Do you have to fly the heading?

[Trogdor]

Riddle me this:

KVCV ILS or LOC 17:

https://aeronav.faa.gov/d-tpp/2110/00794IL17.PDF

You go missed. You fly to 3500. You are before the VOR. Can you now turn to intercept R-269 off of VICTORVILLE or do you have to fly past the VOR first AND then turn to 300 degrees?

Because if you turn before the VOR, 300 degrees takes you no where.

My understanding is you don’t have to fly past the VOR but can turn laterally on a missed as soon as the vertical requirement on the missed has been met. In fact, if I unsuspend my GNS substance pass the “then” statement in the missed, it will sequence me to intercept the radial but not by turning 300 degrees which would again take me to nowhereland.

 

[Tarheelpilot]

Riddle me this:

KVCV ILS or LOC 17:

https://aeronav.faa.gov/d-tpp/2110/00794IL17.PDF

You go missed. You fly to 3500. You are before the VOR. Can you now turn to intercept R-269 off of VICTORVILLE or do you have to fly past the VOR first AND then turn to 300 degrees?

Because if you turn before the VOR, 300 degrees takes you no where.

My understanding is you don’t have to fly past the VOR but can turn laterally on a missed as soon as the vertical requirement on the missed has been met. In fact, if I unsuspend my GNS substance pass the “then” statement in the missed, it will sequence me to intercept the radial but not by turning 300 degrees which would again take me to nowhereland.

No turns prior to the MAP. You can climb anytime. Once passing the MAP and above 3.5 feel free to turn and join the radial. Not required to fly 300 unless intercept from south.

 

[Trogdor]

That was my understanding as well.

 

[Clip4]

Yes, a scenario not designed for a single engine piston that places the aircraft at 3500 ft prior to the VOR.

The procedure anticipates the right turn south of the VOR. I would continue the climb to 6000 and delay the turn until abeam the VOR.

What does the RNAV indicate to do?

 

[MauleSkinner]

Yes, a scenario not designed for a single engine piston that places the aircraft at 3500 ft prior to the VOR.

@aterpster can probably confirm (or deny) this, but I believe the missed is built around and a standard 200 ft/mile climb. This would require almost 2 1/2 miles from DA prior to the turn, putting the turn point slightly beyond the VOR.

If the missed approach is initiated prior to the Missed Approach Point, or if the climb gradient made good is significantly better than the minimum standard, the turn would happen prior to the VOR, but simply taking up a normal intercept heading for the missed approach track would be appropriate.

This missed approach is a little more entertaining if you reach he turn altitude early…
https://www.faa.gov/aero_docs/dtpp/2110/05755IL33.PDF#nameddest=(MKT)
The procedure assumes the turn will be initiated about two miles past the VOR, in which case the airplane’s track will resemble the line on the chart, resulting in a direct entry to the hold.

climbing significantly faster will result in approaching the VOR from the southeast, where a parallel entry would be appropriate. Gets a little sporty if you’re not prepared. But if you realize this ahead of time, simply making the initial missed approach turn to intercept the outbound leg of the hold rather than going to the VOR fist makes it pretty simple.

 

[wilkersk]

..., but I believe the missed is built around and a standard 200 ft/mile climb. This would require almost 2 1/2 miles from DA prior to the turn, putting the turn point slightly beyond the VOR....

Exactly what I was thinking. If you fly to approach minimums, go missed and achieve the minimum climb performance, a 31 degree intercept (heading 300) back to the VCV/269R will keep you out of the higher MSA segment.

 

[MauleSkinner]

Exactly what I was thinking. If you fly to approach minimums, go missed and achieve the minimum climb performance, a 31 degree intercept (heading 300) back to the VCV/269R will keep you out of the higher MSA segment.

MSA really wouldn’t have any bearing on the missed approach from a pilot standpoint.

 

[luvflyin]

Riddle me this:

KVCV ILS or LOC 17:

https://aeronav.faa.gov/d-tpp/2110/00794IL17.PDF

You go missed. You fly to 3500. You are before the VOR. Can you now turn to intercept R-269 off of VICTORVILLE or do you have to fly past the VOR first AND then turn to 300 degrees?

Because if you turn before the VOR, 300 degrees takes you no where.

