 1nm. Baro-VNAV will be used with a Vertical Deviation Indicator (VDI) deflection of ± 500 ft.

When the aircraft is past the Final Approach Course Fix (FACF), the SBAS integrity is appropriate for the approach, and the course leg to the FAF is within 45 degrees of the inbound course, “LPV APPR” will annunciate in green on the PFD. The FACF is the fix immediately prior to the FAF. The change from LPV TERM to LPV APPR occurs at the FACF because the aircraft will transition from baro-VNAV to LPV VNAV. Baro-VNAV will be affected by the surrounding temperature and the two glidepaths may not coincide. The glidepath indicator (“snowflake”) may appear to move suddenly when transitioning from baro-VNAV to LPV VNAV and more time is needed to be established on glidepath before crossing the Final Approach Fix (FAF). If
VNAV is already selected on the flight guidance panel the aircraft will smoothly increase or decrease the rate of descent as required to center the new LPV glidepath.

Once LPV APPR is annunciated, lateral and vertical guidance is angular and will get more and more sensitive to course deviations during the approach descent. (This is similar to ILS and glideslope guidance). Lateral CDI deflections start at ± 1nm and will decrease to approximately ± 350 ft at the runway end. Vertical VDI deflections start at ± 500 ft and will decrease to the appropriate scale needed for that approach. The amber message “CRS TO FAF>45 DEG” will appear on the CDU if a “Direct-to” the FAF creates a leg more than 45 degrees to the inbound. Sequencing to LPV APPR will be delayed until the “Direct-to” leg is fixed.

Descent on the LPV approach is accomplished using the APPR and VNAV modes on the flight guidance panel. FMS APPR and VGP will be annunciated on the PFD. Missed approach operations are the same as non-LPV approaches
I am not sure the documentation could have been written to the details needed for this product in any time period that would be close to acceptable to MV or its customers. We would need a nearly bug free version to take the images for the avionics section, so that means the largest portion of the document would be written at the very end. My best guess is it would have taken another couple of years to do correctly. I base that on having written courseware and PTMs and thus having a very good idea of the manpower requirements.

N4GIX
Posts: 1023
Joined: Mon Sep 06, 2010 3:47 pm
Re: RNAV Approaches

Post by N4GIX » Tue Mar 10, 2020 5:52 pm

tcarter.67 wrote:
Tue Mar 10, 2020 4:27 am
So it’s ok for Milvis to claim that you can’t give out the information out because of copyright laws and then post a link to someone else doing what they say they can’t do....
Sorry but I’m now confused and a little perplexed...if I didn’t know better I’d say it was just an excuse not to give us the information that you obviously have but can’t be bothered,.....
I only posted that link to be helpful. This version of the FMS3000 manual is freely available and was the first item returned by a Bing search. Copyright law prevents anyone to "quote" too much from a published manual, which means we would have to write somewhere around 600 pages including screen captures, just for the FMS 3000, never mind another multi-hundred pages for the PL21 and many, many more pages for the rest of the KA systems.

Heronjr
Posts: 110
Joined: Tue Jan 20, 2015 1:04 am
Re: RNAV Approaches

Post by Heronjr » Tue Mar 17, 2020 11:49 pm

Thanks a lot, gents, for all the answers and great discussion around this subject. With that, now I am happily flying RNAV approaches with the KA. I did some even in many Australia Outback RNAV equipped fields.

Regards and please take care during this covid-19 hard time we're all living.

curtoavida
Posts: 18
Joined: Sun Mar 01, 2020 8:46 am
Re: RNAV Approaches

Post by curtoavida » Fri Mar 20, 2020 8:38 am

Hello... i want to use this topic for ask about VNAV descent because when i select my Star and APP in FMS, my route map shows up my TOD in pink color but when my star have some altitude restriction the VNAV doesn’t obey altitudes restrictions i come to high every time and my TOD not correct to obey the altitudes for example yesterday i was flying PAFA >> PAVD and in the PAVD have app by VOR (JOH) have to pass in this VOR about 7.800FT but when i descent By VNAV i pass about 20.000FT in this VOR(i was flying FL-300) in the FMS altitude set correctly for pass in this VOR’s but VNAV doesn’t obey the altitudes restrictions i was descent with GS-300 and VS - 1.500Ft/min... so what i’m doing wrong??...

KenG
Posts: 157
Joined: Sat May 09, 2015 2:33 am
Re: RNAV Approaches

Post by KenG » Sat Mar 21, 2020 2:20 pm

curtoavida wrote:
Fri Mar 20, 2020 8:38 am
Hello... i want to use this topic for ask about VNAV descent because when i select my Star and APP in FMS, my route map shows up my TOD in pink color but when my star have some altitude restriction the VNAV doesn’t obey altitudes restrictions i come to high every time and my TOD not correct to obey the altitudes for example yesterday i was flying PAFA >> PAVD and in the PAVD have app by VOR (JOH) have to pass in this VOR about 7.800FT but when i descent By VNAV i pass about 20.000FT in this VOR(i was flying FL-300) in the FMS altitude set correctly for pass in this VOR’s but VNAV doesn’t obey the altitudes restrictions i was descent with GS-300 and VS - 1.500Ft/min... so what i’m doing wrong??...
This needs to be its own topic as it is different than an RNAV approach.


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