You were uncertain and requested an alternative clearance
I was quite certain of the published procedure i.e. starting at LEKLA, and after ATC would not give descent instructions for the alternative (which sounded pretty dodgy to me, but the comms there was a bit marginal in ELP terms) and gave me LEKLA again, I was obviously happy with that. Quite simple really!
I can see what the part-circles probably are (there is still disagreement here whether they are the “emergency only MSA” (like the MSA circle in the top right of Jepps, or the 2000ft ones on the EGKA plate) or something to be used operationally) but they are not a part of the procedure I was flying, so of no concern to me.
In IMC especially, I fly procedures as published, not fly around the place keeping above some MSA figure. In the case of LFMT R12 you will get killed if you make a mistake.
If you follow a published procedure, laterally and vertically, starting at an IAF, you are safe, and that’s what I do 
I am waiting for a converter program so I can do the movie using the ex-FF KML track file for the subtitles. Often, this record shows up interesting stuff not noticed at the time.
Peter wrote:
I can see what the part-circles probably are (there is still disagreement here whether they are the “emergency only MSA” (like the MSA circle in the top right of Jepps, or the 2000ft ones on the EGKA plate) or something to be used operationally) but they are not a part of the procedure I was flying, so of no concern to me.
Well, you can disagree with what PANS-OPS says explicitly, but that doesn’t make much sense to me. And they are part of the procedure.
I don’t see why you insist calling them “MSA figures” when it has been pointed out several times that the are not. They are TAA figures. You can check the Jeppesen chart legend if you don’t believe me.
chflyer wrote:
The relevant info begins on page 5-4-9 and goes on for several pages.
I would expect that all FAA IR holders would be familiar with this
It would be nice if this were true, but then I would not have much business if pilots would RTFM. I go over this when conducting an IPC and at least half of the pilots don’t understand the material.
Peter wrote:
But as I say it’s another topic. It is easy to fly any proper GPS procedure with a KLN94. There were some oddball ones published which needed a GNS+ but I can’t remember what they were called (multiple entry options on a STAR).
The KLN94 is not certified for RNAV 1 based SID and STAR. They are not in the database. In the US, the KLN94 can not be used to substitute for VOR.
The IAP in question is RNP 12L which is in the database.
I am trying to remember the one I was thinking of but can’t. It was called something like “variations” and it was basically a STAR with maybe 10 parallel tracks, spaced out equally, and you needed a GPS which had them all in the database and you could quickly select them. I saw this many years ago, and it needed at least a GNS430 to get that data. I never saw this at any airport in real life. Even LFPG (which AFAIK owns the monopoly on # of plates) doesn’t show this. It doesn’t relate to this thread.
EDIT: I found LOWW has these, called “transitions”. But not the kind I saw before. Anyway, not relevant.
NCYankee wrote:
In the US, the KLN94 cannot be used to substitute for VOR.
In UK/EU, we are not allowed to substitute VOR anyway: I am talking about final approach segment, we don’t have plates ‘GPS or VOR’
I do recall the main reason why some VOR legs were not supported is that the ‘course-to-fix’ (CF) AIRNC was not being supported by some units, lot of PBN legs these days are coded in ‘track-to-fix’ (TF) which is supported by any IFR GPS: ‘track-to-fix’ (TF) leg has benefit of avoiding magnetic variations creeping into database coding whereas in ‘course-to-fix’ (CF), VOR magnetic variation affects the radial/course
The use of VOR radials & courses in approaches, departures, arrivals or airways was always problematic (the radials needs regular updates for magnetic variations while the magnetic pole moves, the tracks are rigid in space)
I recall this only affect overlay RNAV procedures (pure conventional procedure could be available in GPS !!)
It’s an artificial issue: repainting runway numbers does not affect your landing with VOR final
Airborne_Again wrote:
They are TAA figures. You can check the Jeppesen chart legend if you don’t believe me.
The TAA at EGKA for the RNP 02 would not be acceptable to FAA, as the segment altitudes are not allowed to be below the IAF altitude. The segments also preform the function of being an RNAV feeder route from any airway that passes through the segment. In the US, pilots are expected to descend to the TAA altitude once cleared for the approach. If that were the case at EGKA, one would have to climb to 2200 prior to reaching GODOT in the right base 2000 foot segment. MSA also can’t have any segmentation except using radial segmentation with segments no less than 90 degrees. Also, US charting standards do not permit both an MSA and a TAA to be charted on the same approach chart.
Some of my comments above on the handling of VOR legs may explain why MT505 may not appear in some databases or listed as IAF:
MT505 was lost in that middle at 13nm & 18nm?
Getting Vector-To-Final on this RNP will still keep someone 4deg off…
GPS & VOR plates are here,
A vague guess but I have seen issues of missing GPS data for VOR radials previously
Ibra wrote:
The use of VOR radials & courses in approaches, departures, arrivals or airways was always problematic (the radials needs regular updates for magnetic variations while the magnetic pole moves, the tracks are rigid in space)
In the US, VOR’s are rarely realigned to the more current magnetic variation, so as long as one uses the airway or procedure radial, the course does not move. Each VOR database entry includes the magnetic variation at the time the VOR was installed or the last time it was realigned. It is given a special designation for the magnetic variation termed the declination. GPS systems use the declination value when a VOR is the destination waypoint in leg mode, and anytime OBS mode is used where the navigation is to/from a VOR. That way, the radials line up on a GPS the same as if one is using a VOR for navigation. Some VOR’s have a declination based on the 1960’s magnetic variation epoch and differ by 6 degrees from current values. The same is true for runway designations and conventional procedures using ILS , VOR, or NDB, except that they are updated more frequently. My airport is still using the 1990 (32 years ago) magnetic variation which was 5 W, the current magnetic variation is 8 W.
In the US, VOR’s are rarely realigned to the more current magnetic variation, so as long as one uses the airway or procedure radial, the course does not move
Got it, they do “get serviced” every year around here (lot of money, way more than anyone can imagine plus obvious plates and charts re-printing)