My understanding is you don’t have to fly past the VOR but can turn laterally on a missed as soon as the vertical requirement on the missed has been met. In fact, if I unsuspend my GNS substance pass the “then” statement in the missed, it will sequence me to intercept the radial but not by turning 300 degrees which would again take me to nowhereland.

You should fly to the VCV 1.7 mile DME Fix before starting the turn. AIM 5-4-21 b.
Read the last sentence

 

[wilkersk]

MSA really wouldn’t have any bearing on the missed approach from a pilot standpoint.

Except if you're south and west of the prescribed missed approach at 6,000'msl and the MSA 11,300'msl, its possible you might find out why they say "via heading 300".

 

[asicer]

You should fly to the VCV 1.7 mile DME Fix before starting the turn. AIM 5-4-21 b.
Read the last sentence

"Therefore, when an early missed approach is executed, pilots should, unless otherwise cleared by ATC, fly the IAP as specified on the approach plate to the missed approach point at or above the MDA or DH before executing a turning maneuver."

That's not pertinent. Look at the approach plate again.

You start the missed approach procedure at 3025MSL and VCV 1.7 DME, just like AIM 5-4-21b says to do. The missed approach procedure says to climb straight ahead to 3500 and then a right turn climb on heading 300deg to intercept VCV R-269. Climbing 475 feet in 1.7 miles corresponds to a gradient of 280ft/mile (420 feet in 1.7 miles at 247ft/mile if S-LOC 17). If you climb on that gradient, you'll be starting your turn right at VCV and you'll eventually intercept R-269. But if you are climbing at 300ft/mile or more you'll be turning before getting to VCV and you'll never intercept R-269 from a heading of 300deg.

 

[MauleSkinner]

Except if you're south and west of the prescribed missed approach at 6,000'msl and the MSA 11,300'msl, its possible you might find out why they say "via heading 300".

If your base assumption is that you can’t stay within the airspace protected for the missed approach procedure you probably shouldn’t be flying IFR.

 

[luvflyin]

"Therefore, when an early missed approach is executed, pilots should, unless otherwise cleared by ATC, fly the IAP as specified on the approach plate to the missed approach point at or above the MDA or DH before executing a turning maneuver."

That's not pertinent. Look at the approach plate again.

You start the missed approach procedure at 3025MSL and VCV 1.7 DME, just like AIM 5-4-21b says to do. The missed approach procedure says to climb straight ahead to 3500 and then a right turn climb on heading 300deg to intercept VCV R-269. Climbing 475 feet in 1.7 miles corresponds to a gradient of 280ft/mile (420 feet in 1.7 miles at 247ft/mile if S-LOC 17). If you climb on that gradient, you'll be starting your turn right at VCV and you'll eventually intercept R-269. But if you are climbing at 300ft/mile or more you'll be turning before getting to VCV and you'll never intercept R-269 from a heading of 300deg.

It’s pertinent to this that the OP said “…My understanding is you don’t have to fly past the VOR but can turn laterally on a missed as soon as the vertical requirement on the missed has been met…” If you meet the altitude requirement before reaching the MAP, you are not supposed to start the turn until the MAP.

 

[Clip4]

You should fly to the VCV 1.7 mile DME Fix before starting the turn. AIM 5-4-21 b.
Read the last sentence

The 1.7 DME is the MAP for the LOC. On an ILS, the missed approach point is that point at which the glide slope intersects the Decision Altitude (DA).

 

[MauleSkinner]

The 1.7 DME is the MAP for the LOC. On an ILS, the missed approach point is that point at which the glide slope intersects the Decision Altitude (DA).

So if you choose to miss early on the ILS, at what point do you initiate the turn?

 

[asicer]

It’s pertinent to this that the OP said “…My understanding is you don’t have to fly past the VOR but can turn laterally on a missed as soon as the vertical requirement on the missed has been met…” If you meet the altitude requirement before reaching the MAP, you are not supposed to start the turn until the MAP.

No, it is not pertinent because the VOR is not the MAP. The MAP is 1.7 miles before the VOR. The problem is that it is possible to fly to the MAP and then turn before the VOR. But if you turn before the VOR, you'll never intercept the radial.

