Originally Posted by
usmcflyr
Originally Posted by
planespotta
if you have an fms or a gps, the vor will still be in the database even if it's been destroyed, as in the previous example, so i assume it would be fine to use. Or ask for alternate missed approach instructions before beginning the approach. don't rule the whole approach out just b/c the vor is ots, it might still be perfectly safe to fly.
this is what i like about the forum. The discussion that a seemingly simple question can produce, and the way that it gets people to get back into the books, enhances understanding and safety for all.
I didn't quite understand the sentence bolded above, but actually based on different circumstance and more of a technicality. I asked the question around the office and some agreed with the statement above. A little more research though from the group revealed two sources though that would contradict the notion that you could legally fly the (using the given example of kjvy and abb) vor rwy 18 approach using the 'overlay' philosophy.
First from the faa's gnss q&as:
(#21) gnss frequently asked questions - waas
q. I have heard about flying an “overlay” approach, and that it is basically flying a vor or other approach, but using the gps instead of the vor or adf. Can i just use the gps instead of the vor?
A. no. Overlay approaches can use gps instead of the primary designated navigational aid, but the approach must be designated for gps and be in the current aircraft database. For example, it must say “vor or gps rwy 16.” you cannot just use gps in lieu of vor, automatic direction finder (adf) or other navigational source naming the approach. You can, however, use gps to determine waypoints during the approach.
and then again in the aim (para: 1-1-19, pg 1-1-32)
g. Gps approach procedures
as the production of stand−alone gps approaches has progressed, many of the original overlay
approaches have been replaced with stand−alone procedures specifically designed for use by gps
systems. The title of the remaining gps overlay procedures has been revised on the approach chart to “or gps” (e.g., vor or gps rwy 24). therefore, all the approaches that can be used by gps now contain “gps” in the title (e.g., “vor or gps rwy 24,”“gps rwy 24,” or “rnav (gps) rwy 24”). During these gps approaches, underlying ground based navaids are not required to be operational and associated aircraft avionics need not be installed, operational, turned on or monitored (monitoring of the underlying approach is suggested when equipment is available and functional). Existing overlay approaches may be requested using the gps title, such as “gps rwy 24” for the vor or gps rwy 24.
Note
any required alternate airport must have an approved instrument approach procedure other than gps that is anticipated to be operational and available at the estimated time of arrival, and which the aircraft is equipped to fly.
therefore, technically the vor rwy 18 into kjvy could not be legally flown even if the facility was in the database unless the approach plate included the gps in the title (e.g. Vor or gps rwy 18). As that co-worker pointed out though, why would they do that when there is already a stand-alone gps approach to rwy 18 (the standard t configured straight-in).
Thanks again for bringing up such a discussion item.
What say the group?
Usmcflyr
Interesting, but it doesn't really address the Original Poster's situation and query. Your apparently contradicting citations deal with scenarios where the failed NAVAID is used for the final approach segment of the Instrument Approach Procedure. The TITLE of the IAP will only include the NAVAIDs or components required to execute the final approach portion, not those that may be required to get to the IAF, and not those that may be required to execute the missed approach. The examples you've given deal with a failed VOR that is required to execute the final approach segment, and which is named in the title of the procedure.
The OP's example is an ILS approach, so only the ILS is required in order to execute the final approach segment. The failed VOR in question is NOT required to execute the final approach segment, so the references you quoted would not apply. The failed VOR is only required in order to execute the Missed Approach procedure.
Originally Posted by
planespotta
completely agree with everything you said. Can't (legally...hehe) fly a vor-8 approach with gps overlay b/c "gps" isn't listed in the title, & why make 2 approaches when 1 would suffice?
The information wasn't wrong, it just wasn't pertinent.
Originally Posted by
planespotta
Additionally, however, in the op's example, the vor was what you'd be holding at after you went missed - not the primary navaid for the approach. In this case, if it's ots, why not request alternate missed approach instructions like a heading?
Right. Exactly. Clearance for alternate missed approach instructions would eliminate the need to have a functional VOR.
Originally Posted by
rickair7777
i agree 100% with usmcflyr (especially since he's quoting the book).
Unless other means are specified on the iap, in an notam, or verbally by atc, you need all required navaids. Atc might be able to give you an alternate missed, but they probably can't just waive a required navaid otherwise.
Again, nothing wrong with book quotes if they apply to the question asked. Those don't.
Originally Posted by
rickair7777
You can only use gps where published.
This applies to not only the obvious primary navaids but also to missed navaids and things like cross-radials which do not have a published alternate means. Would not apply to a step-down cross-radial on the non-precision if you are doing the ils, only what's required for the procedure you execute.
It applies ONLY to those NAVAIDs required for the Final Approach Segment, those named in the title of the Instrument Approach Procedure.
Originally Posted by
deadstick35
ref vor rw08 scenario: If you're enroute when you go nordo, you might not be with your final sector or might not have received the approach clearance. So, the likelihood of an alternate ma being received is slim. Unless there is a published fdc notam with an alternate ma procedure, for planning purposes, you'd need another iap.
Well, now you're adding a different dimension to the question, so the answer has to account for the new dimension. The OP asked if it was legal to FLY the approach. Now you're discussing flight planning considerations. You cannot, obviously, coordinate alternate Missed Approach procedures before you ever talk to the Approach Controller, so other provisions must be made. Perhaps it's a NOTAM describing alternate procedures, or perhaps it's the ability to use another navigation system (GPS) to define the point.
Originally Posted by
deadstick35
The op wrote about an ils with an inop vor for the missed approach hold waypoint. In that case, if so equipped, an ifr gps could be used for the ma segment.
I believe you are correct.
Back to the OP's original question. Only the ILS is required to fly the Final Approach portion of an approach titled ILS RWY XX. You may navigate to the Final Approach segment by any number of means, or you may receive radar vectors to the Final Approach segment. You must have SOME means to execute the Missed Approach segment. That may mean substituting a different procedure by NOTAM or by clearance from ATC, or it may involve using a GPS navigation system to determine the position and configuration of the published NAVAID.
In short, the answer is, "Yes, IF ..."
.