AD Mandates Garmin Autopilot Software Fix


On Oct. 6, the FAA proposed a new airworthiness directive requiring operators of thousands of aircraft to update Garmin autopilot software to address a flaw causing the autopilot to make unintended flight-control inputs.

According to the agency, the AD was issued in response to an incident involving an F33A Bonanza experiencing “an un-commanded automatic pitch trim runaway when the autopilot was first engaged.”

The proposed rule states: “The affected autopilot system software does not properly handle certain hardware failures of the pitch trim servo. This could result in an automatic uncommanded pitch trim runaway and loss of control of the airplane.”

The FAA estimates the AD would affect 5,900 aircraft equipped with the autopilot system— including Beechcraft Bonanzas, Commander Aircraft 112s and 114s, Cessna 172s, 182s, 206 and 210s, along with Daher TB20s and TB21s, Mooney’s M20 series and Piper Cherokees. However, the FAA estimates a fix will be relatively cheap for operators at around $85.

The agency is proposing operators complete the installation of the updated Garmin autopilot software within a one-year time frame. The proposed rule will be published on Oct. 10, and the FAA will accept public comment until Nov. 24.

Meanwhile, many of those affected have already resolved the issue since Garmin released the software fix earlier this year. “The updated GFC 500 software for GI 275, G5 and G3X Touch installations allows pitch trim to be enabled as a closing action to Service Alert 22109 and STC Service Bulletin 22110,” Garmin said in a statement to AVweb. “The Aviation Service Document Notification describes the software update procedures for impacted owners and operators.

Amelia Walsh
Amelia Walsh is a private pilot who enjoys flying her family’s Columbia 350. She is based in Colorado and loves all things outdoors including skiing, hiking, and camping.

Other AVwebflash Articles


  1. So not only has Garmin managed to produce a product that can actively try to kill you, but you have to pay for the fix as well? You would have thought that the pre-release testing process would have included some extensive “what if” scenarios including the fairly obvious servo failure modes. How does this kind of failure get through the net? We are placing life and limb in the hands of software coders in more and more ways…I guess we pays the money we takes the choice.

    • Spoken like a guy that can’t afford this equipment. I could name off a thousand ADs across an entire spectrum of airplanes. This is an easy fix. It’s software related. You should stick to paper airplanes.

    • From your BTI address, and the fact that you are the first to post, it would be easy to speculate that you live in England. But $85 is not an uncommon landing fee there, so you should be used to a more coddling government and much more expensive personal flying.

      In case you haven’t noticed, every manufacturer of aircraft (and related products) releases things that are trying to kill us; that’s the nature of the our activity. But your umbrage tells me that you’ve never worked in the software, pharmaceutical, childrens’ toys, or frankly, any other industry that offers a product to the public. Failures sneak through even the most exhaustive of pre-release testing, otherwise there would be no need for the Part 39 regs regarding AD notes, obviously. Or the US Consumer Product Safety Commission, for that matter.

      In this case, it wasn’t so much a failure in the autopilot per se, as a failure of it to recognize a failure in an external component. That raises the number of acceptance tests (and ultimate product price) exponentially. And Garmin released the fix for free. That chump-change estimate of $85 is the FAA’s best guess of what it should cost to have an avionics shop do it for you. I just paid more than that to buy an inner-tube for one 6.00-6 tire on my C172.

      Which doesn’t have an autopilot, so I don’t have dog in this fight. But then, for some reason, I suspect you don’t either.

    • The $85 is an estimate. It’s certified gear, so you can’t legally do the upgrade yourself, which means paying a certified installer to do the update. I’d expect that Garmin itself isn’t making anything on this and the cost is just for the installer’s time (including signing log books saying that the work is done).

      Man, how I wish all my airplane problems were just $100 each.

  2. So Garmin can produce autopilots with significant operational software bugs. Garmin gets rapid FAA make/model approval for its autopilot while other autopilot potential competitors languish for years.

    I put a dynon autopilot in my C182 and waited almost 4 years for the approval after the C172 was approved. I think Trig and the other companies face the same years long approval process.

    What gives?

    • Garmin has more money for testing, to push approval. That simple.
      Also, having written software for USAF and others, the number of scenarios that cannot be tested for is closer to infinity than the numbers that can best tested, at least within one lifetime.

      • So what you are saying is that Garmin’s software cannot be tested while the others cannot be approved for the same reasons? Or are you saying Garmin has the money to push (incentivize) FAA approval while the others have to wait for the FAA?

    • Exactly. Dynon has did all the testing on my airframe 2 years ago, and just sits, and waits. While Garmin has spit out over a hundred. It’s a political monopoly. Follow the money

  3. Garmin has already dealt with this earlier this year with a software fix at no cost through a SB release.

    The “what if” scenario you particularly refer to is covered in the AFMS.

  4. I find it interesting that the AD estimates the cost at one hour = $85… did I miss something and one can get aviation MX done in the US for an average (!) of $85..?

  5. Save the Garmin criticisms for not supporting legacy equipment, or not giving other companies the help to support them.

    • But it did include a link to the proposed AD, which states: “This proposed AD would require updating the applicable Garmin GFC 500 Autopilot System software for your airplane and would prohibit installing earlier versions of that software. “