Sim Challenge 3: Pitch Imperfect (VFR)

Flight control failures are tough to practice in real airplanes, so we’ve collected a few of them for you to fly in your simulator.

Let’s say you’re flying along and ease back on the yoke and … nothing happens. Or your pitch trim is a bit over-enthusiastic and keeps on spinning after you release the switch on the yoke. Misbehaving flight controls are rare enough that most pilots will never encounter one. But it’s really bad news when they do, and chances are that the pilot is dealing with it for the first time. You can’t truly practice failed primary controls in an airplane, so pilots make do hoping they’ll know what they’re supposed to do.

That gap between knowing and doing is what this Sim Challenge is for. You’ll systematically mess with your primary and secondary flight controls over Bellingham, WA (KBLI), and practice your workarounds using the controls that you still have.

You’ll start with something subtle: your airplane just came back from the shop, and somebody ran the nose-up trim to the stop during maintenance. You didn’t catch it during your preflight … or your before takeoff checklist … so now you’ll find out about it on the takeoff roll.

Fair warning: These exercises are tough and might end badly for you. That’s fine. The training objective for today is awareness, not ACS standards. It’s better to try to figure it out here than on a bad day in a real airplane.

Time to Fly: ~30 minutes

Aircraft Used: Any single-engine or light twin (Cessna 172, Cirrus SR22, Beech Baron, etc.)

Tasks:

Depart with elevator trim mis-set (full nose-up)
Maneuver with trim full nose up
Attempt to land
Depart normally
Reset trim to full nose down
Maneuver with trim full nose down
Attempt to land
Depart with no elevator or aileron control (no yoke)
Maneuver without elevator and ailerons
Attempt to land

Skills Practiced:

Trim runaway recognition, control, and recovery
Pitch control using trim and power alone
Roll control with rudder alone
Degraded-control approach and landing

Fly with Nose-Up Trim

CONFIGURE THE SIMULATOR

Position: Bellingham International (KBLI), Runway 16, ready for departure.

Time: Midday

Weather Settings:

Sky Condition: Clear
Visibility: Unlimited
Wind: Calm
Temperature: Standard

Simple weather, since you don’t need to make this challenge any tougher than it already is.

Other:

Set full nose-up trim

UN-PAUSE THE SIMULATOR

Depart Runway 16 and climb southbound. Leave the trim alone during the climbout. (Did you hear the stall horn chirp a few times?)
Make a 90° turn to the right, then 90° to the left, while climbing.
At 1000 feet, reduce power until you hold level flight. As you do the next steps, turn as needed to stay near KBLI.
Experiment a bit with reducing and adding power in small increments to change your rate of climb or descent
Experiment with extension and retraction of flaps and/or gear.
Return to the airport and set up to land. Do this from a standard pattern or long straight-in, as you see fit.
Go around (Even if it’s looking good. This is part of the challenge.)
Come back around for a pattern or long straight in.
Attempt to land.

If at any time you lose control and crash, go back to step 1 and start over.

PAUSE THE SIMULATOR AND DEBRIEF

Nose-up Trim Debrief

Question 1: You just managed to take off with full nose-up trim. Why didn’t the airplane just continue pitching up into a stall?

Well, it might have. It depends on the aircraft and situation. We usually think of pitch trim as the thing that takes the pressure off the yoke while you’re hand-flying. But consider what it’s actually doing to accomplish that: it’s positioning the elevator by itself. (Yes, servo-tab trim systems hold the elevator in position differently than anti-servo trim systems hold a stabilator, but the main pitch control is held in place aerodynamically one way or another.)

In trimmed, hands-off flight, you don’t hold in control force because the pitch trim is doing it for you: It’s effectively the pitch control. However, it might not have enough authority to fully deflect the controls. It usually doesn’t.

Question 2: What could you do to control pitch if you were struggling to keep the nose from pitching up?

It’s counterintuitive, but roll into a bank. The immediate problem is with pitch, so your instincts are telling you to fix it on the pitch axis. But if you’re losing that battle, you need to think outside of the box a bit. When you bank, the vertical component of your lift decreases. At 45 degrees of bank, only about 70% of your lift is working against gravity. At 60 degrees, that becomes half.

If you roll into a bank, the trim-induced pitch-up force that’s winning the fight on the elevator will be pointed partially sideways instead of straight up, allowing your climb rate to drop and your airspeed to stabilize. This is a bandage rather than a cure, since the pitch issue remains and you can’t hold a steep turn all day long. However, it does give you some time to attempt to remedy the underlying trim issue, or at least think and troubleshoot without the aircraft heading toward a stall. Just make sure you don’t put yourself into a worse unusual attitude than you’re already in.

Question 3: How did that go around go?

