OSH approach question

Dave Siciliano

Dave Siciliano

Final Approach
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Dave Siciliano
Last trip up to OSH, they were working on a bunch of stuff on the airfield and the only approach available to a usable runway was the VOR or GPS RWY 18. But, the VOR was down; so, the GPS 18 was it. Ceilings were about 800 feet (I have a DME, but the VOR was inop. So, let me tell you what happened and ask what my options were <g> (I also am slant G)

I was about 5 miles to the west of the airport being vectored due North by Chicago Approach (on top of a layer). Couple folks were able to get in from the east over the lake visually, but it was close. Based on the ATIS, ceilings were below minimums. As I was just about abeam the VOR, Approach asked what I wanted to do and I requested the GPS 18. Approach then said words to the effect of: I suppose I need to bring you over the VOR for that. I responded vectors to final could also work. Approach took me about three or four miles farther north, gave me a right 90 degree (with winds of over 30 knots almost due west). As I neared the extended approach course to the IAF, Approach told me to turn right 90 degrees, intercept the final approach coarse, cleared for the GPS RWY 18 Approach. Shortly after that, they asked if I had intercepted the final approach coarse; I answered affirmative and they turned me over to tower.

So, any thoughts about how this was conducted; or what the options were?

Best,

Dave
 

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well there is that whole question of how do you decide when to start your descent. theres probably a fair amount in the AIM or FARs that will tell you if it was technically legal to accept the approach clearance. but i think that from a practical standpoint, as long as you were within 10 miles when you started the initial descent (as if you wouldve done the PT) then there was nothing to be concerned about
 
Vectors to final is not a legal option unless the controller has the final approach course including the approach gate (which is based on the final approach fix) on his scope. Since this approach is one of those out-and-back types which does not have a FAF, it is not possible to get legal vectors to final. The controller should have sent you back to the VOR to do the full approach with PT, which was what he tried to do. Otherwise, nobody knows quite where you are with respect to the final approach course and where to start down.

Yes, in your case, with the GPS, you know when you're close enough to the VOR to start down (provided you have a good enough understanding of TERPS to know where the limits of the protected airspace are), but generally speaking, a pilot can't know when it's safe to leave the last assigned altitude unless the pilot starts out over the VOR, goes out and completes the PT within 10nm, and intercepts the final approach course from the PT side.

All in all, it worked out OK for you that day, but if it hadn't, the FAA Flight Standards folks would have been very critical of both you and the controller.

BTW, I discussed this in detail with the folks at AFS-410 after a controller tried to give me vectors to final on a similar approach and cleared me for it with an 18nm turn-on -- and told me I could descend to MDA from that point. I knew that wouldn't work (there were big towers about 15nm out), and stayed up at last assigned until I knew I was inside the protected area, but that would not have been possible with only a VOR (which is all you need for one of these approaches). I called AFS-410 the next business day, and they concurred -- and gave the TRACON's overseeing ATC office at Region a call about the situation.
 
I guess I was comfortable with what occurred because of the GPS. Of course the VOR was OTS; so, I didn't see any benefit to overflying it. Step down point is on the GPS.

Second question, with just the GPS, was I able to descend to the DME minimums, even with the VOR OTS?

Best,

Dave
 
Overflying the OTS VOR was the correct thing to do. In the GPS approach the VOR should be a way point so it would not matter if it was not working. As Ron said ATC should not have down a vector to final on that one unless they could scope out the approach course. That being said I have gotten those types of vectors form lots of ATC places. You are pretty much ok on that approach and not dodging mountains or big towers as long as you stay above 1420MSL out side of Woman and inside 10NM of the VOR.
 
In reality, ATC can plot the final approach course if they don't already have it on their scope. I don't know if they can also plot the approach gate (I doubt it), but that's a detail that's often overlooked.

I've seen a controller plot the final approach course using the heading from the approach plate and then issue vectors to final in person. Don't know if that's perfectly legal, but I don't see anything unsafe about it. I've gotten vectors to final for that same approach in IMC before...

