OIC :wink2:
Localizer Approach, CDI & OBS
- Thread starter apr911
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OIC :wink2:
The question arose out of an approach in which my instructor made a comment that Im thinking wasn't really thought through. I had kept my CDI programmed on my last course and was waiting for it to "come alive" for the localizer before turning it to my inbound course (just in case I needed to switch the radio back to the VOR and resume tracking the Radial because of... any number of reasons) when the instructor told me to turn it to the inbound course. I told them I was waiting for it to start coming in at which point they stated it wouldnt provide proper guidance unless I turned it to course and turned it for me.
Obviously this is the case for a VOR but not a LOC yet at the time it challenged my understanding of what I thought I knew regarding a LOC based on previous experiencing using the LOC while VFR and from my ground school reading so I asked the instructor thinking maybe they hadn't thought it through fully when they said it but the instructor thought about it for a second before restating it.
Again, not a major issue, I figured I'd test both theories the next time we went up but my next flight was with a different instructor and when they stated something similar, well that's where the question came from.
All the initial responses said, functionally I was correct but the question was already beginning to morph into a "functionally you're correct but why wouldn't you want to set the OBS to match" and we started talking about LOC backcourses and HSI's where its possible to flip the orientation of the needle 180 degrees so that the back course works the same as the front course and other scenarios which I then compounded using a horrible set of wrong examples of how I've intentionally used an off heading on the HSI OBS for a course Im not tracking. Which, the examples being wrong poured gasoline on the fire regarding "why wouldn't you set it."
The question never was why do I need to set it but always was one of base functionality.
I feel like I am handling the workload just fine. In fact, my flights so far have been closer to PTS than to the much wider variance the course syllabus allows at this stage in my training. That being said, workload did play some factor in my challenge to the instructor as I didnt have a lot of time to go turning the OBS knob as a demo and the brunt of the challenge wasnt made until we were taxiing off the runway.
...with which I agree wholehartedly. The LOC needle will always center on the LOC course. The question is one of technique, which add human and other factors to questions of base functionality.
And, as I said, we are all different. I had an instrument student once who never needed any of the techniques for determining how to enter a hold. For whatever reason, his brain simply understood them completely after a single ground review. He didn't even need to write it down. I tried to put together a complex holding instruction involving DME distances on a VOR radial he was heading away from to test him. I screwed it up. My student's response, a second after I finished giving the instruction was, "That doesn't work." After spending 15-20 seconds thinking about it, yep, he was right.
OTOH, he's also the same student I mentioned earlier - who did not like to tune spin the OBS to the LOC course and often forgot to do so with a VFO as well.
Go figure.
My typing is getting better, eh?VFOs are pretty rare these days, now that everything is digital.
I'm like the student you described in many ways. I didnt intrinsically understand holds after 1 ground lesson but it was more about the hold itself than the entry to it. Once I got hold visualization down it clicked in my head and I was able to work out the entry without drawing it out.
Im the same way with VOR intercepts. I have sufficient situational awareness to maintain in my head a general position, especially in reference to a fixed point such as a VOR so I usually dont have to find my current radial to determine my intercept course for an assigned radial and I set my OBS directly to the assigned radial even though I dont know my exact current location. Even if you gave me a surprise VOR that I was unfamiliar with, I wouldnt much care my exact position as I just need my relative position (i.e. left/right of assigned radial and to/from side of the VOR) to compute an intercept. Drives my CFII nuts but like you they tried to trip me up with a complex question that they themselves had calculated wrong and when I started flying my intercept we argued for a moment, both recomputed, agreed it was right and they stopped making such a big issue of it.
About the only time I'm "off" in my computation is in the same area where the CDI starts getting difficult to track... Somewhere inside of 5NM from the station.
I do try to remember to find my current radial as often as possible because I know when I go for the check ride its something the DPE is going to want to see but I dont strictly "need" it. That being said, back in college I tested in the 98th percentile for complex mental math and relational data processing. I guess my brain is just wired for it.
I memorize credit card numbers complete with expiration and CVV code after typing them in 3 or 4 times. I dont try to memorize it but it sticks in my brain and I cant get rid of it... I still have CC numbers in my head that have long since expired. A lot of the mnemonics and other acronyms I HAVE to write on the board for a DPE otherwise, I'd just rattle off the list of things and most DPE's wont accept that as they want to see some form of memory aid, convinced as they are that you cant possibly know/remember all of them. Going through my private, I actually had a harder time memorizing all the mnemonics than I did memorizing the meanings.