What a CFI Wants You to Know: Trimming the Aircraft Properly

Instead, keep one hand on the yoke or stick, and the other on the throttle during takeoff just in case you have to abort—like when that deer runs onto the runway or goodness forbid, there's another aircraft, or a car or something else on the runway and you are heading towards it. Get that power to idle and stop.

If there is sufficient runway (you did check performance numbers as part of the preflight, didn't you?), you shouldn't need a violent application of back pressure to get a light airplane into the air. When the proper airspeed is obtained, when there is enough airflow over the wings of the airplane, a little bit of back pressure will allow the airplane to fly off the runway. Don't believe me? Try this in an AATD: Put in two turns of nose up trim—in lieu of back pressure here—then apply full power and fold your arms on your chest. Steer with the rudder pedals. When there's sufficient airflow over the wings resulting in sufficient airspeed, lift overcomes the weight and drag—and up you go without touching the yoke or stick.

You also don't need to hold on to the yoke or stick with the grip of a linebacker. Your grip on the stick or yoke is not what is keeping the aircraft in the air—but it can lead to over-controlling. Instead, hold it like it is a coffee mug handle, or the hand of a child. Seriously, sometimes I find myself flying with my pinky sticking up—that debutante training stays with you—just to demonstrate the gentle touch to a learner.

Landings can get very exciting when the learner uses two hands and yanks the airplane into the nose-up attitude during touchdown. I witnessed this for the first time as a 10-hour CFI. I was flying with a woman who was having trouble learning to land. I was the latest in a string of CFIs. She told me she pulled on the yoke hard because she didn’t feel she was strong—after the over-controlling and subsequent bounce led to my very first "my airplane!" call, I disagreed. The real issue was that she wasn't using the trim to relieve control pressures. Instead, she was jerking the yoke back with both hands as the aircraft approached the runway. Once she learned how to apply trim, her flying became much smoother and her landings became landings and not gravity checks with excessive force.

“Pitch, power, trim” is a mantra for keeping your aircraft under control. When you adjust the pitch or power, verify the aircraft is in trim. This can be done by relaxing your hand on the yoke or stick, and noticing if the aircraft climbs, descends, or stays level. This technique of “letting the airplane talk to you” is much simpler than trying to figure out how many turns of the trim wheel you need to apply. And please don't be in a hurry to apply trim—one twist or two—see how the aircraft reacts for a few seconds, then adjust if needed.

You can trim for attitude, or you can trim for airspeed. You may benefit from going out to the practice area, going up to an appropriate altitude and experimenting with this. Note the specific power settings and pitch settings that create a descent at 500 fpm.

When it comes to landings, with a little practice, you will quickly figure out how much trim you need to hold attitude and airspeed—and every airplane, even the same makes and models, will be a little different. The weight of the aircraft on a given day impacts this as well. Remember this when you take passengers with you. The aircraft, when fully or even partially loaded beyond the usual “just you” or “just you and the instructor” will behave differently. Again, let the airplane “talk” to you, and adjust the pitch, power, and trim until the airplane does what you want it to. Be very careful the first time you carry a passenger or cargo in the backseat. Anticipate the need for nose-down trim.

Is “trim check” on the preflight walkaround inspection checklist for your airplane? This check should be more than making sure that the hinge that actuates the trim tab is in good condition. Note the position of the tab—and here's the important part—compare it to any “trim set for takeoff” placard or notation near the trim wheel or indicator. Sometimes, the neutral position of the tab does not align with the notation that indicates the proper takeoff trim position.

It happened to a newly minted CFI I was working with—he was tasked with flying a new-to-us Cessna 172 from its former home to our airport. When he landed, he said he was a little rattled because on takeoff it had pitched up so much that he had to use forward pressure to avoid a stall—despite the fact he set the trim to the indicated “takeoff” position before adding power. 

The mechanics went through the airplane and didn't find any issues, so it was agreed I would be the test pilot. I invited the newly minted CFI to come along.

In the cockpit during the before takeoff checklist, I adjusted the trim wheel to the “takeoff” position per the placard, then I brought the yoke all the way back and looked over my shoulder at the tail. The trim tab should have been flush with the tail—but it wasn't, not by a long shot. 

Keeping my eye on the tab, I adjusted the wheel until the tab was flush. "Trim set for takeoff" by reference to the tail was significantly different from the position of the takeoff placard. 

"There's your problem," I chuckled, remembering the words of my very experienced CFI from many moons ago—he taught me to always look over my shoulder out the window at the tail to visually confirm the position of the trim tab before I added power. I can still hear his voice telling me "the back window is a luxury—use it!" 

So what do you do if the aircraft lacks a back window? Set the trim to neutral when you’re in the cockpit during the preflight inspection and then check it during your walkaround.

Teachable moment: When handing over the controls to another pilot in a non-emergency situation, make sure it is trimmed for stable flight. Trim is not really about pilot personal preference like setting the seat position in a car—it's about the airplane's attitude. When an aircraft is hard to fly, it is often because it is improperly trimmed. 

Some aircraft are harder to trim than others—going from a design that has a crank on the ceiling to one with a vertical wheel in the center console often comes with a learning curve. There are also some aircraft that require you to carry ballast in the baggage compartment, such as tailwheel aircraft and light twins, in addition to applying trim.

Some pilots can get creative. I flew with a client who owned a 1950s-era Cessna 172 with manual flaps. I was a fill-in CFI—the client usually flew with someone else.

The client said the aircraft was hard to land, in particular to flare, so they had placed a few bags of sand in the baggage compartment. This was the first time I had heard of this for a tricycle-gear airplane.

Out came the aircraft's weight-and-balance sheet and the aircraft flight manual—brittle and yellow with age. We double-checked the information on the weight and balance and the center of gravity limits. Nothing jumped out. We crunched the numbers twice. We were neither overweight or out of CG.

"Do you run out of trim during landing?" I asked.

"Run out of what?" 

I pointed at the trim wheel. 

Learning took place.

The learner had been wondering what that round thing did in the airplane.