With full nose-up trim, full power is going to induce a wild pitch up ride. If you picked something with lots of power or added power too quickly, this could cause a roll over if you get uncoordinated. You’ll need a smooth application of power and proper rudder use. The retraction of flaps (if you had any out) must happen in small steps so the airplane can stabilize in between. At least you still have the primary pitch control available to you.

Fly with Runaway Trim

For the next exercise, you’re going to simulate a trim runaway, see how long it takes to hit the stop, and then see what it’s like to fly with it there.

Note: Be on the lookout for the nose lowering and act quickly with the yoke to maintain level flight. In a real airplane, as long as you’re strong enough to overpower the trim force, you could maintain control. You just might have to be REALLY strong. A simulator interprets joystick inputs differently though, so once a dive develops it will probably be impossible to recover.

RECONFIGURE THE SIMULATOR

Elevator: Normal
Ailerons: Normal
Rudder: Normal
Trim: Normal (you’ll trigger the runaway manually)

UN-PAUSE THE SIMULATOR

Depart Runway 16 and climb southbound.
Level off at 3000 feet.
Trigger the runaway. Hold nose-down trim until it hits the limit and see how long it takes.
Let it run. Notice how the plane responds and don’t fight it.
Now fly the airplane. With trim stuck at full nose-down deflection, climb 500 feet and descend back to 3000 feet.
Make a 90° turn each direction while maintaining altitude.

If at any time you lose control and crash, go back to step 1 and start over.

PAUSE THE SIMULATOR AND DEBRIEF

Nose-down Trim Debrief

Question 4: What might that feel like in the real airplane?

In a real airplane, you’d be muscling the yoke the entire time, and that constant effort makes fine pitch adjustments difficult. Pure fatigue will set in quickly. If these exercises felt manageable, that’s the sim’s light control forces talking, not the situations. Typical GA aircraft could need 50 pounds of stick force. There are aircraft where full nose-down trim would require putting your feet on the panel and pulling back on the yoke with both hands … which makes it pretty hard to fly.

Let the nose drop and the control force needed will increase exponentially as airspeed builds. The longer a runaway develops, the more control force is needed to counteract it. Catch it quickly and try to slow down to keep the forces manageable. And don’t skip arm day at the gym.

Question 5: Your trim is running away nose-down. What do you do?

A trim runaway happens when anything from a stuck switch to a faulty servo runs the electric trim without being asked to. If you’re flying along with the autopilot engaged, and the trim runs away, the autopilot will mask the problem—at least for a while. You might not notice it until the autopilot disconnects, handing you a barely controllable airplane with no warning. Depending on the airplane, trim can drive from neutral to its limit in a matter of seconds. Consider it a time-critical emergency.

You must know the various ways to disable the electric trim and autopilot. Usually, there’s a trim switch on the panel and a circuit breaker. The system is usually incorporated into an autopilot, if one is installed, so interrupting the autopilot will hopefully interrupt the electric pitch trim. That could be the autopilot disconnect switch on the yoke, autopilot switch on the panel, or the autopilot circuit breaker (it’s the pullable kind, right?). If that doesn’t work, turning off the avionics master switch or even the battery master switch may be warranted. Note that some electric trim systems only temporally disconnect when you hold the yoke button in. Let go and they can start running away again.

Question 6: You just recovered from a nose-down runaway. How does the nose-up out of trim situation from before compare?

Nose-down trim runaways are a self-reinforcing feedback loop where the nose drops, speed builds up, the control forces increase exponentially, making it harder to physically overcome, causing speed to continue to build.

With a nose-up out-of-trim situation, the physics is somewhat working in your favor. As the nose rises, speed bleeds off, reducing required control forces, but eventually the aircraft will stall (and possibly spin).

That doesn’t sound fun either, but it’s not the same emergency as nose-down, since the lower control forces give you more of an opportunity to respond and require less physical exertion. But you probably weren’t thinking much about that watching the nose pop up as you lifted off earlier.

Fly Without a Yoke

Now let’s flip it: your yoke or stick is disconnected or otherwise non-functional. The same trim system you just fought is all you have for pitch. The yoke moves the elevator through pushrods or cables. The trim drives a tab or surface through a separate jackscrew. A seized pushrod or broken control cable doesn’t take the trim with it, just as a jammed trim wheel doesn’t lock the elevator. When one fails, hopefully the other still works.

We’re being kind here: the elevator is going to fail in your current trimmed, level-flight position, so the airplane won’t immediately try to go anywhere. If the elevator jammed in a pitch up, such as during a climb, you’d have to fight a constant offset for the rest of the flight.

Side note: a truly jammed elevator could create a situation where the trim is erratic in behavior or actually works in reverse (nose down trim slowly pitches the airplane up). It depends on the kind of tailplane surfaces you have and how much motion of the elevator or stabilator remains, despite being jammed. That’s why experimenting in the air is essential.

