(I started this post Tuesday evening and have been busy working, flying and mothering so it hasn't been finished until now! Perhaps tomorrow I'll get to the afternoon flight...)
We got started bright and early today but again had no actual IFR to play in. The missions for the day went ahead as planned anyway. I filed KSQL OSI SAPID SANTY for the LOC RWY 2 approach into KWVI (Watsonville).
Upon startup, the display for COM1 was blank except for a flickering vertical line separating the com from nav frequencies. Hello, N24AF, anyone? :) Brightness controls altered the glow around the knobs but didn't change the critical display. Combined with yesterday's flakiness on the #1 CDI (fed by NAV1), we were suspicious but had other troubleshooting ideas as well. Jason thought it was potentially a sunlight-on-sensors issue (it's auto-dimming), and the sun was lighting us up from the back in the parking area. By the time we taxied most of the way to the run-up area (into the sun), the display was behaving properly. There was still some wariness about the CDI, but we were willing to give it another chance today to see how it went. (Spoiler: it was not as flaky, but never agreed with #2 CDI, which was still solid. Was within the 4-degree tolerance, but, you know, you'd like to have complete confidence in the instrument.)
CIGARS. Lights, camera, action. Pre-takeoff briefing (verify runway, last check of wind, takeoff abort conditions, emergency procedures before and after rotation). We talked on each flight about how we should be starting a timer when cleared to depart and checking in after that 5 minutes if the expected higher altitude hasn't been cleared. In the bay area, in particular, there are plenty of nearby MEAs above 5000', so in actual IMC it would be pretty important to follow up with ATC. We forgot on every flight to set a timer, and Jason related how even when he starts a timer, there's enough going on as the flight starts that it's usually way later when he notices how far past 5 minutes the timer has gone. Countdown timers with audible or haptic alerts would be best for reminders like this. Had I not forgotten my Apple watch charger, the watch-based ForeFlight timers may have been able to fulfill this role. I think I'll try to incorporate starting the timer as part of the pre-takeoff briefing as we roll onto the runway, so at least step 1 has a deterministic trigger point.
Clearance:
We followed the departure clearance and were soon vectored southeast then cut loose to resume own navigation. I was quite busy aviating and navigating and didn't get ahead of the plane by the time we were at Woodside VOR ~6nm away, so I wasn't ready with my 5Ts. My living autopilot took over in the right seat while I went into executive mode, assessing and directing the current phase and planning the next phase (verify SAPID with GPS waypoint and SJC radial). Here's an example of what the 5Ts look like for SAPID from OSI:
Turn: none
Time: none
Twist: none (already twisted #2 CDI for SJC R-210, verify)
Throttle: none
Talk: none
With that 30 seconds of planning, I had caught up with the plane and was now six minutes ahead! That was really pretty sweet. I had lots of opportunities to do configuration change flow/checks (mag/DG sync, flight instruments, engine instruments, breakers/switches, throttle/mixture, fuel controls; checklist). By getting ahead, more time is available for the management of the current phase of flight and being prepared. An autopilot is a magnificent tool for facilitating this.
Next was SANTY (6+ minutes ahead once we passed SAPID). SANTY is an IAF for the LOC RWY 2 into KWVI, so the workload would start increasing there. Here's what SANTY's 5Ts look like; you can see that there's more to work on:
Turn: left to track the SNS R-293
Time: none
Twist: #2 CDI for identifying SNS R-293; #1 CDI for the I-AYN localizer; these courses intersect at NALLS, the IF for turning outbound for the procedure turn and also the FAF inbound.
Throttle: none
Talk: none
Before getting to SANTY it was also time to start the 5As:
ATIS: tuned and received.
Altimeter: Make note of it from ATIS, but don't enter into the altimeter until cleared for the approach.
Approach briefing: this is the attention-consuming part. Pull up the plate (or paper), check that it's the right approach at the right airport. Read everything on the top, out loud is best. If it's appropriate to load any frequencies at this time, go ahead and do so (see the 5Ts above). Read restrictions. Memorize the first part of the missed approach (climbing right turn to 5000). Orient on the plan view, visualize how you'll fly it and how the instruments will guide you. Check the profile view for altitude changes and where. Get the BOTTOM LINE: How low? How far? What's next? 700', at the MDA or 4:12 from NALLS, climbing right turn to 5000'. That last bit is the missed approach trigger. If you get down to the minimum descent altitude of 700' or go 4:12 (at 90 kts for the 172) past the FAF and can't see the runway or aren't oriented to use normal maneuvers to land, execute the missed approach by making a climbing right turn to 5000' (after which time you'll head southeast to the SNS VOR for a hold, but first is just to get up and clear of the mountainside). The FAA has cleared the area and guarantees obstacle and terrain clearance if you follow the instructions, so plan to do it.
Avionics: This all ties together, right? Redundancy built in, lots of chances to double-check yourself and catch any tuning errors. Gather the avionics items from the approach plate, either tune it now or note it for the 5Ts for the upcoming trigger.
Airplane: Flow/checks. Descent checklists. DG sync. GUMPS.
With the LOC RWY 2 approach, you turn outbound at NALLS and perform a procedure turn within ten miles of NALLS. 90 kts is 1.5 nm per minute, so flying outbound for two minutes, a 45-degree right turn for one minute, and a left standard-rate turn is well within the 10 nm requirement. This was done, and then it was a matter of tracking the localizer inbound, maintaining airspeed, and reducing altitude at the appropriate times. 2200' at NALLS, the FAF, 6.3 nm from the runway threshold, down to 700'.
