Interesting Approach Plates

[michal 44]

That approach into KMTN... military jet only.

Nothing on the approach plate that would suggest it is a military-only approach and as a pilot I have to go by what info is in front of me. The airport is not restricted to military traffic only.

The main reason it is not in G1000 is that Garmin doesn't support final approach course being a curve.

[WarpD 824]

Yeah... no... it's not in the raw database either... which doesn't care about Garmin one bit.

[RedSpinnaker 35]

Yeah... no... it's not in the raw database either... which doesn't care about Garmin one bit.

 

The VOR/DME or TACAN Z RWY 15 into MTN is not a military only procedure. I don't know why it's not in the raw database, but that doesn't preclude it being available for civilian use.

 

Without doing more digging, the only thing that immediately comes to mind is AC 90-108 - Use of Suitable Area Navigation (RNAV) Systems on Conventional Routes and Procedures which is what allows using RNAV (GPS) in lieu of DME. The language has made it into the AIM, specifically 1-2-3-c (Note: 4):

 

Pilots may not substitute for the NAVAID (for example, a VOR or NDB) providing lateral guidance for the final approach segment.

 

MTN is a rare approach (with an arc as the final approach segment). Here's my blind leap (which may be incorrect)...Since RNAV/GPS is being used in lieu of DME, and DME is what is providing lateral guidance on the final approach segment, it's not authorized.

 

This still doesn't necessarily explain why it's left out of the raw database. It's been awhile (years) since I've dug into RTCA specs & requirements. I'm not sure if there is a database flag that prevents an approach from being flown until certain sensors are present (i.e. what if I'm in a a/c WITH a separate DME, and want to display an approach overlay for SA?). Perhaps they don't include it in the database to prevent someone using the approach in GPS mode when it's obviously not authorized due to the final segment?

 

Don't know.. spitballing here. Would need more time to dig deeper.

[ExNusquam 11]

Yeah... no... it's not in the raw database either... which doesn't care about Garmin one bit.

The VOR/DME or TACAN Z at KMTN isn't in any nav databases because it doesn't conform to ARINC rules. IIRC, you can't code Arc-Fix (AF) path terminators on the final approach segment (for a non-precision inside the FAF). 

 

Here's some of my favorites:

How to fail a checkride: KROW HI-ILS RWY 21

Using a Localizer at a different airport: KNZY LOC/DME-A

5-Mile visibility required for LNAV/VNAV mins: KTVC RNAV (GPS) RWY 08

The steepest descent gradient I've seen in CONUS: KDVT RNAV (GPS)-B (there's a reason it's circling only!)

[RedSpinnaker 35]

The steepest descent gradient I've seen in CONUS: KDVT RNAV (GPS)-B (there's a reason it's circling only!)

 

Stepping out of CONUS...and a non-circling... I see your 6.8 degrees, and raise you 9.3 degrees:

 

VNKT VOR DME RWY 02

 

BTW: Thanks for the ARINC clue... Didn't think about encoding fixes in the database...

[ExNusquam 11]

 

 

Stepping out of CONUS...and a non-circling... I see your 6.8 degrees, and raise you 9.3 degrees:

That's actually not 9.3°...its 9.3%, which works out to only 5.3°. Interestingly, the Nepal plate you provided lists this as 5.5°, but the Jepp lists it as 5.3°, which matches my math. Additionally, from 3.0 DME to the runway you intercept the standard 3.0°.

[ViperPilot 81]

The steepest descent gradient I've seen in CONUS: KDVT RNAV (GPS)-B (there's a reason it's circling only!)

I think I have it beat with the KWHR plate I posted, at 7.9°. This was a R/W Approach, when Rocky Mountain Airways was using the Dash-7...

 

http://www.airfields-freeman.com/CO/Airfields_CO_NW.htm

 

Alan  

[Alpha Floor 237]

ExNusquam, great plates you got there! I will try them out with the 777 and see how it goes, what do you think?

 

 

 

How to fail a checkride: KROW HI-ILS RWY 21

 

Or how to learn the difference between "at or above", "at or below" and "at"

 

 

 

Using a Localizer at a different airport: KNZY LOC/DME-A

 

Someone must have accidentally landed at San Diego.

 

 

 

5-Mile visibility required for LNAV/VNAV mins: KTVC RNAV (GPS) RWY 08

 

But why? What's the point?

 

 

 

The steepest descent gradient I've seen in CONUS: KDVT RNAV (GPS)-B

 

So if your Vapp was, say, 140kt, what would the descent rate be? Something like 1900 ft/min I calculated.

[RedSpinnaker 35]

That's actually not 9.3°...its 9.3%, which works out to only 5.3°. Interestingly, the Nepal plate you provided lists this as 5.5°, but the Jepp lists it as 5.3°, which matches my math. Additionally, from 3.0 DME to the runway you intercept the standard 3.0°.

 

You're right...Damn attention to detail after a bottle of wine...

[ExNusquam 11]

 

 

But why? What's the point?

Long answer short, a non-temperature compensating Baro-VNAV system will fly a shallower glide-path on cold days, and the procedures are designed to provide safe obstacle clearance even on the average coldest day of the year for that airport. I'm guessing one of the many towers near the final course is close enough to final to necessitate a DA that's 1359' above the threshold. The visibility requirement is high so you can actually see the runway at that altitude. 

 

 

 

So if your Vapp was, say, 140kt, what would the descent rate be? Something like 1900 ft/min I calculated.

6.8°=721.1 ft/NM. 

 

(721.1 ft/1 NM) * (140 NM/60 Min)

NM cancel. Answer should be 1682.6 ft/Min.

[MarkW 1,491]

The fact that there is no runway number in the title of the approach should indicate to you that this is a circling approach, which means that nobody is expected to be able to line up with or descend for any particular runway with normal maneuvers directly from this approach. What you are actually supposed to do is enter a circling maneuver, a visual traffic pattern, for one of the runways upon sighting the airport.

 

Thanks for this.  I have tried this several times and never could figure out how you are supposed to make the runway.   The circle makes it much easier even if you overfly the field the enter the pattern for the near end of the runway.

[michal 44]

 

 

Here's one from the old Avon STOLPort near Vail, CO...

This airport has been closed long time ago.

[Paraffin 2,197]

Thanks for this.  I have tried this several times and never could figure out how you are supposed to make the runway.   The circle makes it much easier even if you overfly the field the enter the pattern for the near end of the runway.

 

Or, you could ignore the way it's done in real life, and take it as a challenge in a light GA plane just for fun.

 

Hint: airspeed minimum and then cross-controls (kick rudder and opposite aileron) for the quick drop in altitude. It depends on the model you're flying though, and in which sim version. Not all will model this. You can even "cheat" and use something like a Pilatus Porter with beta range for standing on the prop for the altitude drop.