Fell into the same procedural hole, twice in a row...

Bill Watson

Bill Watson

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I fumbled my last two LPV approaches having forgotten a WAAS specific ‘feature’ in the avionics (G430 and exp GRTs).

Flying into KAGC I was cleared for the RNAV 28 approaching on a heading of 360 directly to KAGC. The controller gave me a ‘fly direct to LENLE (the FAF). Well as I should have remembered, if you direct-to a waypoint or leg of the approach, other than an IAF, while you are on the airport side of the FAF, the approach suspends. I know that, but have forgotten over time because it so rarely happens to me.

To make it worse, I hit the CDI to unsuspend it and then got procedurally lost. I brute forced things back to normal by reloading the approach and just flying the heading to the FAF knowing that I would get a series of vectors to set me up for the intercept.

Same thing happened on a proficiency approach into Roanoke. Not sure how I set it up for the suspend but I know Roanoke is no place to be screwing up an approach so I just aborted and moved on.

I wish controllers would avoid using the FAF instead of vectors for setting up a vectors to final. But I should have known better and it was a good refresher on WAAS approach quirks.

Thanks for letting me share.


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That doesn’t even sound like a legal clearance. A 90 + degree intercept at the FAF? ATC isn’t supposed to send an an aircraft direct a FAF unless it’s also a IAF and a HILPT is to be conducted.

You can get vectored to intercept a fix outside the FAF and inside the IF (30 degrees) or if RNAV, given direct the IF (90 or less). Direct the FAF and cleared for the SIAP shouldn’t happen.
 
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Maybe he requested the visual?

If I’m getting vectored I’ll go into heading mode, activate vectors to final, confirm I’m loaded and acitivsted, arm the approach mode when I hear “cleared the approach”

Not sure the GRT, but many eHSI/efis you don’t have to select the vloc/gps mode on a GNS/GTN, you just select the nav mode on the eHSI.
 
James331 said:
Maybe he requested the visual?

If I’m getting vectored I’ll go into heading mode, activate vectors to final, confirm I’m loaded and acitivsted, arm the approach mode when I hear “cleared the approach”
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That’s about the only way you could get cleared from the FAF. OP said cleared for the RNAV 28 though.
 
My error. I wasn’t ‘cleared for the approach’ at that point. I was being vectored for the RNAV 28.

Normally I would be vectored with a series of headings. In this instance the controller told me to “Turn direct LENLE”. I had the approach loaded so I hit FPL, scrolled down to LENLE and selected it for a direct to. That was my mistake or at least I was ignoring the fact that given my position, that would put the approach in ‘suspend’ mode. From there I fumbled until I decided to reload the approach.

I think what I could have done is simply ignored the ‘suspend’ mode and flew on until I was given the steering vectors to come around and intercept the final approach course outside of LENLE. Given the first steering vector I would have selected heading mode on the GRT, dialed in the vector and flown it. I believe that once outside of LENLE, the approach on the G430 would have automatically switched back into sequence mode.

If I had selected vectors to final, all would be good. Since I normally load an IAF per advice from the various training guides, I would have also activated the leg to LENLE sometime before the final intercept. Vectors to final would have eliminated some extra button pushing.

Going forward, I may start using Vectors to Final when being vectored to final - keeps it simple. Reflecting back, I never get a “fly to (intermediate fix XXXXX)”, I just get vectors.

(I was IMC at the time and hand flying but I fly and push buttons just as if the AP was engaged to keep things consistent)


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Walboy said:
So, in retrospect, how should you have set up the approach given ATC's instructions?

Could you have flown direct as instructed and then once vectors began activate the leg ending at LENLE?
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Yes


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Bill Watson said:
Reflecting back, I never get a “fly to (intermediate fix XXXXX)”, I just get vectors.
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There are some airports where you always get direct to an intermediate fix unless you ask for something else.


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Once in the weeds so to speak would have “activating leg” been appropriate?? Since you were on the “airport side” we you getting vectored for the procedure turn??
 
Bill Watson said:
My error. I wasn’t ‘cleared for the approach’ at that point. I was being vectored for the RNAV 28.

Normally I would be vectored with a series of headings. In this instance the controller told me to “Turn direct LENLE”. I had the approach loaded so I hit FPL, scrolled down to LENLE and selected it for a direct to. That was my mistake or at least I was ignoring the fact that given my position, that would put the approach in ‘suspend’ mode. From there I fumbled until I decided to reload the approach.

I think what I could have done is simply ignored the ‘suspend’ mode and flew on until I was given the steering vectors to come around and intercept the final approach course outside of LENLE. Given the first steering vector I would have selected heading mode on the GRT, dialed in the vector and flown it. I believe that once outside of LENLE, the approach on the G430 would have automatically switched back into sequence mode.

If I had selected vectors to final, all would be good. Since I normally load an IAF per advice from the various training guides, I would have also activated the leg to LENLE sometime before the final intercept. Vectors to final would have eliminated some extra button pushing.

