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Over ten grand on a GTN-650

EGKA could have LNAV+V too, but I cannot check that. You have to load the approach and activate it and only then it will show it it’s “LNAV” or “LNAV+V”.

(Seems some pilots reported “LNAV+V” indication for both runways at Shoreham)

Last Edited by at 07 Sep 12:01

One thing that many forget/don’t know: With a 430W you can fly a normal LNAV approach with a virtual glideslope because Garmin provides the “LNAV+V” feature for those.

No, I don’t think anybody who did any due diligence on the subject forgets that.

Many of us really still don’t “need” GPS approaches all that often. First of all, as Achim often pointed out, most of the “private” IR pilots (i.e. not flying for business reasons regularly), don’t fly many instrument approaches at all. I fly about 15-20 a year, just enough to remain current as per FAA regs. The reason being:

-most of us are based at airfields without an IAP. See yourself, Achim, me, etc. It just has so many advantages being based at a small, GA-only, VFR airfield. Cost being one of them.

-many interesting GA destinations in Europe simply don’t have instrument approaches. Think of the German Islands in the North Sea, think of Zell am See or Saanen in the Alps, think of the Scottish Isles, think of Italian aviosuperfici with a hotel on site, etc. These are the really great GA destinations. The only exceptions really are city trips where often there is a convenient (if sometimes expensive) airport with IFR procedures. But then again, for city trips, GA does often not make sense financially and are better served by airline or by train.

-and even when the destination does have an instrument approach, let’s face it, very often, the weather will be VMC (we don’t often fly to places where the weather is foul) and then many prefer the visual, at least when the IAP would involve flying all the way around to the other side of the airport. This can often cost you 20 minutes over flying a quick visual. And these 20 minutes can be VERY valuable, both in terms of fuel / hobbs time and in terms of sheer TIME. After all, when we fly somewhere, we try to maximize the time we have at our disposal on the ground.

So if you then take these 20 instrument approaches per year, let’s say maybe 5 of them are in IMC. In these 5 cases, there will likely be 3 airports which do have an ILS. So there is a total of maybe 2 “required” GPS approaches. I deem it very unlikely that in there two cases, the weather will be below LNAV minima (usually about 400 feet), but above LPV minima (usually 250 feet). THAT however would be the only “real” utility aspect of WAAS.

All else is IMHO just “gadgeteritis”, or possibly a little bit of convenience (not having to calculate a glidepath, but just lazily following the needle).

Last Edited by boscomantico at 07 Sep 12:14
Frankfurt (EDFZ, EDFE), Germany

Well, of course there’s a lot of truth in what you write, but if you take that concept a bit further none of us needs an airplane to go anywhere anyway ;-) Or did you install the Beringer brakes because you really “need them”? I did it because I like modern equipment, enjoy dealing with these upgrades.

But I also prefer RNAV approaches over ILS, because they are more precise and safer IMHO.

The GNS43W offers other interesting features: automatic holding entries and procedure turns for example and a six times faster processor and better GPS receiver. The fast processor makes it possible to fly real tracks on the GNS screen … not possible with the ormal 430 hat is simply too slow. Do i need it? No. Do I like it? Yes.

I can understand every pilot who says “for the 5 real approaches in IMC” i will not invest that kind of money. Absolutely.

(I fly about 30 training approaches/year – and maybe 5-10 real ones. So what)

Last Edited by at 07 Sep 13:13

carlmeek

If you’re doing the panel from scratch anyway, the GTN750 is vastly superior to the GTN650. Really, they designed the interface for the 750, then squeezed it into the 650.

EGTF, LFTF

Alexis wrote:

With a 430W you can fly a normal LNAV approach with a virtual glideslope because Garmin provides the “LNAV+V” feature for those.

But you still need to use LNAV minima, which themselves assume a 0.3nm tramline FSD, so are generally quite high.

Glideslope comes into its own in the last 200’, not the first 1400. For that purpose, LNAV+V has no bearing.

EGKB Biggin Hill

Glideslope comes into its own in the last 200’, not the first 1400. For that purpose, LNAV+V has no bearing.

That’s true only if you are doing a zero-zero approach using an ILS (or some synthetic ILS). One is supposed to be visual at 200ft (or so) so the glideslope is very much useful before 200ft.

But even CAT3 airliners don’t follow the GS all the way down. They switch to a RADALT at something like 150ft, and only the LOC remains being tracked (which is one reason why the LOC transmitter is at the far end of the runway).

I would say LNAV+V is very useful because it is available at far more locations than LPV.

Of course the 750 is much better than the 650, but it is also much bigger and much more expensive.

Personally I would not want an IFR plane with a GNS430/W or a GTN650 or IFD440 as the only GPS. They are tiny boxes with near-useless moving maps. All these boxes need an “MFD” like a GNS530/W, GTN750, or if you like “retro” one of the old style MFDs which aren’t fashionable in light GA anymore (there is a thread on MFDs here somewhere). OTOH on a kitplane one will probably flying mostly with an Ipad velcroed to the panel, and the panel mount GPS will be mainly an autopilot controller for approaches.

The fast processor makes it possible to fly real tracks on

Real tracks?

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

All these boxes need an “MFD” like a GNS530/W, GTN750,

Or if you really don’t have the panel space, an iPad on your knees.

Last Edited by Noe at 07 Sep 15:48

Yeah… until you accidentally touch it and then you get the “Airbus pilot” expression of WTFIIDN (that the f—k is it doing now)

IMHO all kit required to fly a plane should be in the panel, not on your knees and with batteries running down etc. It is a consequence of European ripoff copyright policies on mapdata that so many of us fly with tablets to supplement navigation etc.

Administrator
Shoreham EGKA, United Kingdom

Real tracks?

The WAAS models have a much faster processor so you see the airplane move on the screen in real time, not the case with the old unit.

Personally I would not want an IFR plane with a GNS430/W or a GTN650 or IFD440 as the only GPS.

Absolutely. Mine drive a large glass cockpit with two huge screens. They actually are the “only” GPSA, but you have the route/approach not only displayed inside the HSI but also on a large MFD,

I would also not fly approaches wit the iPad. My iPad is only a backup during the approach.

Last Edited by at 07 Sep 16:00

Peter wrote:

IMHO all kit required to fly a plane should be in the panel, not on your knees and with batteries running down etc.

Yes, but given a situation where there’s no space for a large display in the cockpit, I’d prefer to have the option to have the iPad on my knees / RHS, rather than just having the tiny display.

It is a consequence of European ripoff copyright policies on mapdata that so many of us fly with tablets to supplement navigation etc.

So how come the US are big users of tablets too?

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