Hint: there’s a reason they’re wealthy.
nah. Just MORE of a problem.
Ahem…<newbie to POA>
I tried this numerous times in the GTNXi trainer (I know it's not the G1000). I could not get the TAWS to give a warning while coupled to the approach. The red in the terrain did not show up until maybe 10 secs before "impact." If you're zoomed out at all on the 750, it's barely noticeable.
3nm, which really doesn't resolve the red terrain well amongst everything else on the map.
Same here…!
Did the GTN say anything about the terrain? Did you have the Dynon syn viz turned on?
Just to clarify... on the G1000:
The part I’m still having trouble understanding is why someone would even want to fly this approach over the RNAV-E. The Z approach is advertised as a straight-in, but to remain safely clear of the mountain, it’s nearly as steep as the E. There’s nothing that says you can’t fly a straight-in on the E, anyway, it’s just up to whether you can remain stable and maybe meet company op specs, where applicable.
I don't think in this case it would matter. The wording of the notes is specified in 8260.19K. All possible variations of the notes are not listed. This is from a portion of the notes guidance:
I would argue that there is little or no descent below the MDA prior to the mountain that is safe at all, and that WDCHK was created to sell a straight-in that met the vertical constraint of the design, even if it could never safely be met. This is the case regardless of the +V capability of the navigation unit.
The procedure could be safely flown during the day, but one would have to visually avoid the mountain. The visibility to see the airport at WDCHK would require at least 6.3 SM and if not, one needs to remain at the MDA until the 91.175(c) requirements are met. It would certainly be a steep descent and where it was beyond the capability for a straight-in, circling in the pattern would be an option.
I covered this in the earlier disclaimer that there’s a lot of “knowledge” one has to have to avoid the gotchas on instrument approaches. I’ve always been conscious of the +V limitation.
Yes, and those conditions include the visibility required in order to see obstacles. I think the real point is that instrument pilots need to learn that there is no implicit obstacle clearance below the MDA. A VDA and Garmin's +V adaptation of the VDA doesn't change that. Sure, we can make this - and more benign approaches - safer, but there' also a downside to making approaches unusable. Perhaps more of a caution than the current one is in order?
Good set of questions, John. Lately I've been doing a quiz for IPCs and I plan to include a few +V and 34:1 obstacle questions in the next iteration.
So back to an earlier point - at what altitude above is it safe to cross that ridge?
The altitude where you can see you are not going to hit it. Just like less nefarious obstacles. That's why it's NA at night PAPI helps since it provides obstacle clearance and you won't see the PAPI lights unless above the blocking obstacles. That's not just an instrument thing; it applies to VFR flight as well.
Per the chart supplement, the PAPI aren’t useable on the azimuth of the Z approach. The PAPI are still shown on the approach chart inset diagram (ostensibly for general circling, or once established on final), but this important tidbit isn’t noted on the chart itself.
granted I’m not doing mental math, but just looking at the chart it would appear that if you saw the runway at WDCHK, altering course to the right to intercept the extended centerline would give you a pretty clear descent path for a normal, stable descent. What am I missing?
Good questions. It's been a while but I think the first thing I noticed was the entire screen on the 650 was yellow. I asked myself why's the screen yellow. Dynon syn viz is on but I think it was the 650 that clued me in first.
