The report on the crash of the AirAsia A320 into the Java Sea last year is out and is providing fresh grist for the mill of the anti-tech crowd.
The A320 had a problem with the rudder travel limiter system that was caused by a faulty solder joint. The pilots kept getting warnings from this malfunction. They pulled the circuit breaker, which was prohibited. This disconnected the autopilot and the automatic stall protection system. The crew apparently didn’t know this would happen. The airplane zoomed and rolled into a steep bank. Some time, about nine seconds, elapsed between the start of the roll and any pilot attempt to take control.
The airplane stalled at 37,400 feet and descended out of control to the sea. There was confusion and contradictory flight control inputs from the two pilots on the way down and it did not appear that the stalling condition was fully recognized.
There are enough similarities between this and the Air France A330 that plunged into the Atlantic a while back to lift an eyebrow or two. In both cases, the autopilot disconnected and the crew did not know how to deal with the aftermath. And it both cases it will be said over and over that good basic airmanship would have saved the day.
Before going on, it has to be considered that this latest accident occurred in a land far away and involved a different culture and probably a completely different approach to the art of flying. In the report it was actually stated that the pilots were not trained in upset recoveries because the airplane design prevented it from becoming upset. I would suggest that those folks might want to buy a certain bridge, but they might have already made the purchase.
Some might say that was an airline accident and means nothing to us. That is sticking the old head in the sand because we can learn something from any and all aircraft accidents and over the years private aviation has seen a lot of autopilot-related accidents.
Change the scene to central Florida where the pilot of a Bonanza A36TC was having problems with instructions to stay out of Class B airspace. In explaining why he wasn’t following instructions, the pilot said that he was unable to disconnect the autopilot, that he needed to get the airplane on the ground, and that he needed assistance. Then the pilot told the controller that he had to use “full force” and asked if anyone knew how to turn the autopilot off. An unknown voice on the frequency told him to pull the circuit breaker. The pilot responded that he was pushing as hard as he could on the control yoke and that he had pulled the circuit breaker. The airplane crashed into a lake.
The A320 pilots might not have known that their autopilot would disconnect if they pulled that rudder travel limiter circuit breaker. The A36TC pilot might not have understood the relationship between the autopilot, the electrical trim system, and what is and is not allowed in the certification process. Certainly he apparently did not understand what pulling the autopilot circuit breaker would do, or not do, to help with his problem.
Only one pilot can fly at a time and if the autopilot is flying, the human pilot has to keep his paws off the controls. Why? If you exert elevator pressure, the autopilot will run the trim against that pressure. Pull, for example, for long enough and full nose-down trim will be run. Autopilot certification requirements do not address the power of the airplane’s trim system even though the autopilot uses it and normal pilot strength might not be adequate to overpower a full trim condition.
Can you pull the circuit breaker to fix this? Not completely. Pulling the breaker would only stop the trim from running. Then the manual trim would have to be used to properly retrim the airplane.
That has been true forever and has been written about many times but there will probably always be accidents related to this.
The debates about over-reliance on technology will rage on, too, but I think, in light of these and other accidents, we need to once again step back and examine the relationship between live pilots and autopilots.
In private aviation this all started with the Lear L-2 (sometimes written L2) autopilot. As you may have guessed, this came from the fertile mind of Bill Lear (as in Learjet) and was a remarkable achievement. It was heavy (40 pounds) and expensive for the day but it was a pretty fine autopilot for 1951.
From the beginning, the reaction to a full autopilot, with altitude hold and approach coupling, reflected interesting ideas about the benefits of an autopilot.
A Lear ad in the June, 1951, issue of Air Facts, featured 13 testimonials. One was from Max Karant who was then editorial director of AOPA and would remain active in the organization well into the 1980s.