I forgot to start a timer. In practical terms, the GPS was also telling me where the runway threshold was, but it's sloppy to not utilize the correct methods for a non-precision approach. And here's why the timer is important: Imagine you're in actual IMC and pass NALLS. You can safely descend to the MDA of 700'. At some point, however, 700' is no longer safe and you need to execute a missed approach if you can't see the airport environment. You can only identify that point by some kind of nav (GPS fix, a cross-radial from a VOR, etc) or by time since the FAF. Being forward-acting pilots, our 5Ts and 5As have ensured that we're situated to identify that point, but what if.... What if the GPS RAIM check fails? What if the VOR turns out to be unusable below 1000'? There are enough reasons to have that timer going.
We executed the missed approach just before the airport and noted that they were using 20 for landing this calm day. Climbing right turn to 5000' and heading to SNS VOR. Once established in the climb (with flow/checks complete), a quick consult of the plate filled in the details for the rest of the missed approach procedure. Sometime in there we had also switched to CTAF for WVI, so needed to communicate with NorCal approach again for holding instructions at SNS. We would be using the published hold, so the controller just told us when to expect further clearance, the current time, and to advise if we wanted to leave the hold earlier (since we were on a training flight in VMC).
I looked at the plate for inbound holding course, mentally mapped it on the DG, and made my best guess for how we'd enter the pattern -- direct, parallel, or teardrop. Then I used the thumb tool as a redundant check and found that my guess was wrong! (Psst, the system works.) It was obvious that the 5Ts would be happening frequently and in quick succession in the hold, so I started working it out. The goal is to have the inbound leg be 1 minute long, so depending on winds, the outbound leg and turns may be longer/shorter and abnormally shaped. Note to self: review the airspace extents; my recollection is 4 nm on the inbound (non-holding?) side, 8 nm on the outbound (holding?) side.
The first outbound leg was one minute, and the resulting inbound leg was well over 2 minutes! The T for time would need adjusting on the next outbound leg. Just when does that outbound leg start, anyway? The holding fix is at the end of the inbound leg, then there's a standard rate turn, at the end of which you should be on the reciprocal course. The outbound timer starts when you are abeam the fix; in this case, when the CDI flipped from "to" to "from."
The third outbound leg was more like 15 seconds, and resulted in an inbound leg of close to one minute. I started getting through the approach briefing, and by the time we were on the fourth circuit and the controller asked if we wanted to wait, I was prepared to ask for a clearance to the RNAV (GPS) RWY 2 approach back into KWVI. This is what that set of holds looked like, though it felt like we were doing some kind of spirograph design. The pattern was getting tighter as I shortened the outbound leg to standardize the inbound leg.
We exited the hold on a heading of 260, IIRC, being vectored to the IAF waypoint RISPE. While enroute, more flow/checks and 5Ts to get ready for the approach. As we headed out over the Pacific Ocean, it was clear that we would be north of RISPE and got a DTK from the GPS to take us there. The controller noticed the change and asked us what we were doing. My memory here is fuzzy, but I believe we had been cleared for the approach. If not, surely at least Jason and I would have had a conversation about remaining on the vector even if it was off-course v. pinging the controller. He did not object, however, when we told him we were correcting course to go to RISPE. Perhaps because he knew we were training and had already proven to be a nice controller :)
These approaches are pretty simple. They'd be even simpler if this aircraft had a WAAS-enabled GPS, which would provide vertical guidance as well as horizontal and allow use of a glidepath down to lower (LPV) minimums. Without WAAS, however, we'd be managing our own altitude in accordance with the LNAV row. NBD (LOL, unnecessary acronym -- no big deal), we'd fly it just like the localizer, but recognize waypoints and distances with the GPS instead.
The LPV DA is 458'. This means that as you're descending on the glidepath, when that path intersects an altitude of 458', that's the MAP. At that point, you're 288' above the touch down zone elevation (TDZE). This DA happens short of the runway, allowing time to see the airport environment and runway lighting and use normal visual maneuvers to complete the descent.
The LOC MDA is 700' and the LNAV MDA is 740'. But where? It seems reasonable that the LOC MDA is closer to the runway threshold since it's lower, but..... The only things I know for sure are that (1) the LOC approach specifies 4:12 after crossing NALLS as a (somewhat) definitive marker for when to execute the missed; we'll forego the imprecision for now; and (2) the LNAV has no time, but the rule is that the MAP is the last named waypoint; in this case, RW02, the threshold of runway 02. At RW02, however, you still have 588' to descend! Note this MAP explanation for future reference.
The other little complication to this approach was that Jason wasn't confident the non-WAAS GPS would properly manage the linear scaling. When using the LNAV portion, the linear scaling can be 5 miles when enroute (beyond 30 nm), 1 mile in the terminal area (30 nm to the FAF), and 0.3 miles on approach (from FAF to runway). This is to increase the course deviation sensitivity, ensuring your best chance at alignment with the runway in the clouds as you approach the airport. Ideally, the GPS is smart enough to do it for you when you cross 30nm and the FAF, but Jason didn't trust it so he manually switched it. People fail checkrides for that little detail, and it is an important detail.
As we neared the runway, we opted to convert to more of a circling approach since 20 was in use and it was almost lunchtime. On final for 02, we turned right to offset from the runway and enter a downwind for 20. Landing, taxi, and time for lunch and a debrief! (BTW, the restaurant at Watsonville is a tasty Italian place, highly recommend. :) )
