new rules to overlay approaches ?

[glass1/2full]

came across few different approaches that use to be overlay and now they no longer have the "GNSS" besides the approach identifier.
I am still able to pull it off the data base in the box.
example
cyam up until the last CAP,VOR RWY 30 use to be an overlay off the ssm vor. it either had the "GPS" or GNSS" I couldn't recall for sure but now it seems to me its a stand alone. It still comes up in the updated data base off the unit.
I look at cygq the VOR26 or 08 and they actually have the "GNSS". on the plate.
I cant seem to figure out, or come up with a logical answer as to why some approaches still have the GPS/GNSS overlay, and some use too, but don't anymore and yet still comes up on a current data base from the unit. ?

they cant be phasing out the overlay because some airports still have the GPS/GNSS overlay identifier next to the approach.

Is there something in the works cooking up at Nav Canada or are we just seeing the beginning of the end of all overlay approaches. ?

anyone that can shine the light would be greatly appreciated.

its 430 am and getting the lazy eye otherwise I would crack open the AIM and start digging.

[tferguson]

You may only legally fly an overlay approach for a traditional navaid if there is the suffix GNSS. You may even fly it using GPS if the navaid is U/S. Other VOR, NDB or ILS approaches will show up in Garmin databases without the GNSS designator. These may be used as reference only, and the underlying traditional navaid must be used & monitored, and reverted to should any discrepancies arise.

[ahramin]

Is there another GNSS approach to the same runway?

[photofly]

no, only an RNAV RWY12; nothing straight-in for 30 any more.

Looks like it just got withdrawn.

Which other airports?

[glass1/2full]

tferguson I understand the rules which applies to overlay very well, what can be and can not be done with a traditional navid that is an overlay with GNSS or GPS as mentioned in my post. my question was with regards to the change from an overlay up until recently to a non overlay on this publication of the CAP.
there has been quite a few airports effected by this, and cyam are only few that I mentioned. but I came across few in the north west and east of Ontario that this kind of change had occurred recently.
czke use to be an overlay ndb A and is now withdrawn to a non overlay. (up the west coast of james bay).
I will come up with the list of what I saw change in the last few months.


I was thinking maybe,they weren't flight checked recently by Nav Canada. that is just a guess though.

[DHC-1 Jockey]

I just asked someone in our 705 training department specifically about the VOR (GNSS) overlay to RWY 30 in CYAM. They said that we are still able to do the approach using the FMS (GPS) as long as 1) The approach appears in our FMS as a GNSS approach, 2) The associated navaid (in this case SSM VOR) is functional and 3) The associated navaid is monitored as a back-up to the GPS.

However, if the SSM VOR were to go off the air, we would no longer be able to do the GNSS approach. He was unsure of why GNSS was removed from the approach title, but we can still legally do it if the requirements are met.

[Big Pistons Forever]

Overlays were always intended to be an interim solution until proper LNAV "T" approaches could be developed. I wonder if it is just a case of things getting out of sync so that the overlay approaches were cancelled before a GPS approach was published.

The reformatting of the plates also probably comes into this. I can't see Navcanada changing an overlay to the new format just in time for it to be changed over.

[photofly]

I just asked someone in our 705 training department specifically about the VOR (GNSS) overlay to RWY 30 in CYAM. They said that we are still able to do the approach using the FMS (GPS) as long as 1) The approach appears in our FMS as a GNSS approach, 2) The associated navaid (in this case SSM VOR) is functional and 3) The associated navaid is monitored as a back-up to the GPS.

However, if the SSM VOR were to go off the air, we would no longer be able to do the GNSS approach. He was unsure of why GNSS was removed from the approach title, but we can still legally do it if the requirements are met.

Oh dear. Do special rules apply to 705 operations with respect to overlay approaches? A GNSS overlay approach doesn't rely on the VOR; you can fly it without the navaid.

if the SSM VOR were to go off the air, we would no longer be able to do the GNSS approach

If the underlying navaid is required, it's not a GNSS approach.

Hopefully this is a misunderstanding by me or by you, and not a case where your training department needs more training ...

[av8ts]

I think what Dhc-1 Jockey is trying to say is if the approach plate says its a (GNSS)VOR approach then no VOR is required however if the plate just says its a VOR approach then you can still use the fms/gps to fly the approach but the VOR must be serviceable and monitored.

[Airmanship Police]

Sounds to me like their 705 training department think it's okay to do an overlay approach if the app. is labeled GNSS in their FMS even if the plate does NOT say (GNSS) anymore.......

[av8ts]

Thats correct as long as the approach is in the fms data base.

[photofly]

Mr. Photofly

Thank you for your email.

The GNSS Overlay for RWY 30 CYAM was removed by NOTAM in October of 2013 as a flight inspection determined the procedure no longer met criteria for safety.

A full suite of RNAV procedures (including both LNAV/VNAV and LPV) have been developed for CYAM and are slotted for publication this year.

I hope this is helpful.