Max said, “It may well be that Bill Lear has contributed one of the most important missing links to the development of private flying. It is quite conceivable that the L-2 right now could very well boost the average utility of a plane owned by a typical AOPA member from, say, and average of 50% to something like 90%. Such an increase in utility could, by itself, put civil aviation in the position of being one of the nation’s healthiest, more striving industries.”
Other testimonials were equally or more ebullient. From reading them I got the feeling that all these pilots would be getting a new library card so they would have plenty to read while flying along. They said thing like, “Now we can fly 12 hours a day,” and “I no longer hesitate to fly anywhere,” and “Definitely superior to the drive-in theater.” You can conjure up you own double entendre to fit that last one. If you can’t, ask a senior citizen for a little help.
From this it seems that pilots flying with that autopilot felt enabled to do things that they would not, or could not, do without the autopilot. That was, and still is, a potentially dangerous thought.
It was interesting to me that not a lot of editorial ink was given to the L-2. It was straightforward and simple and it flew the airplane well so what else was there to say? In 1951, little thought was given to how to use or to get the most from an autopilot and certainly nothing was said about any pitfalls. It might have seemed like magic but it got surprisingly little attention
Marion Rice Hart was a frequent Air Facts contributor in those days. She was a great friend of Air Facts and wrote many articles about flying her Bonanza all over the world. She did love her L-2 autopilot, too. Her experience with it countered some the arguments from autopilot skeptics.
We were in Dallas, at an NBAA convention. The weather was terrible. Marion showed up, having arrived in her Bonanza. We didn’t really know whether or not she even had an instrument rating. When asked how she had gotten into Love Field in the low weather, she shrugged and said, “Bill Lear flew a perfect approach.” Marion quite obviously depended on that autopilot.
A lot of people were sure the eccentric (and wonderful) old lady would come to an end in her Bonanza. Marion flew until she was 87 and was 98 when she died of natural causes. Maybe an understanding of technology was in her genes because her father founded the Electric Boat Company. The fact that she sailed a 72-foot ketch around the world might have helped her understand risk. She was also a graduate of MIT. The point being that she probably understood what she was doing and the risks she was taking better than most.
My first experience with automatic flight control came in the Piper Pacer I bought from Air Facts (my father) in 1954. It had a Javelin autopilot which was a simple device that detected turn and pushed on the rudder to stop the turn. That wasn’t really an autopilot but it did free up a little time for cockpit chores. Another rudder-only autopilot was the Lear Arcon (automatic rudder control). An ad for that one showed an out-of-control situation on the verge of being fixed by the Arcon.
I only flew with an L-2 a few times and my first extensive experience with more complete autopilots came with Piper house brands (made by Mitchell) called Autocontol and Altimatic. This was in the early 1960s. The goal of these autopilots was to do what an L-2 would do for far less cost.
The Autocontrol was an ailerons-only unit that would hold a heading and the Altimatic controlled pitch as well and had a truly crude altitude-hold feature. Autopilots were becoming popular and while no other airframe manufacturer had a house brand (yet), all were installing autopilots from companies like Tactair, Brittain, Mitchell and others.
I came to quickly distrust the pitch control feature of the Piper Altimatic. It malfunctioned one day and wanted to nose down. I held the airplane level and the autopilot disconnected with a loud pop. I think it had a ball/socket connection in the pitch system that was designed to let go at a certain force. That particular system did not use the airplane’s trim system so once the autopilot was out of the pitch control system things reverted to normal.
My suspicion was heightened when a Comanche was dismantled in flight during a test hop after autopilot maintenance. What could have happened was the pilot allowed the airspeed to build far beyond Va when the autopilot malfunctioned. The overstress of the structure could have come when the autopilot let go and the pilot’s force took over. I decided then that autopilots could indeed be deadly and that prudent risk management suggested a healthy dose of suspicion.
For a number of years, I flew Altimatic-equipped Comanches and Twin Comanches that were leased by Air Facts and I hand-flew them all the way. The first thing I would do on my checklist was pull the autopilot circuit breaker.
