To: (Separate email addresses with commas)
From: (Your email address)
Message: (Optional)
Send
Cancel

Thanks!

Close

Your Elevator Trim Just Jammed. What Should You Do?

Thanks to Bose for making this story possible. Check out the full series here. And if you want to know why we fly with Bose, learn more about their headsets here.
Boldmethod

Control failures are a pilot's worst-case scenario. Here's how you can handle an elevator trim failure...

Your Elevator Trim Just Jammed

Control failures are serious business. And while jammed trim isn't something you'd usually think of as a "dire" situation like losing aileron or elevator authority, it can still be an emergency situation. Fortunately, elevator pitch trim is often an isolated system with separate control cables. The jam shouldn't affect your elevator control directly.

If you continue trimming, your controls might get stuck in a progressively worse, unrecoverable state. Stop trimming immediately (in either direction), maintain aircraft control, and pull out your checklist or POH.

_ Night Flier _

First, Let's Review Trim

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.

Broken pulleys, cables, hydraulics, or even FOD in the cockpit can render a trim system unusable.

The First Step: Slow Down

Trim becomes less effective at slow speeds, so in general, the slower you fly, the easier it is to manage the controls. You'll still have to fly using more manual force than you may be used to, but flying slower than normal in cruise flight will help reduce the strain.

Use Flaps When You Need To

If you're stuck with too much nose-up trim, flaps might help lower the nose of your aircraft. That's because, in many aircraft, increasing flaps causes a nose-down pitching moment.

If you're stuck with too much nose-down trim, adding flaps could have the opposite effect, so you may want to limit your flap use to partial or no flaps.

This is one of the easiest ways you can counter jammed trim, and it will relieve a substantial amount of control pressure you've been maintaining.

Power Changes Can Help Too

Depending on how your airplane is built, changes in power or thrust settings will affect pitch attitude.

An airplane has a low thrust line when the line of thrust passes below the CG. When power is increased, the nose will have a tendency to pitch up in this case.

The opposite occurs when the thrust line passes above the CG. When power is increased in these aircraft, the nose will have a tendency to pitch down.

Keep in mind that trim holds airspeed as well. Generally speaking, as you add power and accelerate, your plane will pitch up to maintain the airspeed you're trimmed for. The opposite is true as you slow down. If you reduce power, you'll decelerate, and your plane will pitch down to maintain airspeed.

Be Prepared For A Go-Around

If you haven't done them before, ask your instructor to demonstrate elevator trim stalls. They're stalls caused by adding full power when flying with substantial nose-up trim, without proper forward pressure on the controls to prevent a high pitch attitude as full power is added.

Imagine flying a perfectly trimmed, hands-off approach to the runway. Elevator trim stalls are supposed to replicate what would happen during a go-around with this kind of trim setting and not enough forward pressure on the yoke. If your trim is jammed, you won't have the option to re-trim, so do your best to anticipate these strong control forces in the event of a missed approach. Add power more gradually than you might with a conventional missed approach.

Has this happened to you? Let us know if you've had problems with a trim system in the comments below.


What are pilots saying about their Bose headsets? Learn more and read the reviews here.


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.

Images Courtesy:

Recommended Stories

Latest Stories

    Load More
    Share on Facebook Share on Twitter Share via Email