There was initial confusion on the part of a ground controller who sounded like one of many new arrivals to Oakland's North Tower. We'd briefed the VFR transition over the San Mateo Bridge mid-span prior to starting the engine. The briefing included the transition from Oakland's North Field over the South Field, the importance of staying well clear of San Francisco's Class B surface area as well as underneath the overlying Class B, and the existence of a defined VFR waypoint (VPMID) for the San Mateo Bridge mid-span. I'd said to plan for an initial altitude restriction of 1400 feet, but the new ground controller (who was also working tower) gave us a 2000 foot restriction. When handed off to the South Tower at 900 feet, the South Tower controller (a seasoned veteran) queried "Were you given an altitude restriction?" When we told her 2000 feet, she corrected that to 1400 feet.
A few minutes later, we were handed off to the first of several Norcal sectors and were gradually allowed to climb higher as we motored over the Sunken Ship, past Palo Alto and over Moffett Federal Air Field (a former Naval Air Station). A few minutes later, the Lexington Reservoir was beneath us and a bit later, just clear of the Santa Cruz Mountains, we began the descent just to the east of Capitola.
My student had told Norcal that we were "direct NALLS for a practice Localizer 2 approach into Watsonville, with the one-minute weather." The plan was to do the procedure turn on our own navigation, fly the approach to as close to minima as the VFR traffic at Watsonville would allow, then fly the published missed approach and hold over Salinas (a holding pattern I know all too well). After the holding pattern, we planned to fly the GPS A approach because it offers a DME arc and there are precious few of those in Northern California that are also close to the Bay Area.
As we were outbound in the procedure turn, I remembered why the LOC RWY 2 approach sets off my spidey senses: We were beyond gliding distance from the shoreline, over waters frequented by great white sharks, in a single-engine piston aircraft. So I distracted myself by looking for traffic and pondering the other instrument approaches into Watsonville.
If the coastal stratus has blown in, the Localizer RWY 2 approach may be your only real hope of getting into Watsonville because it is the only approach that will probably get you below the clouds - 680' MSL. There is an NDB or GPS B approach that is lined up with runway 2 that gets you almost as low as the Localizer approach - 900' MSL. The VOR/DME or GPS A approach from the southeast that only gets you down to 1300 feet, which is often just above the tops of the stratus layer.
When flying an aircraft with a WAAS-enabled GPS receiver, the WVI GPS B approach is in some ways more attractive than the Localizer RWY 2 approach. One reason is that the G1000 will provide you with a vertical track on the GPS B approach down to the final approach fix (FAF). After the FAF there's no descent guidance on the GPS B, but you don't get any descent guidance whatsoever with the localizer approach. The other advantage of the GPS B approach is you needn't end up as far out to sea when you make your procedure turn as you probably will with the LOC RWY 2 approach.
There are probably many other cases where a RNAV (or GPS) approach gets you lower or offers advantages over a localizer approach - South Lake Tahoe comes to mind. So when you are considering which approach to fly into an airport, don't forget to examine all your options. The advantages of one approach over another is not always as simple as it seems.