 

[Trogdor]

Correct. I am quite aware you can't turn before the MAP. But the fact is you can reach the MAP and still climb to 3.5k before the VOR and the 300 degree heading is now no good for intercept

Also, the 200ft/nm is a *minimum climb gradient* not a maximum.

 

[midlifeflyer]

Yes, a scenario not designed for a single engine piston that places the aircraft at 3500 ft prior to the VOR.

The procedure anticipates the right turn south of the VOR. I would continue the climb to 6000 and delay the turn until abeam the VOR.

What does the RNAV indicate to do?

At the MAP (runway threshhold), it does a straight ahead climb to 3500' then begins a standard rate turn to the right as it continues to climb, intercepting the R269 whenever it intercept it.

There are a bunch of these. There are two near me. I've seen pilots screw them up by blindly turning to the stated heading rather than using their briefing to realize they may not have to turn that far and checking for the needle indications as they turn. The VCV one is pretty straightforward because the VOR is on the field and you might actually pass it. This one, the ILS 23R at KGSO is worse. In a light piston single, with a 15,000' runway and about 4 miles from the MAP to the VOR a bind turn to 015° will take you far from the radial to intercept. With RNAV it starts the turn to the right, slows down when it reaches a normal intercept - never gets further than 330 with a "normal" 100 KT climb speed.

 

[Clip4]

No, it is not pertinent because the VOR is not the MAP. The MAP is 1.7 miles before the VOR. The problem is that it is possible to fly to the MAP and then turn before the VOR. But if you turn before the VOR, you'll never intercept the radial.

View attachment 100862

As you point out, the procedure does not authorize a right turn to 239 before the VOR to intercept R269.

 

[asicer]

The VCV one is pretty straightforward because the VOR is on the field and you might actually pass it.

However, the unwary pilot referencing only the VOR might see the deflected needle and think they're still in the cone of confusion. Seems that GPS helps a lot here.

 

[Trogdor]

@midlifeflyer That is a good example. So it seems the heading recommendation is advisory depending on aircraft and thus rate of climb.

 

[midlifeflyer]

However, the unwary pilot referencing only the VOR might see the deflected needle and think they're still in the cone of confusion. Seems that GPS helps a lot here.

"Unwary" is a the problem. GPS absolutely helps because activating the missed will fix things, although the difference between the heading on the chart and what the GPS says to do can itself lead to confusion. I think one key is that, while many approach briefings tend to focus on numbers, the Plan View and the 10,000' picture it provides is incredibly important.

i also helps to have been caught by this at least once, preferably in a sim (that's what taught me about it). Or come across a thread like this.

 

[midlifeflyer]

@midlifeflyer That is a good example. So it seems the heading recommendation is advisory depending on aircraft and thus rate of climb.

@aterpster. @RussR? I've seen this issue - a heading which might not intercept the radial - multiple times. What's the story? Why not a simpler, "climbing right turn to intercept" the radial rather than a specific heading which might not?

 

[Trogdor]

"Unwary" is a the problem. GPS absolutely helps because activating the missed will fix things, although the difference between the heading on the chart and what the GPS says to do can itself lead to confusion. I think one key is that, while many approach briefings tend to focus on numbers, the Plan View and the 10,000' picture it provides is incredibly important.

i also helps to have been caught by this at least once, preferably in a sim (that's what taught me about it). Or come across a thread like this.

Yes! This actually was a topic of discussion over at PilotEdge @coma24 since it is a key segment of the last I-rating flight they offer.

Also, and to your point, for the next guy, you’re welcome!

 

[luvflyin]

"Therefore, when an early missed approach is executed, pilots should, unless otherwise cleared by ATC, fly the

No, it is not pertinent because the VOR is not the MAP. The MAP is 1.7 miles before the VOR. The problem is that it is possible to fly to the MAP and then turn before the VOR. But if you turn before the VOR, you'll never intercept the radial.

View attachment 100862

Yeah. I get all that. Once again, I was replying to his "...my understanding is you don’t have to fly past the VOR but can turn laterally on a missed as soon as the vertical requirement on the missed has been met..." You do have to wait until the MAP to do that. Turns out he already knew that.

 

[Trogdor]

Yes. I should be explicitly stated that though as well to avoid any confusion.

