Learning to fly, or thinking of learning? Post your questions, comments and experiences here

Moderator: AndyR

By JPSmith2476
#1550482
last week, we had some pretty challenging weather, I decided to fly an RNAV approach into Gloucester.

I used Garmin Pilot (with a Garmin Glo) and as that isn't certified, I had tuned the ILS.

Garmin Pilot (with the AIP approach plate) put me exactly where I wanted to be, once I had popped out of the cloud.

Using the app (and keeping my eye on the ILS) seemed to be a good way to accomplish my aim which was to use the IR(R) practically.

I had set my minimums to 800ft, but the runway was visible 200 ft above this.

My question is; am I doing anything wrong?

Regards

Jim
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By alexbrett2
#1550490
To fly an RNAV approach, legally you require an aircraft that has an AFM (or in most cases AFM supplement) which specifically allows it.

You're only going to be able to get one of those if you have a certified receiver (e.g. a GNS430 or similar/better).

As such, you were wrong to ask for and accept a clearance for an RNAV approach (I'm presuming you were cleared for it here).

While in reality, it's extremely unlikely your GPS receiver would have been in any significant error, if it doesn't have RAIM (Receiver Autonomous Integrity Monitoring), then a satellite issue could give you an erroneous position without you knowing - given you descended below MSA on the approach, and there are some quite high hills/masts around there, that could have been catastrophic.

Having the ILS tuned in does mean you likely knew the final approach track was correct, although as Gloucester presumably didn't know you were doing it they e.g. could have turned it off or not told you it was broken and misreporting at that point.

I'd suggest going up with an instrument instructor who has RNAV experience in a suitably equipped aircraft for a lesson or two - they can explain all these things in more detail etc...
By johnm
FLYER Club Member  FLYER Club Member
#1550492
That's a wee bit dodgy.

What you did was in effect a self vectored ILS.

What you should have done is fly the procedural ILS using the GPS to help you follow the outbound leg from the beacon and intercept the localiser.

You could then have safely flown down to 300 ft AMSL
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By GrahamB
FLYER Club Member  FLYER Club Member
#1550517
A GNS430 non-W can be approved for Non Precision RNAV approaches, ours was in my previous shareroplane, but:
- you must do the RAIM check before each flight where you intend to use it as the primary nav source.
- you will not get the LNAV+V advisory glideslope where available.
- you must have a database updated to the latest AIRAC cycle (this applies to any set up, of course)

You need the -W model to get the extra features such as autonomous integrity checking, terrain etc. as well as a further STC for PBN approval, which includes LPV approaches.
johnm, A le Ron liked this
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By TLRippon
#1552444
GrahamB wrote:A GNS430 non-W can be approved for Non Precision RNAV approaches, ours was in my previous shareroplane, but:
- you must do the RAIM check before each flight where you intend to use it as the primary nav source.
- you will not get the LNAV+V advisory glideslope where available.
- you must have a database updated to the latest AIRAC cycle (this applies to any set up, of course)

You need the -W model to get the extra features such as autonomous integrity checking, terrain etc. as well as a further STC for PBN approval, which includes LPV approaches.


And an annunciator panel if the 430w is more than 11 inches from the centre of the control column.
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By GolfHotel
#1552527
Paul_Sengupta wrote:
TLRippon wrote:And an annunciator panel if the 430w is more than 11 inches from the centre of the control column.


What if you have a stick?


Theres a lot more than 11 inches from the center of a Cirrus controller to the 430. Will the EFIS count as an annunciator?
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By TLRippon
#1552613
OK, perhaps my shorthand was not clear.

If you have an LPV approved panel fit such as a G1000 or the like then no you don't need a separate annunciator. If you have a steam gauge aircraft and the GNS430W is more than 11 inches from the centre line of the pilot's field of vision on the panel, easily identified IF you have a control column sticking out of it, then you need an annunciator panel to relay the information on the GNS430W display.
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By GrahamB
FLYER Club Member  FLYER Club Member
#1552633
TLRippon wrote:OK, perhaps my shorthand was not clear.

If you have an LPV approved panel fit such as a G1000 or the like then no you don't need a separate annunciator. If you have a steam gauge aircraft and the GNS430W is more than 11 inches from the centre line of the pilot's field of vision on the panel, easily identified IF you have a control column sticking out of it, then you need an annunciator panel to relay the information on the GNS430W display.

Actually, it's a little more than 11 inches for a GNS430W. To quote the UK STC holders:
GAMA Aviation wrote:"Where the GNS-W unit is installed within the 'Normal' or 'Primary Maximum' field of view (as defined in FAA AC23-1311-1C section 15), then the additional annunciators are not required as you can rely on those shown on the GNS unit. To be more specfiic on the field of view, for a typical aircraft flown P1 from the left-seat, then the GNS left edge must be no more than 13.8" to the right of the vertical centre-line through the attitude indicator. For an aircraft flown from the right (SF260 etc), then the right edge of the GNS-W must be no more than 11.8" to the left of the attitude indicator vertical centre-line"

In an AA5, the distance is a gnat's whisker under 13.8 inches (and a bit more under if you take into account the slightly offset seat position), so my CAMO was happy to accept the STC as a pure paperwork exercise, with no need for the annunciator. :)