Mentor Matters: Behind the Magic

This progression makes for a dramatically less-stressful transition into that first jet. Pilots who make the transition to glass simultaneously with their transition into their first jet often opine that mastering the glass is harder than learning to fly the airplane.

However, there can be a downside for pilots who have only known, and become accustomed to, the automation integrated glass cockpits bring. These pilots may become so accustomed to their avionics having all the necessary navigation information automatically displayed that they forget that the “magic” is coming from a computer that only gives the desired output if some vital initial conditions are met. For most flight scenarios those needed preconditions are automatically provided. But on occasion, a small change in those variables produces unexpected results.

At those times, a clear understanding of the hows and whens of the taken-for-granted automation is critical. Without it, the pilot can fall dangerously behind the airplane. I sometimes use the analogy of baking: For many glass-cockpit pilots, flying an instrument procedure is like baking a cake with no idea of how an oven works. Follow the recipe, and the cake comes out great. But for a baker who doesn’t know what an oven does, the fact the oven isn’t heating up because it’s unplugged may not connect to the fact the recipe won’t turn out as desired. Likewise, a pilot who only knows to follow a “recipe” of button pushes and menu selections to get a desired output may not be able to diagnose why this time things didn’t work out.

Here are three areas where pilots can become waylaid during procedures that don’t normally require, or infrequently require, manual intervention with the flight deck.

HSI navigation source selection

Pilots spend most of any given flight looking at “magenta needles”—that is, an HSI displaying RNAV-sourced information. The tremendous accuracy of GPS, combined with the ease of loading thousands of miles worth of waypoints into an auto-sequencing flight plan, has made en route flight referencing VORs largely obsolete. The only time most pilots now see “green needles” (ground-based VOR navaid signals) on their HSI displays is during the last 10 miles of an ILS approach.

The switch from magenta to green is handled smoothly by the flight deck, with no direct pilot intervention typically needed. But pilots must understand why the automatic transfer occurs. In some flight decks it’s a function of activating the approach mode of the autopilot. In most, the switch won’t occur until the airplane has crossed the fix immediately before the final approach fix (FAF). I’ve previously written about how this detail can combine with errors in navigation database coding (for example, an FAF that wasn’t marked as such in the Caribbean), or unusual approach geometry (an ILS into Chicago’s Midway airport with very short final and intermediate approach segment legs), to surprise pilots and leave them too high on the ILS, unable to couple to the approach’s glideslope.

Understanding how and why the reverse transition—green needles to magenta—occurs is just as important. On a missed approach from an ILS, getting magenta needles displayed quickly is essential to a smoothly flown missed. For many light jets this function occurs with the push of power lever-mounted go-around buttons, but on some flight decks a deliberate button push is needed.

Approach frequency selection

If green needles are needed, a proper frequency is a must-have. Again, many flight decks will automatically tune and select the correct ILS frequency to the active position after the approach is loaded. However, most flight decks will not do this if the approach is loaded while green needles are being viewed. The reasoning is, the pilot most likely is using that HSI for current guidance, and replacing the active frequency may not be appreciated.

This can create a complication when a pilot attempts to change to a new ILS frequency after one has already been loaded and activated. The pilot may be so accustomed to the act of loading the ILS causing the correct ILS setup to appear that they aren’t in the habit of double checking—and don’t catch that the wrong frequency and course are displayed.

HSI course selection

A final automation gotcha relates to the auto-slewing of the HSI to the correct course for the active leg. When on GPS guidance, a pilot almost never needs to adjust the HSI course, as it’s automatically driven by the FMS. Similarly, on an ILS approach, loading the approach seems to magically set the HSI to the proper course. Yet this course information is coming from a database in the flight deck, and it’s subject to errors. Courses have been inverted 180 degrees in databases, causing reverse sensing if the pilot does not catch the issue and manually corrects the course.

Alternatively, at many airports with an ILS to both ends of a runway, one frequency is used for both approaches, requiring the flight deck to “guess” which one will be flown. Most of the time the guess is correct, based on the loaded approach and/or aircraft position relative to the airport. But in a case where an airplane is flying an ILS without having loaded the approach, and approaching from what the flight deck thinks is the “wrong” side, the deck may again display a course 180 degrees from the one needed.

The cited examples illustrate two important lessons. First, pilots must guard against complacency, assuming the automation will always do what’s needed, and must be mindful of the conditions that lead to the desired output. This requires continuously examining the current state of the aircraft, and asking if anything differs from the norm.

Second, and more important, for every situation in which the “magic” of automation is supposed to create a desired state but doesn’t, pilots should be able to quickly revert to a manual workaround. If the magenta-to-green needle transition doesn’t occur, be prepared to quickly press the CDI softkey on a Garmin flight deck—or know the proper button sequence required on other flight decks, as in some cases multiple steps are needed to force a navigation source switch. If the ILS frequency doesn’t auto-tune, be prepared to manually enter it and transfer it to the active side. Many pilots may not have performed this simple action in months, if not longer. And if the course deviation indicator doesn’t auto-slew to the correct final approach course, be ready to quickly set it manually using the course knob.

All are relatively simple actions, but ones that aren’t executed frequently. That means you should practice manual workarounds to proficiency. Recognize a problem early, fix it quickly, and life is good. Being unprepared and caught by surprise at a stressful time is a recipe for panic.

Neil Singer is a Master CFI with more than 8,500 hours.