The point here though is that you can be passed the missed and still meet vertical requirements before the turn to intercept.

 

[Trogdor]

"Unwary" is a the problem. GPS absolutely helps because activating the missed will fix things, although the difference between the heading on the chart and what the GPS says to do can itself lead to confusion. I think one key is that, while many approach briefings tend to focus on numbers, the Plan View and the 10,000' picture it provides is incredibly important.

i also helps to have been caught by this at least once, preferably in a sim (that's what taught me about it). Or come across a thread like this.

Unfortunately, it seems like a lot of GPS units screw up the missed as well in this scenario. I don’t have first hand knowledge but a few pilots who do say that units from both Garmin and Avidyne will get it wrong.

 

[midlifeflyer]

Unfortunately, it seems like a lot of GPS units screw up the missed as well in this scenario. I don’t have first hand knowledge but a few pilots who do say that units from both Garmin and Avidyne will get it wrong.

Interesting. In the missed approaches I've looked at with this feature, the GPS flight plan definitely displays the published heading. It has to because it is called for by the procedure. So the same issue exists when hand-flying. But when the AP is coupled, once reaching an appropriate intercept, at least in the three I've looked at, the turning stops.

 

[luvflyin]

Unfortunately, it seems like a lot of GPS units screw up the missed as well in this scenario. I don’t have first hand knowledge but a few pilots who do say that units from both Garmin and Avidyne will get it wrong.

I’m not so sure GPS gets it ‘wrong.’ My GPS unit experience is very limited though. Most is 430’s where it doesn’t even attempt to fly a Missed Procedure. It just puts the Missed Fix as next Fix, you push OBS to suspend sequencing and you fly the Procedure. I’ve done Simulator work with some newer ones though that do ‘fly’ the Procedure to some extent. They would solve the illogical result of flying the ‘heading exactly’ as stated in situations such as this, and get you on the Radial. Not attempt to fly this explicitly as if the Procedure said ‘…turn right heading 300 then intercept the the 269 radial…’

 

[luvflyin]

Interesting. In the missed approaches I've looked at with this feature, the GPS flight plan definitely displays the published heading. It has to because it is called for by the procedure. So the same issue exists when hand-flying. But when the AP is coupled, once reaching an appropriate intercept, at least in the three I've looked at, the turning stops.

G’mornin, looks like we was typin at the same time

 

[aterpster]

@aterpster can probably confirm (or deny) this, but I believe the missed is built around and a standard 200 ft/mile climb. This would require almost 2 1/2 miles from DA prior to the turn, putting the turn point slightly beyond the VOR.

Unless a climb gradient is specified it is basically a 40:1 (151.9 feet/nm) but with ILS there is a section 1, which provides for dip below DA then briefly climbs at a 28.5 to 1. Complex stuff. But, with a 15,000 runway here is a fair amount of assumed climb before the position of the VOR. Having said that, a climb to 3,500 probably goes south of the VOR. I see if I can find the TERPs maps.

 

[aterpster]

TERP maps are gone.

But, I flew in my G-5000 trainer and missed with a 1,500 fpm rate of climb at 140 KIAS. I reached 3,500 well prior to the VOR. The trainer started a turn at 3,500 but rolled out initially on a 226 heading to smoothly intercept the VCV 269 radial.

 

[Trogdor]

TERP maps are gone.

But, I flew in my G-5000 trainer and missed with a 1,500 fpm rate of climb at 140 KIAS. I reached 3,500 well prior to the VOR. The trainer started a turn at 3,500 but rolled out initially on a 226 heading to smoothly intercept the VCV 269 radial.

So in the end, the 300 degree heading is a “suggestion”? I assume the text is controlling and the “via” is really a suggestion here more than a mandate. The goal is to intercept the radial.

Follow-up question: Is there any place in the FAR/AIM that covers this kind of scenario?

 

[midlifeflyer]

TERP maps are gone.

But, I flew in my G-5000 trainer and missed with a 1,500 fpm rate of climb at 140 KIAS. I reached 3,500 well prior to the VOR. The trainer started a turn at 3,500 but rolled out initially on a 226 heading to smoothly intercept the VCV 269 radial.