-Felix
 
sba55 said:
In reality, ATC can plot the final approach course if they don't already have it on their scope. I don't know if they can also plot the approach gate (I doubt it), but that's a detail that's often overlooked.

I've seen a controller plot the final approach course using the heading from the approach plate and then issue vectors to final in person. Don't know if that's perfectly legal, but I don't see anything unsafe about it. I've gotten vectors to final for that same approach in IMC before...
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Felix is correct -- it's possible to do, but not authorized by the ATC Handbook. A controller around here tried that on me one time when Potomac Approach was busy and Pax River Approach tried to do them a favor by vectoring me to final on the ILS 4 at Easton (that's normally Potomac's airspace and the ESN ILS final approach course does not appear on Pax River's scopes). Unfortunately, their calculation of the final approach course was such that when they said "Turn right heading 010" to intercept the final approach course, we'd already flown through it on our northwesterly heading. Not cool. And not safe, either.
 
Ron Levy said:
Felix is correct -- it's possible to do, but not authorized by the ATC Handbook. A controller around here tried that on me one time when Potomac Approach was busy and Pax River Approach tried to do them a favor by vectoring me to final on the ILS 4 at Easton (that's normally Potomac's airspace and the ESN ILS final approach course does not appear on Pax River's scopes). Unfortunately, their calculation of the final approach course was such that when they said "Turn right heading 010" to intercept the final approach course, we'd already flown through it on our northwesterly heading. Not cool. And not safe, either.
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No argument there :)
 
Thanks for the input. Of course, I wouldn't have taken it if I wasn't comfortable being able to fly it safely, but didn't think it was proper. Thanks for confirming. I was in the 10 mile ring, didn't descend below that sector altitude before the step down point and broke out about 800 AGL. Nice long runway; knew the area well and with the GPS and terrain awareness feature, had excellent terrain awareness. Guess next time they ask, I should just keep my suggestions to myself <g>

BTW, I erred in describing this; it was Chicago Center, not approach. Madison Approach had turned me over to Chicago Center.

Of course, on a normal RNAV, one can be vectored to the IF if more than five miles out and the turn inbound is 90 degrees or less; so, I didn't feel this was a lot different; although, there was no IF <g>. On the Garmin, I painted an extended approach centerline using the direct feature and putting in the runway heading. That was a great help in intercepting what was the final approach course.

I appreciate all the comments.

Best,

Dave
 
Here's what Bill Butler over on the AvSig Board had to say (he is a controller).

Best,

Dave
======================================================
Actually, it is quite clear where he was supposed to be vectored to:

1. Assuming the weather was crappy (official NWS term), he was supposed to be vectored so as to be established on the final approach course two miles outside the "approach gate", which in this particluar case was five miles (total=7miles) from the approach end of the runway. (ATP Handbok, 5-9-1) Sounds as though that didn't happen.

2. They were also required to intercept the final at an angle no greater than 30 degrees (20 in some cases)--sounds unlikely.

3. And they were specifically barred from doing it at all if they didn't have the final approach course depicted on the radar display, which doesn't sound likely either.

Aside from 1,2, and 3 above, it was a cleanly executed operation.

My advice to the uhh...victim would be to say, "thanks anyway, we'd like to decline any further federal assistance and proceed to the IAF."
 
I don't get why out and backs are required for GPS approaches, even if overlayed. I have an MSA on the plate, and my GPS tells me whether I'm in the MSA or not, as long as I am anywhere on the FAC, I know where I am on the FAC with a GPS, I don't really grasp the problem here. For this approach I'm good anywhere at 2600 when within 25 of the airport, and if I am anywhere on the FAC I'm good down to 1420 inside of 10 miles, and lower inside of 2.9DME. With a VOR only, I can see the issue. With GPS, I think a lot of the PT stuff is archaic - especially in the flatlands.
 
