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A Loose iPad Jammed This Pilot's Trim Wheel, Leading To An Emergency Landing

Have you ever dropped your iPad in the cockpit. What would you do if this happened to you?

But First... A Review Of What Trim Does

Trim holds airspeed. If you trim for a speed and let go of the yoke, your plane will keep flying at that speed, regardless of your power setting. If you trim and change your power, your plane will pitch up or down to maintain your trimmed speed. Trim for climb speed, let go, and you'll maintain climb speed. Trim for cruise, let go, and it'll maintain cruise speed. Trim for final approach speed, let go, and you'll maintain final approach speed. The list goes on. Trim holds airspeed.

Trim systems can fail. Broken pulleys, lines, hydraulics, or even FOD in the cockpit can render a trim system useless. A trim runaway happens when an un-commanded trim setting progresses. If left unchecked, it can render an airplane nearly uncontrollable. This is a big deal, especially for jets flying at high speeds with large control forces.

Corporate Flight Crew Declares An Emergency

We found the following NASA ASRS report which details a jammed trim wheel leading to an emergency landing. This experienced crew was flying a light corporate jet...

Upon descent, between four thousand and ten thousand feet, an annunciation "Master Caution" illuminated with "AP Mistrim" illuminated. After the Master Caution switch was pressed the annunciation extinguished shortly after. The Captain (flying pilot) pressed and held down the AP disconnect button, disconnecting the AP. He then tried to manually trim the aircraft and the elevator trim wheel was jammed and would not move.

At this point, he asked me (first officer; non-flying pilot) to declare an emergency, request ground equipment to be standing by. He then instructed me to run the checklist. I proceeded to run the checklist for both AP Mistrim annunciation and then trim controls jammed. The Captain landed the aircraft safely and we taxied to the FBO. After deplaning the aircraft, the Captain went back in the aircraft to troubleshoot the problem with the power ON. First with the electronic trim then manually. Upon doing so the Captain noticed something was moving underneath the trim wheel. During the descent, an iPad got lodged underneath the trim wheel and jammed the trim wheel. To prevent this from happening in the future, I suggest having the pilot's side pockets to be utilized for iPads, and the pilots rear pockets used for the checklist. This would prevent an iPad from sliding underneath the trim wheel and jamming the trim controls.

J Pixx

Flying With Jammed Trim

What should you do if your trim is jammed? First, transfer the flight controls to another pilot (when able) and try to locate any FOD in the cockpit. Before continuing to test the trim, follow your emergency/abnormal checklist. If you continue trimming, you make stick the controls in a progressively worse, unrecoverable state.

You'll have to fly using more manual force than you may be used to. If you're stuck with too much nose-up trim, flaps will help lower the nose as the aircraft flies at a smaller AOA. With too much nose-down trim, adding flaps could have the opposite effect.

Danger Of FOD In The Cockpit

We've all heard the dangers of FOD on the runway. The posters of FOD debris and damage are a common sight in FBOs and flight schools across the country. But how about in the cockpit? Do you strap down all of the luggage? How about your flight bag and your iPad?

There's a lot that can come loose and interfere with flight controls, even you EFB. Thankfully, this iPad didn't manage to disable something as critical as the elevator or ailerons. If you can use a solid mount or kneeboard, that's a much safer alternative than holding your iPad freely.

Have you ever had FOD in the cockpit or a jammed trim system? Tell us in the comments below.

Swayne Martin

Swayne is an editor at Boldmethod, certified flight instructor, and an Embraer 145 First Officer for a regional airline. He graduated as an aviation major from the University of North Dakota in 2018, holds a PIC Type Rating for Cessna Citation Jets (CE-525), and is a former pilot for Mokulele Airlines. He's the author of articles, quizzes and lists on Boldmethod every week. You can reach Swayne at swayne@boldmethod.com, and follow his flying adventures on his YouTube Channel.

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