DrewBlows
Go Tigers!
- Joined
- Jun 25, 2003
- Posts
- 2,031
...continued.
Type three
The third type of WAAS software-generated glideslope you might encounter is called LNAV+V. This is an LNAV approach with advisory vertical guidance. It's essentially a nonprecision approach (LNAV) with an advisory glideslope (+V) that provides vertical guidance so you don't have to worry about things like the step-down fix between the final approach fix and the missed approach point. You can fly the glideslope down to the lowest allowable MDA and, if the requirements for landing aren't met, level off and fly to the missed approach point. If you do meet the requirements for landing, you could remain on the glideslope and ride it all the way to touchdown if it pleases you (and I hope it does).
RNAV (GPS)-generated glideslopes take you to a runway intersection point approximately 1,000 feet past the landing threshold. Of course, you may ignore the vertical guidance if you want and just descend to the MDA, as you would during any nonprecision approach. You won't see "LNAV+V" in the minimums section of an approach chart because these letters don't represent minimums. In your WAAS receiver's approach annunciator window, if the advisory glideslope is available you should see the letters "LNAV+V."
The important point to notice here is that although you may want to fly an approach to LPV minimums or LNAV/VNAV minimums, or use the advisory glideslope (LNAV+V), you can do only what your WAAS receiver allows. And it will allow only the lowest minimums (LPV, L/VNAV, LNAV, or the LNAV+V advisory glideslope) for which it can meet specific accuracy/integrity requirements at the time you are flying the approach. Said another way, you can do only what your WAAS receiver's approach annunciator window shows. If LPV is shown, then you're good for a DA of 700 feet. If LNAV+V is shown, then you're good for an MDA of 860 feet, but can stay on the glideslope to help with step-down fixes.
It appears that the future is not what it used to be, because the future is here. WAAS is what's happening. It's glideslopes galore with WAAS. If you'd like to try a few LPV approaches for yourself, download Garmin's free 500 WAAS simulator online. Visit AOPA's Airport Directory Online to download NACO charts for a specific airport.
Type three
The third type of WAAS software-generated glideslope you might encounter is called LNAV+V. This is an LNAV approach with advisory vertical guidance. It's essentially a nonprecision approach (LNAV) with an advisory glideslope (+V) that provides vertical guidance so you don't have to worry about things like the step-down fix between the final approach fix and the missed approach point. You can fly the glideslope down to the lowest allowable MDA and, if the requirements for landing aren't met, level off and fly to the missed approach point. If you do meet the requirements for landing, you could remain on the glideslope and ride it all the way to touchdown if it pleases you (and I hope it does).
RNAV (GPS)-generated glideslopes take you to a runway intersection point approximately 1,000 feet past the landing threshold. Of course, you may ignore the vertical guidance if you want and just descend to the MDA, as you would during any nonprecision approach. You won't see "LNAV+V" in the minimums section of an approach chart because these letters don't represent minimums. In your WAAS receiver's approach annunciator window, if the advisory glideslope is available you should see the letters "LNAV+V."
The important point to notice here is that although you may want to fly an approach to LPV minimums or LNAV/VNAV minimums, or use the advisory glideslope (LNAV+V), you can do only what your WAAS receiver allows. And it will allow only the lowest minimums (LPV, L/VNAV, LNAV, or the LNAV+V advisory glideslope) for which it can meet specific accuracy/integrity requirements at the time you are flying the approach. Said another way, you can do only what your WAAS receiver's approach annunciator window shows. If LPV is shown, then you're good for a DA of 700 feet. If LNAV+V is shown, then you're good for an MDA of 860 feet, but can stay on the glideslope to help with step-down fixes.
It appears that the future is not what it used to be, because the future is here. WAAS is what's happening. It's glideslopes galore with WAAS. If you'd like to try a few LPV approaches for yourself, download Garmin's free 500 WAAS simulator online. Visit AOPA's Airport Directory Online to download NACO charts for a specific airport.
