Flying an approach to hold reversal with an IFD navigator

[Initial Fix]

I’m sure this is operator error. Let’s dig in.

I am flying a new to me Avidyne IFD440 connected to a KFC-200 with a G5 HSI and GAD 29 in my bonanza. I still have the KFC-256. While getting used to the system in VFR, twice now when flying an approach to an initial fix that is also a hold and course reversal, the plane turned to the final course and not the depicted hold entry on the IFD (barber pole on the IFD). The IFD did show the hold entry as the next waypoint sequence. The selected approach was to the hold reversal fix and not setup as vectors. I was able to catch this both times as the turn was away from protected airspace, and hand fly the hold entry, I let the IFD fly the rest of the approach.

For an example flying from the south to the RNAV 7 at Rochelle (RPJ) and direct to BATBE, the IFD took me to BATBE but turned to the right to the final not into the hold reversal (a left turn for those playing along at home). A parallel entry was shown on the IFD via the barber pole course line, but it still turned to the final.

I think this is a gotcha with the timing of engaging approach mode on the autopilot. Do I engage approach mode before the hold reversal or after? Or is there something else I’m missing?

 

[TommyG]

Is this with GPSS activated?

 

[Radar Contact]

My SOP from flying a ton of coupled approaches with the IFD is to not engage approach mode on the A/P until inbound on the final approach course when a reversal is present. Give it a try and see if that fixes it. Good luck!

 

[Initial Fix]

My SOP from flying a ton of coupled approaches with the IFD is to not engage approach mode on the A/P until inbound on the final approach course when a reversal is present. Give it a try and see if that fixes it. Good luck!

Thanks Kevin, I’ll give that a try.

 

[RussR]

If I understand your sequence of events properly, it is almost 100% likely that engaging APCH mode when you did is the problem.

I assume you have GPSS on for the majority of the flight. GPSS works through the HDG mode on older autopilots, but only provides lateral guidance.

In order to couple with the GS, you need to be in Approach mode.

But on an older autopilot, when you engage Approach mode (or NAV mode for that matter), you put the autopilot back into what I call "dumb" mode - all it knows is left/right indications from the CDI. It no longer can follow the GPS-directed GPSS track. Since all it knows is left/right from the CDI, it can't fly holding patterns or procedure turns. It just attempts to intercept the inbound course that's selected.

So you can't go into Approach mode until after the holding pattern or procedure turn is complete. I believe the manual will say something similar.

If you don't have GPSS, then your autopilot won't be flying any holds or PTs by itself. You'll have to heading-bug around them.

 

[AggieMike88]

My SOP from flying a ton of coupled approaches with the IFD is to not engage approach mode on the A/P until inbound on the final approach course when a reversal is present. Give it a try and see if that fixes it. Good luck!

Same for me with the Garmin products.

 

[flyingron]

Any chance you were approaching the hold from what would be the standard parallel entry? You'd expect an initial turn toward the "unprotected" side.

 

[Initial Fix]

@RussR - thanks for the additional insight. I have been flying GPSS using HDG mode. I had been practicing to learn the operation with entry’s and holds, but most of the approaches were to a standard T initial and not a course reversal hold, or just ATC vectors. The IFD manual is mostly silent on autopilot operation as they say there are too many combinations to include, especially an older AP like mine.

Any chance you were approaching the hold from what would be the standard parallel entry? You'd expect an initial turn toward the "unprotected" side.

I was thinking the same thing. I want to assume the unit knows which is the protected side and turn correctly. In the example to RPJ RNAV 7, coming from the south east, the IFD was indicating a parallel entry after the fix, and would exit after the reversal. So a left turn into the parallel entry. From Russ and Kevin’s reply, it looks like it’s was operation error on my part, and my process needs to change to engage Approach mode after the final fix.
Link to the approach http://www.airnav.com/depart?http://aeronav.faa.gov/d-tpp/2110/05990R7.PDF

 

[RussR]

From Russ and Kevin’s reply, it looks like it’s was operation error on my part, and my process needs to change to engage Approach mode after the final fix.
Link to the approach http://www.airnav.com/depart?http://aeronav.faa.gov/d-tpp/2110/05990R7.PDF

Not AFTER the Final Approach Fix. It has to be before. You can do it at any point where you're lined up on the final approach "course". In the example procedure, I'd do it after completing the course reversal and getting established on the 071 course, which would be outside of BATBE. That gives the autopilot lots of time figure out the wind correction angle and arm the glideslope circuitry.

Make sure you read the autopilot manual too. It will give some interesting archaic examples, but most of the operation is still usable.