When Piper introduced electric trim I had a discussion about it with a person named Piper. He explained it thoroughly including word that some of the system was adapted from technology use on the electric windows of Chrysler cars. That made me forever suspicious of electric trim systems on light airplanes.
I found booby traps in other autopilots, too. I was doing an evaluation trip in an autopilot-equipped Baron and was trying to learn about the autopilot by using it. Trouble was, if you bumped the electric trim control it would disconnect the autopilot and there was no disconnect warning. After realizing that I had unknowingly disconnected the autopilot a few times I just pulled the breaker and hand flew.
My suspicion of autopilots was enhanced when Cessna bought ARC and launched its own brand of avionics and autopilots.
The top-of-the line autopilot was the Cessna 400 and it was installed in most of the demo airplanes that I flew from the 182 through all the piston twins. I didn’t return many to the Cessna factory with the 400 autopilot functioning properly. At best they flew more like a spastic than an automatic pilot and at worst they didn’t work at all. The pitch function was the weakest link and I often suggested to Cessna that they should fix it where the pitch function could be disabled and the roll function could still be used.
My favorite avionics technician once told me that if pilots knew how some of those autopilots were designed and built they would hopefully know not to put any trust in the devices.
If you really want to know how I managed any potential autopilot risks, I’ll tell you. After I went to work for FLYING in 1968, I bought five new or nearly-new airplanes. They were a 182, Cherokee Six, 172, 177RG and P210 Not a single one of them had a full autopilot and none had electric trim. I had every other electronic device known to man at the time I owned the airplanes and treasured having the technology. The last avionics go-around for my P210 put in a Bendix/King IHAS-8000 system that included traffic, weather, ground prox and vertical profile radar. I flew the first-ever GPS approach with a fully approved system in that P210 and when the airplane was retired from service, it had a simple ailerons-only S-TEC autopilot because that was all I wanted. I did think it was necessary to have that much autopilot.
Now the caveat. My thoughts about autopilots were formed in the days of gyros and vacuum systems. Those things in themselves were as low tech as you could get and adapting them to autopilot operation was a stretch at best. The last year that I flew, I used a new Skylane and Columbia 400. Both had a Garmin G1000 and Garmin autopilot. No vacuum and no gyros. I didn’t use the autopilot much in the Skylane because I was used to hand flying regular old Cessnas. I used it more in the 400 because it flew that airplane so well. I learned how to use it for everything and considered it to be far more trustworthy than anything I had used before. Were I younger and buying a new airplane, I might shock everyone by including one of the new autopilots.
Some pretty good safety features have come by way of autopilots, too. Some now have a panic button that will return the wings to level if things are getting out of hand. (The Lear Arcon did that in the 1950s.) Most turbine airplanes have autothrottles which are a wonderful safety device and should actually be on all turbine airplanes.
It is my opinion that the debate over basic airmanship v. high-tech has become confused. Advances in information technology have done wonders for all forms of aviation and should be embraced by all. I think the jury is still out on some forms of automation though autopilots have gotten a lot better. They can still be deadly in the hands of a pilot who doesn’t fully understand the system.
Just yesterday I read of a new Airbus A350 that automatically rejected its inaugural takeoff from JFK because the onboard system decided the runway wasn’t long enough. It did that 18 seconds into the takeoff roll. If the bloody thing had any real sense, and if the runway had really been too short (it wasn’t), you’d think it would have figured that out before starting the takeoff.
Did I use the Killer Autopilots title just to attract attention? No, I used it because misunderstood or malfunctioning autopilots have, for a fact, killed a lot of people, including a wonderful friend and his wife on a dark but not stormy night. I think my suspicion of autopilots and electric trim systems was of great benefit to my risk management efforts over the years.
That’s not to say that others haven’t found benefits, as did Marion Hart years ago. As for the person in the Lear ad who found an autopilot to be definitely superior to a drive-in movie, I’ll leave that risk/reward equation to your imagination.