RECONFIGURE THE SIMULATOR

Elevator: Don’t touch the yoke after takeoff
Ailerons: Don’t touch the yoke after takeoff
Rudder: Normal
Trim: Reset to hands-off
Altitude: 3000 MSL (descend back down if needed)
Heading: 180°

UN-PAUSE THE SIMULATOR

Depart KBLI normally with all controls working
Passing 500 feet put the yoke aside and control pitch using only trim and power. Make small inputs and then wait to see what happens. Control roll with only rudder.
Descend 500 feet back to 3000 feet. You might want to start retrimming before you get there.
Make a 90° turn and rollout, while maintaining altitude.
Turn 90° the other direction.
Fly back to KBLI and set up to land. Hint: Fly south of the field and line up with Runway 34 early to give yourself more time to get stabilized. If you’re using flaps, take it slow. Extend one notch at a time, retrim after each change, and let the airplane settle.
Fly the approach. Trim for airspeed, power for descent rate.
Land the airplane. You can use a touch of power to flatten your descent in the last 50 feet if you need to. Nobody’s going to judge you for a firm arrival without elevator control. If you go around, add power slowly and expect the nose to pop up.

If at any time you lose control and crash, go back to step 1 and start over.

PAUSE THE SIMULATOR AND DEBRIEF

No-yoke Debrief

Question 7: How well could you control pitch without a primary pitch control?

Controlling pitch with trim alone feels like you’re flying by suggestion: Make a change, and it’ll get there on its own time. That’s because trim changes the aerodynamic load on the elevator, which repositions in response. It means you have to think further ahead and lead your corrections.

Question 8: How did the loss of aileron and elevator affect your approach and landing?

You’ve got an airplane that flies fine but has the pitch response of a cargo ship, so energy management is even more essential. But most of the work on a well-flown approach should be done with trim and power anyway. Flap and gear extension must happen early, slowly, and one at a time, so you can compensate without losing control.

Trim authority decreases with airspeed, so the sluggishness will get worse (to the point that you may get to the stop and be out of options). You might need extra speed right into the flare. If the runway is long enough, consider skipping flaps entirely and flying a higher approach speed to remove a variable from the equation.

Roll control with the rudder is cumbersome, but certainly doable. The key is small inputs, which can be even more of a challenge in the sim than real life.

Question 9: What if you had to go around?

You likely needed full nose-up trim on approach, so applying full power to go-around would pitch the nose up sharply. That’s similar to the nose-up trim you tried, except now you don’t have your elevator to overpower it. A departure stall is a real possibility. The only way to go around would be applying power early and slowly, to keep the pitch angle under control with trim alone as the power comes in.

Wrap Up/Preparing for Next Time

This Sim Challenge opened with a simple miss: taking off with a bad trim setting. The real-world implication is that stuff like that happens. Too many accident chains get started because one simple thing cascades into big problems. The most common cause of a completely jammed control column is a forgotten control lock. That was the cause of a 2014 Gulfstream IV accident at Bedford, MA. The NTSB later found that the crew hadn’t performed flight control checks on 98% of the preceding 175 flights either.

While an “ounce of prevention” is ideal, you could still end up stuck in the air with controls that don’t work. This was a chance to experiment with using what you still have, to get back on the ground. Control failures in a home sim aren’t the same as the real thing, but it’s a head start should you ever encounter the real thing. It feels like learning to fly again, but that’s the point.

Now, taxi back to the shop and tell them they might want to take another look at whatever they did. And check that trim before you fly next time.

Extra Challenges

You can amp up this challenge by failing specific flight controls at various points. Note that each airplane in a given simulator may handle this differently (especially more customized models from third-party developers). How they handle full trim may vary as well. For example, full aft trim in a real 172 will roughly hold best glide at idle power. Full aft trim and idle power in the default 172 in X-Plane 12 will settle in at near stall speed. So, the exact performance you see here might not translate to real-world aircraft you fly. But the concepts certainly apply.

That said, you usually have three options to accomplish this, depending on your simulator platform:

Use the sim failure system. X-Plane’s Equipment Failures menu can disable individual control surfaces and create a trim runaway. MSFS 2024 does not currently have a failure creation system.
Unbind the control axis. In your controller settings, unbind the pitch axis from your yoke or stick for an elevator failure. This works in any sim.
Abide by the honor system. When a control is “failed,” just don’t touch it. You might want a sticky note or piece of tape on your yoke trim switch to remember not to touch it.

Once you have the ability to fail specific controls, you could try one of these:

Jammed elevator. Fly a traffic pattern with both elevator failed in a specific position. Trimming may have some surprising results. You could also fail both the elevator and ailerons in some inconvenient position.
Differential power in a twin. If you have a twin, try maneuvering on differential thrust alone. Left engine up for right turns, right engine up for left. Set up at 3,000’ over the bay and see if you can hold altitude and make controlled turns. Then try to bring it back to Runway 34.

Want Even More?

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