IFR 19: NDB Approach
Yes, I’ve got an over-full work schedule, but what better way to decompress and get my mind off work than by practicing a full NDB approach in gusty crosswinds! Fun stuff huh?
After over two weeks of not flying due to delays from scheduling and weather problems instructor R and I took off into winds of 15 kts gusting to 21 this morning. But first, we talked and planned our flight.
The talking covered several things, one key thing was if we should fly or not. After discussing the effects on enroute flight, takeoff, and landing, and recognizing that we didn’t have to land at our destination, we decided to fly. Enroute, the winds just cause turbulence. Since we’re both familiar with flying in bouncy air and don’t have potentially quesey passengers, this wasn’t an issue. Actually, it was a benefit since it got me practice flying IFR in bumps.
The cold front had passed, and the weather was trending smoother. But that trend was slow and wouldn’t happen soon enough to affect our flight. So, takeoff and landing was the key issue. Our home airport was reasonably well aligned with the winds for a 5-7 kt crosswind component on departure.
I once memorized the table of sines for each ten degree increment. (The trigonometric sine of the wind angle to the runway times the wind speed is the speed of the cross wind component. The cosine gives the headwind/tailwind component.) But I don’t use that now. Instead a rough approximation is close enough: 1/3, 1/2, 3/4, or full for the angles 20, 30, 45, or 60 degrees and over.
The plan for today is the NDB approach at KCJR (Culpepper). R was playing Potomac Approach giving me my headings and altitudes as the controller would do. He took me around the class bravo and eventually gave me direct Casanova VOR the to the approach. CSN VOR was a transition to the approach and the missed approach holding fix as well. The NDB approach to Culpepper does not have the NDB on field, instead it is 4.4 miles before the field. So, the approach would go from CSN to MSQ (the NDB), then outbound for the procedure turn, then back inbound to the NDB again. I would pass the NDB for a second time, then continue outbound from the NDB to the airport.
I expect this will keep me occupied.
During the first approach I was behind most of the time. The ADF needle points directly to the NDB station, if I’m flying with a 20 degree adjustment to my course for a crosswind correction, I need to “adjust” the reading of the NDB in my mind correspondingly. My actual heading is my magnetic course plus or minus my crosswind correction. Outbound from to the airport I will need a right crosswind correction, inbound I’ll need a left correction. Determining the correct NDB reading is taking up way too much of my brain cells. So, I was behind. Two weeks off didn’t help.
I had brain freeze on my minimum altitude and my heading corrections. R talked me through it. One good thing: At least I remembered to start my timer crossing the NDB for the second time on our way to the airport. That time is the only way to find the missed approach point for this approach.
Finally, at the missed approach time and the right altitude (thanks to R), I looked up and took the foggles off. Wonder of wonders, the runway was more or less where it should be. I’d previously got the winds as 350 at 8 kts gusting to 18, with this runway heading that 8 gusting to 18 was the full crosswind component. I made the landing, using the crosswind skills I picked up at the crosswind simulator last year.
After landing on the centerline and coasting to taxi speed on the runway (R saying, “stay off the breaks, no need to use tire rubber if you don’t have to”), I pulled off. R praised my crosswind landing and he taxied back for takeoff and praised my crosswind landing as we talked out the approach.
R tells me, “It’s easier to use 30 degrees or 45 degrees correction on the NBD, you need to keep it simpler for yourself. Don’t make work. But inside the final approach fix, you can’t use that much. Keep it smooth, and even. Make small changes, watch your trend.” I wanted to go back and do this approach again, I wanted to get it right.
So, why am I spending effort learning NDBs? After all they’re being decommissioned, there are only two in my area that are still working now. Because first, my plane has an ADF, so I need to know how to use it. Second, if I can fly an NDB approach successfully then I’ve got enough spare brain cells to handle everything else. Third, I want to. It’s fun, in a weird masochistic way. (Yes, I accept that my idea of fun is, uh, different.)
So, we took off, climbed to 2500 and intercepted the NBD outbound again. It went better this time, I was if not ahead of the plane, then roughly abeam it at least. The ADF needle was off a little near breakout, but not very far off. And it had been a bit off the first time too.
But this time when I took off the foggles, the runway wasn’t in front of me, it was about 40 degress to the left. “Jesus!” was my comment.
R said, “I’m glad this happened. First, it tells me you’re not cheating (looking below the foggles). Second NDB approaches aren’t very accurate. This teaches you that you have to look all around when you break out on an NDB approach.”
“So that’s why the minimums are so high for an NBD approach, I’d have to circle to land now.” I said.
R asked, “What are the circling minimums?” I looked, they were the same as the NDB minimums.
We headed back home. R continued to play Potomac approach for me, and he found some covers for the instruments. I promptly “lost” my heading indicator and reverted to my compass in rough air. Ok, I remember how to do this, but for some reason I can’t seem to remember that a standard-rate turn is 3 degrees/second, or 3 seconds for ten degrees. So, when he asks how long do I turn, I made sounds, but no useful speech comes out. R ignores that and tells me. Duh, I remember now.
I keep thinking UNOS: Undershoot North, Overshoot South for the compass turning errors. And getting mixed up as the compass is numbered backward (we see the backside of the aviation compass, so the numbers go the “wrong” way). I should have this down by now! Something else to practice on my X-Plane simulator software.
R takes me up toward home. I’m thinking he’s gradually turning me to the airport, but he’s not. At some point he puts a scenario forth: Something’s gone wrong and I need to find the nearest airport and land there. So, I push the “nearest” button on the GPS, and it gives me a 138 degree heading. This can’t be right. I’m on a heading 060 degrees to home! This GPS heading sends me away from home, something’s wrong.
After dithering, and some prodding from R, I turn to the now 140 degree heading and he has me take off my foggles after a bit. The airport’s ahead. The “something wrong” was not the GPS of course, it was my idea of where we were. I’d lost my situation awareness in all the compass heading stuff.
So, a good lesson. I got some rust off, became more confident on using NBDs, albeit not highly proficient. And I got a very good lesson on trusting my instruments - including my GPS. And, my landing at home was in a 6 kt to 12 kt crosswind. I still have my crosswind chops.
Next up: proficiency check flight with a VOR, ILS, and GPS approach. Then, on to cross-country flights.