Review both pages of the LINDZ# departure. By now, you should be familiar with picking out the key points:
- The top altitude is 16,000 ft. MSL.
- The departure is only applicable from Runway 33 (and requires a minimum climb gradient of 465 ft. per NM to 10,000 ft. MSL). Runway 15 departures are not approved, due to terrain.
You may also recognize this as a pilot navigation departure, which takes the aircraft directly from the runway to the enroute environment without a requirement for ATC instruction. However, unlike when we flew the ALPIN# pilot navigation SID at KJAC, this one involves a back course.
In order to understand the reasoning behind a back course approach, it’s first important to discuss how localizers work. Unlike VORs, localizers only have one radial and only transmit a signal in a single direction. Therefore, when flying an ILS approach, the needle behaves the same regardless of what course heading you have selected.
Historically, smaller airports used a localizer that transmits a signal forwards and backwards so that horizontal guidance could be given for both sides of the runway from a single installation. This allowed for cost savings. However, upgraded technology (i.e., RNAV approaches) have mostly eliminated the need to serve multiple runways with a single installation. In fact, as of summer 2020, there were only 64 back course approaches left in the United States—that’s less than 0.4% of the available approaches published by the FAA. Depending on your aircraft’s navigational equipment, flying a back course approach could mean you are dealing with a "reverse sensing" localizer: when a course deviation indicator (CDI) tells you to turn right, you actually turn left. In other words, you would turn in the opposite direction you think you need to in order to remain centered on the localizer.
Fortunately, the designers of the LINDZ# departure at KASE decided to avoid this complexity. As you can see on the chart, a note clarifies that "I-PKN back course outbound is normal sensing". In other words, when you join the "localizer" on this departure, it works just like an ILS...except it’s designed to point you away from the airport instead of toward it!
To fly the LINDZ# departure, start by setting up the airplane. Tune your navigation radio to the localizer frequency (108.50) and set the course to 303° (although tracking the localizer won’t technically be affected by your course setting, having it set correctly aids in situational awareness). You’ll need to be able to intercept this localizer when you get airborne.
Take off from Runway 33 and make a right turn to a heading of 343°. When IMC, it’s standard practice to fly the runway track until at least 400 ft. AGL before making any turns, so most IFR pilots will maintain the centerline until 400 ft. AGL, then turn right to 343°. Climb to 9,100 ft. MSL and then turn left to heading 273°. Fly that 273° heading until you intercept the localizer and are tracking it outbound. Because the back course is "normal sensing", the localizer works just like an ILS: if the needle tells you to turn left, you are right of course and need to turn left to re-join. You’ll track the localizer until reaching LINDZ, which you can identify:
- With your GPS or FMS.
- By the intersection of the localizer and the DBL R-244.
- By 13 DME from the DBL VOR.
Reaching LINDZ, you can switch to GPS navigation and track directly to IDENE and then follow the remainder of the flight plan. For terrain, you’ll want to reach LINDZ at 14,000 ft. MSL or higher, and then leave IDENE above 16,400 ft. MSL. A good cruising altitude for this route is the one SkyWest’s pilots use: FL230.
If you’re flying an advanced aircraft with updated navigation data, chances are this entire departure is built into your FMS with GPS waypoints. You may be able to load the departure and fly it entirely using the FMS/GPS and in fact it’s legal to fly it without even having the localizer tuned. However, it’s certainly a good practice to have the localizer tuned even when you don’t plan to use it, especially when you’re flying in actual IMC.