 

[luvflyin]

I was thinking the same thing. I want to assume the unit knows which is the protected side and turn correctly. In the example to RPJ RNAV 7, coming from the south east, the IFD was indicating a parallel entry after the fix, and would exit after the reversal. So a left turn into the parallel entry. From Russ and Kevin’s reply, it looks like it’s was operation error on my part, and my process needs to change to engage Approach mode after the final fix.
Link to the approach http://www.airnav.com/depart?http://aeronav.faa.gov/d-tpp/2110/05990R7.PDF[/QUOTE]

Seeing as how you will be hand or bug flying it until established inbound, you may want to think about maybe altering the way the Navigator handles Parallel Entries. It can get you established on the inbound course sooner after the outbound end 'reversal.' First, there is not a protected and unprotected side. There is the holding and the non-holding side. Roughly about 40% of the protected airspace is on the non-holding side. The Navigator is going to want to do a 'fly-by' of the fix and join the holding course out bound rather than fly-over and paralleling it. Flying over and paralleling will have you closer to the inbound course as you complete the about a 210 degree turn during the reversal. That'll get you established inbound sooner. Read AIM 5-3-8 j. 7. and 8. It discusses at length about the shortcomings of some RNAV navigators and what to do about it. Granted, the 'shortcomings' that could get you outside protected airspace are about fast moving planes, but why not use the techniques discussed to make things easier on yourself?

 

[RussR]

Seeing as how you will be hand or bug flying it until established inbound

Why? Unless we're talking for practice, just leave it in GPSS and HDG mode until inbound.

 

[flyingron]

I can't vouch for the Avidyne, but the GNS480 tells you what hold entry it's making.

 

[luvflyin]

Why? Unless we're talking for practice, just leave it in GPSS and HDG mode until inbound.

Yeah, no reason in particular to hand fly it. He had mentioned that when it happened to him he did hand fly it. In HDG mode you are going to have some 'hands on' action inasmuch as you are going to be twisting the knob to set the bug. I'm just suggesting wait until crossing the Fix to do that. Fly a true 'parallel' entry rather than follow the Navigators suggestion to start the turn early and join the course outbound. That will allow you to get established inbound sooner and gives the autopilot more time figure out the wind correction angle and arm the glideslope circuitry as you mentioned above in post #9.

 

[Radar Contact]

I can't vouch for the Avidyne, but the GNS480 tells you what hold entry it's making.

No knock on the 480 as it was the king for it’s time…the IFD is many times a better piece of equipment and does tell you the entry it’s making.

Yeah, no reason in particular to hand fly it. He had mentioned that when it happened to him he did hand fly it. In HDG mode you are going to have some 'hands on' action inasmuch as you are going to be twisting the knob to set the bug. I'm just suggesting wait until crossing the Fix to do that. Fly a true 'parallel' entry rather than follow the Navigators suggestion to start the turn early and join the course outbound. That will allow you to get established inbound sooner and gives the autopilot more time figure out the wind correction angle and arm the glideslope circuitry as you mentioned above in post #9.

No reason to hand fly or heading fly it. The IFD will nail it. The autopilot just needs to stay in NAV mode until the final approach course is joined. Then, prior to the FAF/GS activate approached mode and snap it off to flare.

Occasionally A/P’s in approach mode (not T but course reversal) will turn inbound vs the reversal. Super important to fly as many conceivable options as possible with different avionics setups in VMC prior to diving in low IMC single pilot situations…in my opinion.

 

[RussR]

No reason to hand fly or heading fly it. The IFD will nail it. The autopilot just needs to stay in NAV mode until the final approach course is joined.

Unless you have experience with his exact setup, I'd say NAV mode isn't going to work, as it won't in most of the older autopilots. He needs to be in HDG mode and have GPSS selected, then the GPS will steer the plane around the hold automatically.

 

[Radar Contact]

Fair enough. Should have said NAV/GPSS depending. Point is to not engage Approach mode till on the FAC and hand or heading bug flying isn’t needed.

 

[Initial Fix]

Thanks guys, I’ve got my head wrapped around the sequence now. I’m going to be away from the plane until next week before getting out to fly.

 

[midlifeflyer]

I can't vouch for the Avidyne, but the GNS480 tells you what hold entry it's making.

I think they all do. Pretty easy to tell even without it on the Avidyne, but here it is.

BTW, in addition to the GPSS vs NAV issue, which seems the most likely, there is one other thought which comes to mind. There are two ways to remove the hold when given direct to an IF for a straight-in approach. One would be to tap the first instance of the IF (before you get there) and remove the hold. The second would be to tap the second instance of the IF and go Direct there. That means if one accidentally taps the second instance and makes it, instead of the first, the active waypoint, you're not going to get that PT.