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EdFred said:
I don't get why out and backs are required for GPS approaches, even if overlayed. I have an MSA on the plate, and my GPS tells me whether I'm in the MSA or not, as long as I am anywhere on the FAC, I know where I am on the FAC with a GPS, I don't really grasp the problem here. For this approach I'm good anywhere at 2600 when within 25 of the airport, and if I am anywhere on the FAC I'm good down to 1420 inside of 10 miles, and lower inside of 2.9DME. With a VOR only, I can see the issue. With GPS, I think a lot of the PT stuff is archaic - especially in the flatlands.
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The MSA does not make you "good anywhere...within 25 of the airport." All it does is given you obstruction clearance, and there's a lot more to an approach than that -- protected airspace, gradients, etc. Yes, some day, free flight may come to pass, and the TAA's are a first step in that direction, but for now, on overlays, we're tied to the originally surveyed flight path.
 
Ron Levy said:
The MSA does not make you "good anywhere...within 25 of the airport." All it does is given you obstruction clearance, and there's a lot more to an approach than that -- protected airspace, gradients, etc. Yes, some day, free flight may come to pass, and the TAA's are a first step in that direction, but for now, on overlays, we're tied to the originally surveyed flight path.
Click to expand...

Yeah, I know, but I know at 2600, I'm not going to smack into anything within 25 miles of OSH, and with a moving map approach certified GPS, the PT is really quite unnecessary for a cat A approach. If I'm on the 002 (from memory) radial and w/in 10 miles, I can get down to 1420 with no issues. I never understood the necessity for the PT if I am coming in from the north on this. I'm probably going to be cleared down to 2600, or even if not 2600, 3000 or 3500. Now, I'm guaranteed that w/in 10 miles I will not smack into anything down to 1420 feet if I'm on the 002. If I can't lose 1500 feet in 10 miles in, well, any plane, something is wrong. LIke I said, I totally understand the need for the full approach while /U because you do not know where you are at until you cross the station. But with a 129 or 146 GPS, it's ridonkulous when coming from the north on this to have to fly to the VOR, to fly back to where you just were, to fly back the VOR again.

If you're going to slap an overlay on it, it wouldn't be that hard to say "No PT if /G and arriving from 317 CW 047"
 
EdFred said:
Yeah, I know, but I know at 2600, I'm not going to smack into anything within 25 miles of OSH, and with a moving map approach certified GPS, the PT is really quite unnecessary for a cat A approach. If I'm on the 002 (from memory) radial and w/in 10 miles, I can get down to 1420 with no issues. I never understood the necessity for the PT if I am coming in from the north on this. I'm probably going to be cleared down to 2600, or even if not 2600, 3000 or 3500. Now, I'm guaranteed that w/in 10 miles I will not smack into anything down to 1420 feet if I'm on the 002. If I can't lose 1500 feet in 10 miles in, well, any plane, something is wrong. LIke I said, I totally understand the need for the full approach while /U because you do not know where you are at until you cross the station. But with a 129 or 146 GPS, it's ridonkulous when coming from the north on this to have to fly to the VOR, to fly back to where you just were, to fly back the VOR again.

If you're going to slap an overlay on it, it wouldn't be that hard to say "No PT if /G and arriving from 317 CW 047"
Click to expand...
Ed, what you're asking for is a total rewrite of TERPS. It ain't gonna happen in advance of Free Flight.
 
Ron Levy said:
Ed, what you're asking for is a total rewrite of TERPS. It ain't gonna happen in advance of Free Flight.
Click to expand...

Actually, all I am asking for is the FAA to use some common sense. Oh wait, nevermind.
 
bbchien said:
Ed, remember this is about insurablility. Not about possibility. Hard to remember that.
Click to expand...

I know, but if I am /G and already at 2600 inbound from the north, what exactly does the PT do for me - or anyone /G? Nada.
 
And eventually good controllers will figure out how to vector to final on a GPS approach. This skill is generally still lacking.
 
bbchien said:
And eventually good controllers will figure out how to vector to final on a GPS approach. This skill is generally still lacking.
Click to expand...
Controllers are not permitted to give vectors to final unless they have the final approach course with final approach gate depicted on their scope. That, not skill, is the long pole in the "VTF to GPS" approach tent.
 
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