Going forward, I may start using Vectors to Final when being vectored to final - keeps it simple. Reflecting back, I never get a “fly to (intermediate fix XXXXX)”, I just get vectors.

(I was IMC at the time and hand flying but I fly and push buttons just as if the AP was engaged to keep things consistent)


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Click to expand...

I’d still LOAD with the predicted IAF, as it will load ALL the waypoint, but once they give you a vector, go heading mode and activate VTF, arm approach mode on the AP once cleared.
 
Bill Watson said:
My error. I wasn’t ‘cleared for the approach’ at that point. I was being vectored for the RNAV 28.

Normally I would be vectored with a series of headings. In this instance the controller told me to “Turn direct LENLE”. I had the approach loaded so I hit FPL, scrolled down to LENLE and selected it for a direct to. That was my mistake or at least I was ignoring the fact that given my position, that would put the approach in ‘suspend’ mode. From there I fumbled until I decided to reload the approach.

I think what I could have done is simply ignored the ‘suspend’ mode and flew on until I was given the steering vectors to come around and intercept the final approach course outside of LENLE. Given the first steering vector I would have selected heading mode on the GRT, dialed in the vector and flown it. I believe that once outside of LENLE, the approach on the G430 would have automatically switched back into sequence mode.

If I had selected vectors to final, all would be good. Since I normally load an IAF per advice from the various training guides, I would have also activated the leg to LENLE sometime before the final intercept. Vectors to final would have eliminated some extra button pushing.

Going forward, I may start using Vectors to Final when being vectored to final - keeps it simple. Reflecting back, I never get a “fly to (intermediate fix XXXXX)”, I just get vectors.

(I was IMC at the time and hand flying but I fly and push buttons just as if the AP was engaged to keep things consistent)


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Click to expand...

You shouldn’t have gotten direct LENLE either.

http://masterflight.aero/2014/05/24/atc-breaking-rnav/
 
I'm training, it's load to an expected IAF then activate VTF which happens most of the time here. To solve this particular issue, I'm thinking hitting the direct to button then entering the waypoint, enter, enter, would not have activated the approach and allowed a little time to think rather than scrolling on FPL and activating. The only issue with VTF is that you can lose the initial approach fixes. My instructor is big on requesting what I want for an approach including whether I want VTF or an IAF, no guessing involved.

My question is that had ATC left you on that clearance, would the LPV approach GP have activated because you would be turned inside the FAF by the time you made the turn.

Edit: Just saw velocity's post, good point, unable is probably the proper response, turning a few degrees before the FAF to fudge it may not be good either.
 
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You want to load the whole approach not just vectors to final. Sometimes they will say vectors to final then give you a waypoint that was deleted by the procedure. Annoying but it is what it is
 
It has been all said, direct to the FAF on an RNAV approach is not a valid clearance. I would have not accepted the clearance. "Unable, I can accept a vector to the final approach course". Depending on your GPS navigator and in some instances the software version, direct to the FAF on an approach will generate an error message indicating that the approach mode has been cancelled.
 
James331 said:
Sounds like they just don’t understand how and why to use VTF.
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Nobody would have a problem if the controller just gave vectors to final after saying vectors to final. Instead some controllers say “vectors to final” then give a “direct to fix”. So pilots have to have 530 hacks to make it work.

It’s easy to say unable, and if you tangle yourself that’s probably best. But when you have somewhere to go, it’s frustrating and tempting to make it work. Unseasoned Pilots may need extra time and predictable planning.
 
Still when they give you a vector and your close to the approach VTF is good to go 95% of the time.

If you’re still a ways out, I’d keep it loaded to the IAF
 
Good thread @Bill Watson . Reminds me of what Auric Goldfinger said to James Bond in the movie Goldfinger. Mr Bond, they have a saying in Chicago: "Once is happenstance. Twice is coincidence. The third time it's enemy action." If ATC does it to you again you must fire back with “unable.”
 
As others have said they can't clear you direct to LENLE, but they could clear you direct to MILKE (IF) at an angle up to 90 degrees and at a "compatible" altitude (require descent not greater then 300 feet per mile. That would be not higher than 4,800. Where there is a stepdown fix between the IF and the FAF they can clear you direct to such a stepdown fix at an angle not greater than 30 degrees and at an altitude compatible with the procedure. The fact that some controllers do not know these rules is, alas, the way of air traffic control.
 
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aterpster said:
As others have said they can't clear you direct to LENLE, but they could clear you direct to MILKE (IF) at an angle up to 90 degrees and at a "compatible" altitude (require descent not greater then 300 feet per mile. That would be not higher than 4,800. Where there is a stepdown fix between the IF and the FAF they can clear you direct to such a stepdown fix at an angle not greater than 30 degrees and at an altitude compatible with the procedure. The fact that some controllers do not know these rules is, alas, the way of air traffic control.
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I’m thinking that technically it was an ‘acceptable instruction’ because it wasn’t issued as part of a ‘cleared for the approach’. But perhaps not. In any case, I knew from previous experience that I was only being steered for a series of vectors before being cleared for the approach after getting a vector to 310 or less outside of the FAF.

