It must have been on a standard GPS/LNAV approach, for which the LNAV+V option (a virtual glideslope from the FAF to the MAP) has been provided in the Jepp database (i.e. has not been blocked by the existence of a “higher ranking” approach e.g. BARO/VNAV or whatever it is called) and the GPS was a WAAS box (430W/530W/GTN).
I am not saying this applies to you 
but I have flown with pilots who were very confused between the GNSx30 following a VOR or following a GPS. It is easily done unless you really know the kit. It is also installation dependent. It is made worse by most pilots not knowing how to use the OBS mode which is IMHO the best way to fly a VOR/NDB approach.
It must have been on a standard GPS/LNAV approach, for which the LNAV+V option (a virtual glideslope from the FAF to the MAP)
The more I think about, the more. I think that must have been it. One of the topics on that particular flight was familiarization of flying RNAV approaches, and I do not think I have ever flown a VOR approach at Rouen. But I definitely had the glide slope. I wonder why they would not provide VNAV guidance for VOR/NDB approaches?
how to use the OBS mode which is IMHO the best way to fly a VOR/NDB approach
I normally try to follow the VOR while keeping an eye on the FPL inset window on the PFD which will show the various intermediate points and distances. But some VORs are so flaky, like the one at LFPT (PON), that you end up flying wide turns alternately to right and left to keep the needle centered, so I often prefer to either use HDG mode (if using the A/P) with the VOR on the CDI, or use the GPS procedure overlay for the CDI. When using the OBS mode (I suppose you enter a DIRECT TO the station) you do not benefit from the fixes on FPL, including the MAP (or DA in the case of CDFA) but you will certainly have other means of determining that, and what does it do for the missed approach?
I would never fly a VOR or NDB approach now other than in GPS mode. No need for OBS mode if the procedure is in the database. If you want to monitor the land-based aid and it makes you feel better then go ahead.
I would never fly a VOR or NDB approach now other than in GPS mode. No need for OBS mode if the procedure is in the database. If you want to monitor the land-based aid and it makes you feel better then go ahead.
BUT …. if a particular VOR or NDB let-down procedure is missing from the current database of your NPA-certified GPS unit, you should conduct that procedure being guided by the appropriate ground-based navigational aid. “If it makes you feel better” and allows you to make the approach more “smoothly” and more “precisely” (i.e. in accordance with the procedure’s profile as published) do, by all means, utilise anything and everything else that is available to you and could assist.
[edited on poster’s request]
The more I think about, the more. I think that must have been it. One of the topics on that particular flight was familiarization of flying RNAV approaches, and I do not think I have ever flown a VOR approach at Rouen. But I definitely had the glide slope. I wonder why they would not provide VNAV guidance for VOR/NDB approaches?
WAAS advisory vertical guidance is only provided on eligible RNAV or GPS approaches and is specifically permitted in the TSO for the WAAS GPS as a manufacturer option. TSO C129/145/146 GPS may be used for situational awareness on approaches based on conventional ground Navigation facilities, but here in the US, part 91 operators may not use GPS to substitute for the lateral navigation for the final approach segment. So without lateral being able to be used, neither can the vertical. Certificated users operate under different rules and their Opspecs may permit substitution and also provide VNAV on NPA approaches.
So without lateral being able to be used, neither can the vertical.
Of course it can! In my experiment with the G1000, I could very well manually set up the waypoints for a conventional NPA approach, activate VNAV and then fly the lateral part of the approach using conventional navigation aids and the vertical part with VNAV guidance. Still observing any altitude restrictions of course!
For an NDB approach, I would (VNAV or no) definitely prefer to fly using GPS guidance and cross-check with the ADF (which I am 99% sure is legal in Europe), but if that should happen be illegal (here or in the US…) you can just follow the ADF needle as you would in any NDB approach and ignore the CDI (or better yet — select NAV for the CDI and dial in an unused VOR frequency — in that way you won’t be tempted to illegally follow any GPS guidance).
I am not saying you can’t do what you want and work around the system. I am saying that you will not find a certified TSO C145/C146 system that will support vertical guidance on a ground based approach as it will not be included in the approach database for that capability.
AC 90-108 provides guidance to pilots in the US regarding suitable use of RNAV equipment on a conventional procedure: I have highlighted some sections of the guidance that US operations are expected to abide by:
7. USES OF SUITABLE RNAV SYSTEMS.
a. Usage of Suitable RNAV Systems. Subject to the operating requirements in this AC, operators may use a suitable RNAV system in the following ways.
1) Determine aircraft position relative to or distance from a VOR (see first note in subparagraph 7b), TACAN, NDB, compass locator (see second note in subparagraph 7b), DME
fix; or a named fix defined by a VOR radial, TACAN course, NDB bearing, or compass locator bearing intersecting a VOR or Localizer (LOC) course.
(2) Navigate to or from a VOR, TACAN, NDB, or compass locator.
(3) Hold over a VOR, TACAN, NDB, compass locator, or DME fix.
(4) Fly an arc based upon DME.
b. Specific Allowances. The allowances described in this section apply even when a facility is identified as required on a procedure (for example, “Note ADF required”).
NOTE: For the purpose of this AC, “VOR” includes VOR, VOR/DME, and VORTAC facilities.
NOTE: For the purpose of this AC, compass locator includes locator outer marker and locator middle marker.
8. USES OF SUITABLE RNAV SYSTEMS NOT ALLOWED BY THIS AC. An otherwise suitable RNAV system cannot be used for the following:
a. NOTAMed Procedures. Unless otherwise specified, navigation on procedures that are identified as not authorized (“NA”) without exception by a NOTAM. For example, an operator may not use a RNAV system to navigate on a procedure affected by an expired or unsatisfactory flight inspection, or a procedure that is based upon a recently decommissioned NAVAID.
b. Substitution on a Final Approach Segment. Substitution for the NAVAID (for example, a VOR or NDB) providing lateral guidance for the final approach segment.
c. Lateral Navigation on LOC-Based Courses. Lateral navigation on LOC-based courses (including LOC back-course guidance) without reference to raw LOC data.
9. OPERATING REQUIREMENTS AND CONSIDERATIONS.
c. Operating Requirements.
(1) For the purposes described in this AC, pilots may not manually enter published procedure or route waypoints via latitude/longitude, place/bearing, or place/bearing/distance into the aircraft system.
