LOC-DME-E approach in Aspen KASE

[TomAce 78]

Hi

I have been flying three flights to Aspen recently to try the LOC-DME-E to rwy 15 with the CRJ 700. I struggle to capture the GS (111.15 IASE) at 11700 ft at DOYPE. I was wondering if someone could give it a try to check if I am doing something wrong, or if there could be something wrong with the default airport in MSFS? 

 

Best regards,

Thomas

[Herman 1591]

For starters, there's no glide slope to catch as it's a Localizer-DME, not an ILS. It's a non-precision approach, described in FAA's Instrument Procedures Handbook (pg. 4-54) as an "instrument approach based on a navigation system that provides course deviation information but no glidepath deviation information. For example, VOR, TACAN, LNAV, NDB, LOC..." A look at the minima table confirms that. That 6.59 degree descent angle to see in the profile is what it takes to make a constant rate descent to the runway from 11,700' at DOYPE. Note that at even 120 knots ground speed and 1,404 fpm rate of descent, your ground prox system will be yelling at you most of the way down. Even worse at 140 ground speed - 1,638 fpm down, which is closer to the usual V_ref.

 

The fun on this one really starts at minimums though. A CRJ is flown to category C minimums which puts you about 3,100 feet above the airport (10,960-7,838). If you didn't see the runway until the minimum 3 miles out, at even a slow 120 KIAS, that's two miles a minute, so a minute and a half to dump 3,100 feet. That takes at least one 360 to do, which is one reason why the approach is "not authorized at night."

[TomAce 78]

1 hour ago, Herman said:

For starters, there's no glide slope to catch as it's a Localizer-DME, not an ILS. It's a non-precision approach, described in FAA's Instrument Procedures Handbook (pg. 4-54) as an "instrument approach based on a navigation system that provides course deviation information but no glidepath deviation information. For example, VOR, TACAN, LNAV, NDB, LOC..." A look at the minima table confirms that. That 6.59 degree descent angle to see in the profile is what it takes to make a constant rate descent to the runway from 11,700' at DOYPE. Note that at even 120 knots ground speed and 1,404 fpm rate of descent, your ground prox system will be yelling at you most of the way down. Even worse at 140 ground speed - 1,638 fpm down, which is closer to the usual V_ref.

 

The fun on this one really starts at minimums though. A CRJ is flown to category C minimums which puts you about 3,100 feet above the airport (10,960-7,838). If you didn't see the runway until the minimum 3 miles out, at even a slow 120 KIAS, that's two miles a minute, so a minute and a half to dump 3,100 feet. That takes at least one 360 to do, which is one reason why the approach is "not authorized at night."

Thanks! I should have seen that this was a non-precision approach. I’m not really used to flying these types of approaches and thought it was the same as rwy 26 LOC to Innsbruck, but have learned the difference now.

 

Thomas

[Herman 1591]

I haven't tried KASE yet in the CRJ, but with all the guidance you get for LOWI compared to KASE, the latter seems harder. It was the site of a notorious Gulfstream III crash in 2001 that I was involved with on one of the edges, so I know it's a challenging place to land IFR.

 

2001 Avjet Gulfstream III crash - Wikipedia

[TomAce 78]

1 hour ago, Herman said:

I haven't tried KASE yet in the CRJ, but with all the guidance you get for LOWI compared to KASE, the latter seems harder. It was the site of a notorious Gulfstream III crash in 2001 that I was involved with on one of the edges, so I know it's a challenging place to land IFR.

 

2001 Avjet Gulfstream III crash - Wikipedia

It’s a really difficult one, for sure.
What I noticed in the CRJ the digits is very difficult to read when you set 5 digits MDA minimum (for KASE it’s 10960). It’s also not possible to set 4 digits DA minimums i think.

[Crabby 28]

1. The loc-dme to KASE is not runway specific.  It is designed to get you into visual of the airport.  Granted, you will probably land on 15, but you could circle to land off that approach to land on 33

2. At DOPYE you should enter into a 6.59 degree descent to minimum.  This is over 2x the normal final descent rate.  Again, this approach is designed to get you into visual acquisition of the airport.

 

Just fly the step down from AJAXX until you hit DOPYE at 11700 then about a 16-1700 fpm from there until minimums or you see the airport.  **I should have said that this descent rate is for planes like the CRJ that have an approach speed of around 140 knots.  Other aircraft will be different.  There is a ground speed to fpm chart on the plate and should always be consulted.