I’m thinking that a clearly stated rule for ATC is to never issue a clearance or issue a direct-to instruction for the FAF on RNAV approaches.

I wasn’t aware of the altitude limits. On this particular approach I had been cleared to descend down to the usual altitudes, but I told them I need to stay out of the icy clouds as longs as possible so I would be delaying my descent as long as possible. There was no response to that and I did as stated. That part worked out fine.


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Bill Watson said:
I’m thinking that a clearly stated rule for ATC is to never issue a clearance or issue a direct-to instruction for the FAF on RNAV approaches.
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It's improper, whether considered to be a clearance or an instruction.
 
They can send you direct LENLE but “cleared visual approach runway 28” should follow.
84643E4C-0041-4C0A-B585-ADCB408F1970.jpeg
 
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James331 said:
I’d still LOAD with the predicted IAF, as it will load ALL the waypoint, but once they give you a vector, go heading mode and activate VTF, arm approach mode on the AP once cleared.
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Is there a way to do that without reloading the approach?
 
noahfong said:
Is there a way to do that without reloading the approach?
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You’re ether loading the waypoint or VTF, guess you could direct enter enter to the faf
 
Some good discussion here.... "i like pie" Bookmarking for future retrieval and review
 
aterpster said:
Which is not an instrument approach procedure. And, a visual approach does not have a FAF.
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Correct but the controller can still clear an aircraft direct to a FAF and the clear them for the visual. Just saying in the OP’s case, that’s the only way he would be allowed direct LENLE.
 
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Velocity173 said:
Correct but the controller can still clear an aircraft direct to a FAF and the clear them for the visual. Just saying in the OP’s case, that’s the only way he would be allowed direct LENLE.
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Not quibbling with you, rather with this particular ATC procedure.
 
James331 said:
Maybe he requested the visual?

If I’m getting vectored I’ll go into heading mode, activate vectors to final, confirm I’m loaded and acitivsted, arm the approach mode when I hear “cleared the approach”

Not sure the GRT, but many eHSI/efis you don’t have to select the vloc/gps mode on a GNS/GTN, you just select the nav mode on the eHSI.
Click to expand...

There’s a potential little trap in using Vectors to Final for those of us who don’t use it regularly. It’s sort of the same trap I fell into with doing the direct-to LENLE. That is, if you are on the airport side of the FAF, you start getting vectors and then activate vectors to final, the GNS will go into Suspend (waypoint sequencing is stopped).

That’s no problem as long as you accept that without taking action. The GNS will un-Suspend automatically when you get on the right side of the FAF and headed in the right direction.

However if you attempt to unSuspend it by pressing the OBS key, strange stuff happens. The Trescott book tells me that the nearest leg in the flight plan is activated (?). I know that if you press it again, the approach de-activates. I’ve done this or a variation of this multiple times over the years without fully understanding what was going on. It’s relatively rare for me to get vectored around for an RNAV approach on the airport side of the FAF. Happens all the time for the ILS.


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benyflyguy said:
Once in the weeds so to speak would have “activating leg” been appropriate?? Since you were on the “airport side” we you getting vectored for the procedure turn??
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Turns out that by trying to unSuspend the approach by hitting the OBS key a couple of times, I had deactivated the approach.

Yes, activating a leg after doing the unSuspend would have been the right thing to do, but if I was still inside the FAF, the leg would activate but the sequencing would be suspended again. If I knew enough to ignore the suspend, I probably wouldn’t have been in the weeds in the first place.

No, I wasn’t being vectored for the procedure turn, they were just sending me from the airport out to make a 180 turn via a series of vectors, back to intercept the final course. Very standard for my arrival from the south for a landing on 28.

They always offer the ILS but I’ve gotten in the habit of requesting the RNAV because I find the ILS for 28 very ‘lumpy’. If I try to let the AP fly it it always overshoot the final course and then hunts left and right quite a bit. I can almost see the approach controller saying to himself, “oh hell, the RNAV! What’s a fix on it that I can give this guy until I figure this out.... go to LENLE”. If I had stayed with the ILS I would have gotten 3 or 4 vectors turning me around to intercept the final, which would have worked perfectly for the RNAV as well.


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Okay, I got this now. Thanks to everyone for helping me turn this over a few times to get at the problems.

As usual, I found a very specific discussion of this situation in Max Trescott’s GPS and WAAS Instrument Flying Handbook from 2009. On page 126 it reads:

********
Activating a Leg or Vector to Final from Inside the FAF

There is a major gotcha that’s likely to trap experienced GPS users until they understand that WAAS capable GPS receivers operate differently ....(cont)
*********

There it continues to describe the ‘gotcha’ and the ways to avoid it or get out of it once you screw up. It’s a real good read.

Bottom line is that even with the improper ‘direct-to the FAF’ given to me by the controller, I should have recognized how that would be handled by my G430, and by recognizing that, I could have easily avoided getting lost in the weeds.


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