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which procedure turn?

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wsh View Drop Down
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    Posted: 09 Feb 2018 at 6:30pm

a couple of weeks ago I was flying approaches at Rotterdam (EHRD) airport.

For one approach I asked to do the full approach including procedure turn and did it on autopilot in GNSS mode.

I was surprised to see that the IFD540 chose to do the procedure turn for cat c & D aircraft (which is a bit larger turn obviously for higher speed).

How can I see and know what procedure the IFD will chose?

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Post Options Post Options   Thanks (0) Thanks(0)   Quote wsh Quote  Post ReplyReply Direct Link To This Post Posted: 09 Feb 2018 at 6:39pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DavidBunin Quote  Post ReplyReply Direct Link To This Post Posted: 10 Feb 2018 at 11:20am
That is interesting.  I suspect the real answer is that it is doing neither.  The procedure turns I am used to in the United States are all a 45° turn from the approach course.  In this case, that would be a heading of 282° which is between the 273 and 291 shown on your chart.

While I am far from an expert, I don't recall having different procedure turns for aircraft categories on my NOAA approach plates.

With any luck, a more experienced instrument pilot will also reply.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mfb Quote  Post ReplyReply Direct Link To This Post Posted: 10 Feb 2018 at 12:12pm
In the US you can do anything you want to accomplish a course reversal (procedure turn), as long as you stay in the protected airspace.  That airspace is defined by the US Standards for Terminal Instrument Procedures (TERPS). I'm sure that the TERPS accounts for aircraft speed, but I have never seen a specific differentiation between category A, B, C, and D aircraft.

I have no idea if European standards are different from the US ones.

I suspect that David is correct. The IFD is simply doing a generic course reversal which stays in the protected TERPS airspace. It's probably not trying to follow a specific line on a chart. But that's just a guess.

Mike

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Post Options Post Options   Thanks (0) Thanks(0)   Quote AviSteve Quote  Post ReplyReply Direct Link To This Post Posted: 12 Feb 2018 at 10:22am

Historically, in cases where there were different paths for different categories of aircraft, Jeppesen would code the database for the highest category of aircraft.  That's why you're seeing the larger procedure turn.  For several years, however, they have been adding the differing paths as separate transitions, using trailing numerals to provide a distinction in the name.  For instance, at Townsville airport in Australia, the VOR/DME19 approach has a transition named "TL" having different paths for A/B and C/D categories.  In that case, the C/D transition is named "TL1" and the A/B transition is named "TL2".

For whatever reason, Jeppesen hasn't coded every one of these kinds of approaches with separate transitions.  I asked our contacts at Jeppesen specifically about the Rotterdam ILS06 approach and they have confirmed that they will add the cat A/B transitions in cycle 1804.  They will also add an A/B transition for the VOR/DME 06 approach.
Steve Lindsley
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Post Options Post Options   Thanks (0) Thanks(0)   Quote paulr Quote  Post ReplyReply Direct Link To This Post Posted: 12 Feb 2018 at 6:25pm
Thanks, Steve. I appreciate you being willing to jump in and give an engineering-based answer, and even more so that you went to Jepp to get them to fix the issue. May your reign be long.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote wsh Quote  Post ReplyReply Direct Link To This Post Posted: 15 Mar 2018 at 3:04am
Well done...

Can you also ask them to look into the ROT 1R approach?
The autopilot will not fly this onecorrectly as it will overshoot the turn onto final.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AviSteve Quote  Post ReplyReply Direct Link To This Post Posted: 15 Mar 2018 at 9:55am
Originally posted by wsh wsh wrote:

Well done...

Can you also ask them to look into the ROT 1R approach?
The autopilot will not fly this one correctly as it will overshoot the turn onto final.

It looks OK to me in the database.  As approaches go, it's about as plain vanilla as you can get.

What's your 429 and 232 config?  Is your autopilot flying roll steering?  If so, at what point does it switch to VLOC?  Any chance of you getting video of it happening?
Steve Lindsley
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jhbehrens Quote  Post ReplyReply Direct Link To This Post Posted: 15 Mar 2018 at 6:29pm
Perhaps Jeppesen incorrectly coded EH241 as a fly over instead of a fly by waypoint?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote luchetto Quote  Post ReplyReply Direct Link To This Post Posted: 15 Mar 2018 at 6:41pm
Steve your question is raising my interest as I have reported more than once that my KFC150 ap mostly turns into the wrong direction when intercepting the final approach course during a vectored approach. Our interception angle is usually less than 30 degrees. the gps vloc switch happens extremely late so that I end up switching manually.

I never understood why sometimes it turns correctly into the final approach course and the next time it turns away from it.
Your remarks about the settings is raising my interest, could this be at the source of my problems?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AviSteve Quote  Post ReplyReply Direct Link To This Post Posted: 15 Mar 2018 at 9:46pm
Originally posted by jhbehrens jhbehrens wrote:

Perhaps Jeppesen incorrectly coded EH241 as a fly over instead of a fly by waypoint?
That was my first thought too, but I checked the raw navigation database and it's not flyover.
Steve Lindsley
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AviSteve Quote  Post ReplyReply Direct Link To This Post Posted: 15 Mar 2018 at 10:53pm
Originally posted by luchetto luchetto wrote:

Steve your question is raising my interest as I have reported more than once that my KFC150 ap mostly turns into the wrong direction when intercepting the final approach course during a vectored approach. Our interception angle is usually less than 30 degrees. the gps vloc switch happens extremely late so that I end up switching manually.

I never understood why sometimes it turns correctly into the final approach course and the next time it turns away from it.
Your remarks about the settings is raising my interest, could this be at the source of my problems?
If the autopilot is using deviations, I would expect it to turn away from final when you're outbound on a course reversal.  But if you're inbound on a vectors to final, and you are on course to intercept the active leg, I wouldn't expect it to turn the wrong way.

It's unlikely that your settings are the source of the behavior you're reporting, though.
Steve Lindsley
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AviSteve Quote  Post ReplyReply Direct Link To This Post Posted: 16 Mar 2018 at 9:47am
Originally posted by luchetto luchetto wrote:

Steve your question is raising my interest as I have reported more than once that my KFC150 ap mostly turns into the wrong direction when intercepting the final approach course during a vectored approach. Our interception angle is usually less than 30 degrees. the gps vloc switch happens extremely late so that I end up switching manually.

I never understood why sometimes it turns correctly into the final approach course and the next time it turns away from it.
Your remarks about the settings is raising my interest, could this be at the source of my problems?
Can you post some specific examples of approaches where the autopilot turns away from final and some other examples where it turns the correct way?
Steve Lindsley
Avidyne Engineering
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Post Options Post Options   Thanks (0) Thanks(0)   Quote luchetto Quote  Post ReplyReply Direct Link To This Post Posted: 16 Mar 2018 at 3:15pm
Steve, I don‘t have videos of it but I have experienced this behaviour multiple times on the ILS 14 approach into LSZH.
I am usually coming from the south on the kelip 1 golf arrival and then I get vectored. The final heading I get is 110. The AP is in heading mode with APP armed. Instead of turning right the airplane turns left. This happens most of the times but not always that‘s why I don‘t understand it. The only difference might be my altitude as Zurich Arrival has a tendency to keep GA too high.
What drives my crazy is that the few times it works I have no indications why.
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