by Michael J. “Mick” Kaufman
© Copyright 2024. All rights reserved!
Published in Midwest Flyer Magazine June/July 2024 Digital Issue
So why would anyone want to do a “localizer back course approach” with area navigation route (RNAV) global positioning system (GPS) approaches now serving almost every public airport runway? I even hear this question when I suggest we do an instrument landing system (ILS) approach on an instrument proficiency check (IPC). There are numerous back course approaches available in the area where I train pilots for instrument ratings, and pilot examiners love to include one on the check-ride if it is in the area where the check-ride is given.
To begin this article, I should explain what a back course is and why I was inspired to choose this as a topic for my column in this issue.
First, every instrument landing system (ILS) or localizer (LOC) approach generates a back course as part of the radio signal that makes up the front courses of these approaches. However, not every one of the signals from a back course are usable to create an approach.
Going back a decade or more before the advent of GPS navigators (nav/coms), pilots had a better understanding of the ILS and back course approaches. If we did not have a horizontal situation indicator (HSI), we had a rule that flying inbound on a back course or outbound on the front course had reverse needle sensing. So, we fly away from the course deviation needle, rather than towards the needle. It sounds easy, but the human brain intervened, and pilots got confused.
Then along came the Terra “tri-nav indicator” with a back course button. I had one in my Bonanza, but took it out with my last avionics upgrade (a mistake). If your pocketbook could afford an HSI, which costs about five aviation monetary units (AMU = $1000.00), which was real money at the time, you had it made. With an HSI, you input the front course of the localizer, and you could never get reverse needle sensing. Today, we have modern GPS navigators that take the guesswork out of setting up the approaches we fly.
A few days ago, I had the opportunity to fly with a pilot in his beautiful Piper Lance, and while instructing him for his instrument rating, I became inspired to write this article.
Prior to seeing and using the avionics in the student’s airplane, setting up a GPS navigator and autopilot to fly a back course approach was a “button-ology” disaster.
First, the GPS needed to have the airport and then the approach selected in the navigator box, followed by the initial approach fix (IAF) or a published transition for the back course approach. The frequency for the localizer needed to be in the active frequency box on the navigator, and the approach was activated.
All went well until the aircraft was established inbound with GPS-S (steering) engaged. It was now necessary to set the heading bug to the inbound back course track and select “heading” on the autopilot to keep the aircraft from turning while button-ology was in progress. The pilot now needed to switch the navigator from GPS to the VLOC (VOR/ Localizer) frequency, rotate the HSI needle 180 degrees manually to the direction of the front course, and select the reverse nav button on the autopilot. This process was so different than on any other type of approach, so pilots screwed this up more times than they got it right.
Enter in updated avionics and firmware and repeat the above approach. The avionics used were a Garmin GNS 430, two Garmin G-5 indicators and a Garmin GFC-500 autopilot with envelope protection.
The approach was entered into the Garmin 430 navigator with an initial approach fix (IAF) or transition as previously described above, followed by moving the localizer frequency to the active window. The autopilot was engaged in the NAV mode, and the route was flown, until we found ourselves established inbound to the airport on the back course. We then switched the GPS navigator from GPS to VLOC and pushed the NAV button on the GFC-500 autopilot. What is different is that pushing the GPS/VLOC button causes the Garmin G5 to auto slew 180 degrees, which is correct. The autopilot is disconnected automatically and when re-engaged, it is flying the LOC signal correctly with reverse input sensing.
I am happy to see that some much-needed improvements are taking place in our avionics to simplify doing a back course approach. For those readers who think they will never do a back course approach, there still is a lesson to be learned.
In many GPS navigators, the pilot has the option to have the GPS navigator auto select VLOC without pilot input. I do not recommend this as some autopilots will turn off during the switching process as I mentioned above, catching the pilot off-guard and the aircraft off-course.
Every pilot needs to know what is going to happen in the exact aircraft they fly. A Garmin GFC-500 in a Bonanza may behave differently in a Cessna 182 with identical supporting avionics. In the Piper Lance, a missed approach begins with the pilot pushing the go-around button and pushing the throttle full forward simultaneously. The autopilot, if on, will not disconnect, and the aircraft will pitch to a factory preset angle, and the autopilot envelope protection will not let the aircraft stall if the pilot forgets the throttle (not forgivable). The go-around button does disconnect autopilot navigation, so pushing the NAV button on the GFC-500 autopilot will cause the aircraft to fly outbound on the front course. If the pilot switches from VLOC to GPS prior to engaging NAV on the autopilot, it will fly the published missed approach with the hold. If the pilot had set the altitude bug on the autopilot to the missed approach/holding altitude prior to or after pushing the go-around button, the aircraft would level at that altitude. If a turn was part of the missed approach procedure prior to reaching the holding fix and altitude and the aircraft was equipped with an air-data computer, a turn would be made at that point. All of these items should be checked by the pilot prior to flying in instrument meteorological conditions (IMC) with each aircraft he/she flies or when coming out of any maintenance.
From my article in the June/July 2024 issue of Midwest Flyer Magazine, we have not found any issue that had caused us to put the autopilot on probation.
I have continued to work with the ForeFlight app using the Apple Vision Pro under a very safe and controlled environment. It is very promising at this point. I see a future for use in the cockpit and may be a future signoff or checkride item, as there is for night vision goggles or heads-up displays. I urge you to exercise good judgement and have a safety pilot or instructor onboard should you decide to experiment. When we went from paper to electronic charts, it took a while for them to be accepted as a safe alternative.
Please fly safe and look for more updates in the next issue of Midwest Flyer Magazine.
EDITOR’S NOTE: Michael J. “Mick” Kaufman is a Certified Instrument Flight Instructor (CFII) and the program manager of flight operations with the “Bonanza/Baron Pilot Training” organization. He conducts pilot clinics and specialized instruction throughout the U.S. in many makes and models of aircraft, which are equipped with a variety of avionics. Mick is based in Richland Center (93C) and Eagle River, Wisconsin (KEGV). He was named “FAA’s Safety Team Representative of the Year” for Wisconsin in 2008. Readers are encouraged to email questions to captmick@me.com, or call
817-988-0174.
DISCLAIMER: The information contained in this column is the expressed opinion of the author only, and readers are advised to seek the advice of their personal flight instructor and others, and refer to the Federal Aviation Regulations, FAA Aeronautical Information Manual, and instructional materials before attempting any procedures discussed herein.
