Use of Bearing Pointers- G1000

TDoc

Well-Known Member
On a VOR approach, is it legal to have the GPS LNAV/VNAV up to give you guidance with a VOR/ADF bearing pointer up for that approach and fly it that way assuming you put the altitude preselect to MDA. My understanding is yes, as long as that bearing point is in agreement with the GPS needles. My student just bought a G1000 equipped airplane, and I think this is a very valid way to do these approaches even easier/safer. This is how we teach VOR/NDB approaches in the GV/550. Any thoughts on why this wouldn't be an "faa approved" way to do this?
 

Champcar

Well-Known Member
On a VOR approach, is it legal to have the GPS LNAV/VNAV up to give you guidance with a VOR/ADF bearing pointer up for that approach and fly it that way assuming you put the altitude preselect to MDA. My understanding is yes, as long as that bearing point is in agreement with the GPS needles. My student just bought a G1000 equipped airplane, and I think this is a very valid way to do these approaches even easier/safer. This is how we teach VOR/NDB approaches in the GV/550. Any thoughts on why this wouldn't be an "faa approved" way to do this?
If its a VOR approach then you must use the VOR off the NAV Radio. You could select a bearing pointer of the NAV if you wanted to but why nut just use the CDI.

You can't just punch in the VOR in the GPS and dial in the radial and call it good. It doesn't work that way.
 

bdhill1979

Gone West
On a VOR approach, is it legal to have the GPS LNAV/VNAV up to give you guidance with a VOR/ADF bearing pointer up for that approach and fly it that way assuming you put the altitude preselect to MDA. My understanding is yes, as long as that bearing point is in agreement with the GPS needles. My student just bought a G1000 equipped airplane, and I think this is a very valid way to do these approaches even easier/safer. This is how we teach VOR/NDB approaches in the GV/550. Any thoughts on why this wouldn't be an "faa approved" way to do this?
The bearing pointers are not VOR information but GPS LOP representations and if you recall every time you load any approach other than a GPS approach the disclaimer about an aid to situational awareness pops up.

Yes they are great, yes they are very accurate, and yes they make your life much easier. But they do not replace the VOR that is supposed to be used on the approach.

Also I have heard of an FAA inspector busting guys using VNAV GPS fucntions on approaches that were not VNAV approved. Just using the function does not constitute a true LPV or VNAV profile.

Now if the G1000 is WAAS capable then using LPV or VNAV on a GPS approach is not an issue as the system is capable of those approaches, if the approach is approved for that.
 

Champcar

Well-Known Member
The bearing pointers are not VOR information but GPS LOP representations and if you recall every time you load any approach other than a GPS approach the disclaimer about an aid to situational awareness pops up.

Yes they are great, yes they are very accurate, and yes they make your life much easier. But they do not replace the VOR that is supposed to be used on the approach.

Also I have heard of an FAA inspector busting guys using VNAV GPS fucntions on approaches that were not VNAV approved. Just using the function does not constitute a true LPV or VNAV profile.

Now if the G1000 is WAAS capable then using LPV or VNAV on a GPS approach is not an issue as the system is capable of those approaches, if the approach is approved for that.
Thanks, after reading that I realize how rusty I really am.
 

TDoc

Well-Known Member
Ok, understood that if these "bearing pointers" were GPS derived and not actual vor source that would make it wrong. However, I'm looking at this Garmin manual from the DA-40 SVT, and it states that, "When NAV1 or NAV2 is the selected bearing source, the frequency is replaced by the station
identifier when the station is within range" and then "The bearing pointer is removed from the HSI and NO DATA is displayed in the information window if
the NAV radio is not receiving a VOR station"

I'd have to take this as actual VOR source information and not a GPS signal, as a gps would theoretically never be out of range. You can still do NDB approaches which is saying the same as a bearing pointer. So why not have the accuracy of a GPS and Vnav (assuming you check the crossing restrictions and a waas gps) and the bearing pointer up as your true source?
 

meritflyer

Well-Known Member
It's perfectly legal to use the GPS for an approach with the bearing pointer selected to the appropriate nav station.
 

awacs94

Well-Known Member
The G1000 bearing pointers have two selections. Lets say BRG 1. You can choose either Nav 1 or GPS, same with BRG 2. If you select Nav then you are receiving raw data from the navaid and not the GPS.
 

TDoc

Well-Known Member
The whole purpose of this is to never really have the dive and drive anymore by using the vertical guidance of the waas.
 

RynoB

That One Guy
It is acceptable to have GPS set as your CDI source, and NAV (VOR) set for your bearing pointer to fly VOR approaches. You should refer to your POH/AFM and avionics supplements to make sure that the manufacturer does not prohibit using the avionics this way.
 

bdhill1979

Gone West
Ok, understood that if these "bearing pointers" were GPS derived and not actual vor source that would make it wrong. However, I'm looking at this Garmin manual from the DA-40 SVT, and it states that, "When NAV1 or NAV2 is the selected bearing source, the frequency is replaced by the station
identifier when the station is within range" and then "The bearing pointer is removed from the HSI and NO DATA is displayed in the information window if
the NAV radio is not receiving a VOR station"

I'd have to take this as actual VOR source information and not a GPS signal, as a gps would theoretically never be out of range. You can still do NDB approaches which is saying the same as a bearing pointer. So why not have the accuracy of a GPS and Vnav (assuming you check the crossing restrictions and a waas gps) and the bearing pointer up as your true source?
Ok re reading the G1000 manual I must have misread this part. The distance information is GPS derived, but the direction is VOR data; Unless you have the Optional DME installed.

The whole purpose of this is to never really have the dive and drive anymore by using the vertical guidance of the waas.
Keep in mind that WAAS in and of itself does not provide vertical guidance, it merely allows it by its accuracy and ability to give an altitude as part of the GPS solution.

The Vertical guidance of say an LPV approach is part of the approach profile in the GPS database, not some path beamed down from the satellites.

Were you to use the VNAV function to arrive at the VDP of a non-precision approach there really would be nothing wrong with that. But the minimum altitudes all along the approach would still apply. It would take a little fore planning to assure that a VNAV path would not take you below any of those altitudes. In the G1000, the VNAV function prior to WAAS was predicated on the altimeter setting, so WAAS is really only removing the margin of error for say an incorrect altimeter setting or an uncalibrated ADC.
 

CoffeeIcePapers

Well-Hung Member
Legal or not, if I am shooting a VOR approach, I am going to have the VOR as the active CDI and leave the GPS as the bearing pointer.
 
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