Regards,

John Michael (J.M.) Fleming
NAV CANADA
Customer Service - Service à la clientèle
1-800-876-4693
Toll-free Fax / Télécopieur sans frais: 1-877-663-6656
Direct Fax / Télécopieur direct: 613-563-3426

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-----Original Message-----

Sent: February-27-14 6:05 PM
To: Customer Service Centre/ Service à la clientèle
Subject: Question about the GNSS overlay for LOC RWY 30 at CYAM

Hello,

Could I know the technical reason why the GNSS overlay for LOC RWY 30 at CYAM was withdrawn in the 6 February update cycle?

Thank you

[Docbrad]

I heard that YAM is getting RNAV approaches all over, so they phased out the GNSS. They was an issue with one of them, so they didn't get implemented in this cycle. Keep an eye out for the RNAV in the near future.


Looks like photo fly beat me to it...

[Airmanship Police]

So if it was removed because it didn't meet the criteria, Is it still okay to do it if it's in your FMS database and your 705 training department says it is okay?

[ahramin]

I cannot comment for certain as I don't know what equipment DHC-1 flies, but many if not most multi sensor fms with gnss aircraft nowadays simply aren't designed to fly NPAs with traditional guidance. Every NPA is flown in map mode following fms guidance with no CDI. These aircraft are certified this way and traditional "can I use GPS guidance or not" overlay rules do not apply. Keep that in mind before deciding that their training department doesn't know what they are doing.

[turbo-prop]

I believe what his training department is saying is yes go ahead and fly the approach with the GPS, that depending on what type, will scale down to 1 mile and have the traditional navaid up in the back from reference. As long as the GPS/FMS is up to date and has the full approach in it then fly the approach in GPS/FMS mode but have traditional navaid up too. There is nothing wrong with this in my opinion, the gps would be used in nav mode and would fly the approach just fine. Like wise once inbound if you selected nav mode on the VOR approach it would fly just fine. But it is a lot easier now a days to fly an NDB approach with a GPS, but still have NDB in the back, where you can once again select GPS/FMS nav mode and follow the track inbound better then using your heading bug to chase the needle. Yes some people will call it lazy or whatever, I call it using all your resources to there potential. And yes I have been around long enough to have done it both ways and letting the GPS/FMS fly it, brings the workload down in the cockpit.

[Airmanship Police]

What if the approach plate does not say GNSS. Is it still cool to do it anyways?

[kev994]

What if the approach plate does not say GNSS. Is it still cool to do it anyways?

The GNSS bit only means you can fly the approach without referencing the traditional nav aid it is based on. If it doesn't say GNSS you need to monitor the navaid, nobody cares if you navigate with your heading bug or the fms so long as you stay within the parameters of the approach.

[Big Pistons Forever]

I guess what we need is a auto degrade mode for the GPS. It would put in random track errors and make sure that the aircraft is well off the runway centerline at the MDA so that it would look like you are using the ADF.

That straight line on ATC radar direct from the IF to the touchdown zone is a dead give away that you are illegally using the GPS even though the approach plate doesn't have the magic GNSS note.

[goldeneagle]

As mentioned in the email quoted above, approach was removed by NOTAM due to no longer meeting safety requirements.

so the question for training department, if it's still in the magic computer boxes, can you fly it still? Even with NOTAMS saying it's been withdrawn ?

[photofly]

The approach wasn't removed; the overlay was removed. You can still fly the LOC RWY 30 at CYAM.

[Maynard]

The approach wasn't removed; the overlay was removed. You can still fly the LOC RWY 30 at CYAM.

Actually, there hasn't been a LOC approach there for years....so no, you can't. I think you meant to say VOR 30...
http://www.fltplan.com/AwDisplayAppChart.exe?a=1

[RatherBeFlying]

BPF nailed it.

I guess what we need is a auto degrade mode for the GPS. It would put in random track errors and make sure that the aircraft is well off the runway centerline at the MDA so that it would look like you are using the ADF.

That straight line on ATC radar direct from the IF to the touchdown zone is a dead give away that you are illegally using the GPS even though the approach plate doesn't have the magic GNSS note.

For NDB approach simulation parameters, it should go off track with the crosswind 1 mile, then correct to 1/2 mile off on the upwind side of track one mile short of the threshold.

[av8ts]

According to our TC approved AOM it is perfectly legal to fly an NDB or VOR approach using the FMS/GPS as long as the NDB OR VOR are seviceable and monitored.

From the AOM "GNSS, NDB and VOR approaches should be flown utilizing the FMS if available. For NDB or VOR approaches that are not part of the GPS overlay program, pilots shall monitor ADF or VOR for final approach track guidance"

[Maxpwr]

Yes, to be clear you can use the FMS and fly a non precision approach if labelled GNSS without the nav aid even being on the air.

If the approach was NOT labelled GNSS then you may still do the exact same thing and fly the approach using the FMS but the traditional nav aid must be on the air and monitored by the flight crew. Monitored can simply consist of having that extra RMI needle pointing to it. Secondly if that RMI needle were to disagree with the FMS track then you must revert to (believe) the traditional nav aid.

Trust me DHC-1 Jockeys training department knows EXACTLY what they're talking about. Some of the smartest people I've known.