IPC Interrupted

I finally finished up my iPC this evening. The winds were favouring runways 4, 7 and 10, which meant that the only RNAV approach that had a LNAV/VNAV option was RNAV (GPS) 04. That’s unfortunate, because runway 4 is the one favoured by the big jets – when the wind is coming the other direction, the approach with LNAV/VNAV is RNAV (GPS) 28, and runway 28 is used by commuter jets and turboprops, which means that my 120 knot approach isn’t too far off their approach speed. And sure enough, on the first attempt at an LNAV/VNAV approach they gave me a 90 degree turn onto the approach just outside the FAF. I did a passable but not great job. I followed the needles down well below the Decision Altitude (1200 feet).

The second time was even worse. Just as I was expecting another 90 degree turn half a mile from the FAF, I heard squelch break twice and an inaudible whisper, and then a “23Y how do you hear me”. That was followed by two vectors through the course that took me past the FAF, and an intercept vector that wouldn’t actually intercept. I “fudged’ the assigned vector to one that would intercept. Starting off having to start my descent before I’d gotten squared away on the approach path meant I never really got settled down. Even using the “TRK” reading on the GPS to try to get the right heading didn’t really make it easy. I kept it within acceptable limits down to the DA. But there’s no way in hell I would have accepted such a lousy set of vectors in IMC.

On both approaches, I’d been chasing the needles in both directions, and didn’t get stabilized, although at the end of it the runway was pretty much straight in front of me.

For the last approach, I asked for the ILS 04. This time, we were obviously getting vectored further away – I don’t know if the controllers know how to vector ILSes better, or if things were slowing down so they could have us on the approach longer. Although he tried to vector a Citation in in front of us, but when it didn’t work out he vectored them through the approach course and a 270 degree turn back onto the course behind us. On the downwind, Lenny reminded me to get my pre-landing checklist done, pick a speed and altitude, get well stabilized, and try to maintain both speed and altitude. I picked 110 knots and 2000 feet. And it worked – I got a better turn onto the approach course about a mile outside the FAF, I kept my speed and pulled back the throttle to get a 550 foot per minute descent at the speed I’d trimmed for. A quick check to make sure my TRK was 043 degrees, and then followed the needles down. Everything was pretty amazingly stabilized in both axes until about 1200 feet, when both needles started to wander. Personally I thought there was a bit of a windshift, but Lenny says he thinks I just got fixated on something after switching to the tower frequency.

Afterwards, we did a bit of ground review. Discussed some interesting things, like why on the RNAV (GPS) 04 approach, the DA for the LNAV/VNAV approach is the same as the MDA for the LNAV approach, but the required visibility on the LNAV/VNAV one is way higher (1.25 miles instead of 2400 feet)? (Answer: because you reach the LNAV/VNAV DA 1.9 miles from the runway end, but the LNAV MAP is right at the runway end.) Couldn’t figure out why the DA is so high, however. The ILS DA is 765 feet, compared to the LNAV/VNAV DA is 1200 feet. Discussed the other IFR trivia, looked at some stuff on the charts like the new T-airways (there’s one up near Ottawa on the L24/L25 chart).

Anyway, it’s nice to be current again.