They all do that, as will the situationally aware pilot hand-flying. The question remains, then why give a specific heading at all? Why not just, "climb to 3500, then climbing right turn to 6000 to intercept..."? Is there a TERPS or other procedure design reference for the rationale.

 

[midlifeflyer]

So in the end, the 300 degree heading is a “suggestion”?

I think in the end, the 300 degree heading is intended as a practical maximum.

Follow-up question: Is there any place in the FAR/AIM that covers this kind of scenario?

Not as far as I know. It's not even discussed in the IPH. A bit surprising since there are so many of these heading to intercept missed approaches.

 

[aterpster]

They all do that, as will the situationally aware pilot hand-flying. The question remains, then why give a specific heading at all? Why not just, "climb to 3500, then climbing right turn to 6000 to intercept..."? Is there a TERPS or other procedure design reference for the rationale.

Yes. Section 1 and Section 2 of ILS missed approach criteria. Descent below DA than 28.5 to 1 to end of Section 1 then 40:1 to top of climb. So, 3,500 isn't achieved in design until past the VOR, thus the heading of 300 to intercept the radial. Whether the procedure designer had the option to word it as you suggest, I defer to our resident designer.

In criteria, it is a combination straight-ahead and turning missed approach. And, as you know, because it is a ground-based navaid IAP, coding of the missed approach isn't a design consideration. Note how different the missed approach is for RNAV 17.

 

[luvflyin]

I think in the end, the 300 degree heading is intended as a practical maximum.

I'm not so sure about that. There was a thread a few months back. Situation was a climb straight ahead to an altitude then a heading/intercept a radial to a fix. The climb restriction was such that overflying the radial was certain for most airplanes. Because of obstructions on that side of the radial, the overflown side, 'shallowing' the intercept angle could be a problem. I'd say if you do go 'through' and need to get back to the radial it would be best to treat it as a practical minimum. Or maybe we aren't seeing maximum or minimum the same way. Anyway, if overflying and getting back, I wouldn't stop the turn short of 300 on this Approach.

 

[MauleSkinner]

I'm not so sure about that. There was a thread a few months back. Situation was a climb straight ahead to an altitude then a heading/intercept a radial to a fix. The climb restriction was such that overflying the radial was certain for most airplanes. Because of obstructions on that side of the radial, the overflown side, 'shallowing' the intercept angle could be a problem. I'd say if you do go 'through' and need to get back to the radial it would be best to treat it as a practical minimum. Or maybe we aren't seeing maximum or minimum the same way. Anyway, if overflying and getting back, I wouldn't stop the turn short of 300 on this Approach.

But would you turn to say, 320 or 350?

 

[Llewtrah381]

I see lots of valid conversations about getting to 3500 feet. But don’t forget you’re turning from 170ish to 300. In a standard rate turn, even if you rolled into it and out of it crisply, you’re talking about an additional 43 or so seconds until at the new heading, at least half of that time heading southish. First flying to 3500 and then starting that turn sure seems like you’d be doing so south of the VOR if you actually wait until the MAP to start things. Not sure if that figures into the reasoning.

 

[luvflyin]

But would you turn to say, 320 or 350?

What are the winds?

 

[midlifeflyer]

I'm not so sure about that. There was a thread a few months back. Situation was a climb straight ahead to an altitude then a heading/intercept a radial to a fix. The climb restriction was such that overflying the radial was certain for most airplanes. Because of obstructions on that side of the radial, the overflown side, 'shallowing' the intercept angle could be a problem. I'd say if you do go 'through' and need to get back to the radial it would be best to treat it as a practical minimum. Or maybe we aren't seeing maximum or minimum the same way. Anyway, if overflying and getting back, I wouldn't stop the turn short of 300 on this Approach.

If you do overfly the radial in the straight ahead climb, the heading is a solid intercept, so I wouldn't either. But that's not the situation we've been discussing. In what we have been discussing, blindly turning to the 300 heading might never intercept the radial and instead takes you further away from it. You are probably right about saying it's a maximum, but the current language can lead to this. In the examples I've seen, including this one, the RNAV box stops the turn when there is a 30 degree intercept to the radial.flying the published heading results in flying 30 degrees away from the radial.

fortunately, I came across this phenomenon in a sim (emulating a 172(.