Recommendations for OBS during LOC approach?

[NM Doug]

Here's the long story background: I was flying in to KSAN tonight from KAVX (with a very patient controller who must have wondered why he agreed to take on this I-8 rating flight being flown in a 172 ), and I was receiving vectors to the final approach course for the LOC RWY 27 approach. I had tuned in PGY on NAV2 two hours earlier (OK, I exaggerate), but I didn't know ahead of time where along the final approach path I would be vectored to join it.

I had the NAV2 OBS set to 314, which identifies CIJHI, because I was at 2600, and the "at or above" altitude for CIJHI is 2400.

But then, as the controller gave me the clearance to approach, I glanced down at my plate to see which fix he had mentioned (error #1 - if I start counting now, anyway - because I jumbled all the instructions in my head and had to ask, "say again" ). This time, he gave me a (re)intercept heading of 290 and an altitude of 2000 until established, and he sent me over to the tower.

When I called the tower, I reported inbound "just outside" REEBO, but now in retrospect, I'm not sure if I was inside or outside REEBO. I twirled the OBS on NAV2 to 304, which identifies the REEBO fix, but...well, I misread the VOR needle. I thought I was outside of REEBO when in fact, by this time, I was definitely inside, and then I added to the error by climbing back up to 1800, the "at or above" altitude before reaching REEBO.

Then I caught the error reading the VOR needle, figured out I was inside REEBO, put in flaps, and made the steep-ish approach for landing that I had intended to avoid.

So my question is this: when being vectored for a LOC approach, or another approach where various fixes during the descent are radials of a VOR somewhere off to the side, which fix does it make the most sense to have dialed in to the OBS on NAV2? The final approach fix (REEBO, in this case)? I think I would have simplified my situation in this case to have had the FAF dialed in, instead of one of the more distant fixes. I suppose if I were vectored on to the approach path further out, I'd have more time to establish my position with knob twisting.

- Doug

[Steve Caffey]

Alternate method: do you have DME? Each fix on the LOC 27 approach can be identified by DME. Example: REEBO is 6.5 DME, CIJHI is 8.4, OKAIN is 12.3 (DME from I-UBR, the localizer)

If you don't have DME, then it is much harder. I believe you'd then have to set the OBS number 2 to whatever fix is next to ensure you're at or above the altitude for that fix.

[Brandon Grchan]

To answer Steve's question Doug usually flies /U

this question is above my pay grade pilot wise but It never hurts to ask were you can expect to intercept especially if your /U the controller will understand

[NM Doug]

Thanks, Brandon and Steve - I'll try both suggestions out in the coming days. One approach available at Carlsbad (a focus airport for tonight) is a LOC/DME, so I'll have to be /A - it will be good DME practice.

I'll experiment some with the NAV2 OBS workflow on that KSAN LOC approach while /U when able, too.

- Doug

[Keith Smith]

Doug,

Excellent question. If it feels like this is a lot of work...it's because it is There is very little room for misinterpretation of the information that is delivered through the deflection of the needles. Don't be afraid to verbalize what you're setting on the OBS, which fix that represents, and the double check whether you are inside of outside of the fix.

Three things jump out that could make your life easier:
1) while you're being vectored on the downwind, don't be shy about tracking your location relative to those stepdown fixes to the extent possible

2) ask ATC for some help if you're at all unclear. Either while you're being vectored (that would be ideal), or after receiving the approach clearance, ask the controller which fix you'll be closest to when you join the localizer. That will help you set up your NAV2 so you don't have to guess which stepdown to configure for.

If in doubt, I would start from the furthest fix and work through the step downs one at a time (but quickly). Once you see the needle transition from the right side to the left, that new fix that you dialed in is the one that you'll be crossing next. That will tell you what altitude you can descend to prior to reaching that fix (once established on the localizer. Prior to becoming established, of course, you maintain the last altitude assigned by ATC).

If you haven't seen it already, there is a reference article on the PilotEdge Training Center which references how to fly that approach /U, it's part of the I-8 rating support material.

Good luck!

[NM Doug]

Thanks, Keith -

I like the verbalizing technique. Even when things are accelerating and tasks are crowding together toward an overload situation, I imagine it can be a useful tool for slowing down a racing mind. Taking even just a few seconds to be able to think clearly sounds like a great skill to practice.

Last night, I tried out asking ATC for where I could expect to intercept, as you and Brandon suggested, and I could almost feel my blood pressure go down - it worked very well.

The other thing that dawned on me last night was that I could more or less expect my next instruction to be the multipart approach clearance (3 miles from.... turn heading.... remain at or above..... cleared .....) when my current direction was perpendicular to the approach course. The instruction has to put me within a shallow intercept of the approach course (unless it's a pathological situation), so if the approach course is 270 and I'm currently on 180, it's reasonable to get the clearance with the heading instruction of 240 or 250. The perpendicular course closes the distance between me and the approach course at the quickest rate, and a 60 or 70 degree turn to intercept course is pretty reasonable. I wonder if this is the most common way the vectoring turns out.

Looking back at my thought process before, I think I may have been unconsciously expecting one more vector in there (e.g. 225 in the example above) before the clearance, so I was caught off guard and had trouble when the multipart clearance came. Funny, how expectations get in there and mess up hearing/comprehending!

- Doug

[Jason Baxter]

I was the controller on duty the evening in question, the guys have pretty much covered the pilot technique side of the approach. However, just to settle the score you were in fact directly over REEBO when you called 'inside' which is why I snickered a bit thinking "not by much". A pleasure working with you, aside from missing the PTAC you did well.

[NM Doug]

Thanks, Jason - consider the score settled...until the next "improvisation," that is. Last time I was flying r/w, it was a beautiful Sunday, and I returned to my home airport to find the pattern hopping and an instrument student flying practice approaches on the ILS. I'm not sure exactly what he did, but I think the student flew a low approach when the tower was expecting a full stop. The controller came on and said, "XXXX, I speak for all controllers when I say, we don't like surprises."

I really appreciate the PE controllers' professionalism, patience, and yes, humor.

- Doug