by Capt. Michael J. “Mick” Kaufman
Published in Midwest Flyer – April/May 2020 issue
When doing instrument flight training in Instrument Meteorological Conditions (IMC), one can never know what to expect. I have in previous columns emphasized the importance of being able to hand fly an approach in IMC, but never thought of needing four hands to do it.
To give our readers a better insight into some shortcomings of autopilots, I am passing on some information that may save your life. The following incident occurred at a recent flight training clinic I was managing.
The airplane was a Beech Baron, the departure airport was Lakeland Linder International (KLAL) in Lakeland, Florida, and both the pilot and instructor were very experienced.
The weather for their departure was well above the minimum standard of circling minimums, which is the criteria we use at our training programs.
Because the weather was marginal, the pilot and instructor decided to concentrate the training on practicing instrument approaches in low IMC conditions. Brooksville-Tampa Bay Regional Airport (KBKV) became the destination, and the selected approach was the ILS for Runway 09.
The pilot was flying an autopilot-coupled approach after several previous approaches to the same runway. Upon reaching the published minimums for the approach and seeing nothing at minimums, the pilot decided to go missed.
The procedure is to disconnect the autopilot with a sequence of power up, pitch up, positive rate, gear up, flaps up and climb to the published altitude on the approach chart or alternate missed instructions from Air Traffic Control (ATC). All went well starting with the disconnect of the autopilot, which was a King KFC 200 with a flight director, but the pilot could not raise the nose, and requested assistance from the instructor. The Baron has heavy elevator forces, and it took two pilots pulling on the yokes to establish a climb. The manual trim wheel was frozen, and it was pure muscle on the yokes from both pilots that kept the aircraft in a climb. After reaching a safe altitude and continuing to fight with an out-of-trim condition, the pilots decided to reactivate the electric trim as the manual trim was still frozen, and it worked!
What could have caused this condition in the first place? After flying around for some 30-plus minutes trying to figure out what had gone wrong, the pilots returned to Lakeland just as the weather cleared and landed safely.
We may ask ourselves, what if this happened to me, and I was all alone in the aircraft? Would the conclusion be labeled as “pilot error” if an accident occurred? How could this situation be prevented, or could it?
After landing, the pilot and instructor tried numerous times to duplicate the incident on the ground with no satisfaction – everything worked as normal. This was an anomaly and oftentimes we never do determine what causes something to happen with this or similar situations, but we must recognize that it could happen on a future flight.
The first thought from an autopilot expert led the aircraft owner to suspect that the trim servo clutch had malfunctioned, so he had the clutch examined at the avionics shop, which confirmed it was the clutch.
I have never seen the inside of an autopilot clutch, nor do I know exactly how it is supposed to work, but in this case, it was described as a broken gear tooth that caused the trim to jam.
It is important for pilots to become familiar with their autopilots and to read the autopilot supplement in their aircraft pilot operating handbook (POH). The POH will give ways to test the autopilot, and it needs to be noted that these tests are different among autopilots. There is a safety clutch on most of the autopilot servos that I am familiar with, which should be able to be overridden by the pilot and checked at periodic intervals.
Some autopilots have a disconnect on the yoke, some will disconnect if the electric trim is activated by the pilot while on autopilot, and some aircraft with flight directors on their autopilots will have a “Go Around” (GA) button, which will leave the flight director function working, while disconnecting the power to the servos. This is a great tool that will set a predetermined pitch attitude for a go around.
Another option with or without a flight director is “control wheel steering” (CWS), which will momentarily disconnect the autopilot to allow the pilot to make small altitude changes or make a momentary pitch or roll change without disconnecting the autopilot. While training, I find pilots who have owned a particular aircraft for years and never knew how to use the CWS button.
Fly safe, and for those of us living in the Midwest, we look forward to some great spring flying weather!
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. Kaufman conducts pilot clinics and specialized instruction throughout the U.S. in a variety of aircraft, which are equipped with a variety of avionics, although he is based in Lone Rock (KLNR) and Eagle River (KEGV), Wisconsin. Kaufman was named “FAA’s Safety Team Representative of the Year” for Wisconsin in 2008. Email questions to email@example.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.