Continuing Ed

To trim, or not, in the flare

I regularly fly with five different pilots, so I get lots of opportunities to see how different pilots use different techniques to accomplish the same objective. Of course, being typical pilots, which means my-way-or-the-highway stubborn, each assumes that his is absolutely, positively the only technique that works and should be used. Of course, each is incorrect in making such an assumption. A technique is, by definition, a method or way of accomplishing a task. Just as there are many methods or ways of, say, performing a beautiful piece of music, so too are there many methods and ways of making an airplane do what needs to be done.

Take landings, for example. The basic objective is simple enough: a smooth, main-wheels-only touchdown, in the touchdown zone, at minimum forward speed. How we get there is a little more complicated, involving numerous small steps and pilot actions. As the airplane crosses over the airport boundary and descends to the runway, reduce power to idle (if you haven't done so already) and arrest the sink rate with a bit of back-pressure on the yoke or stick.

Then, using various sensory and physical cues, finesse the sink rate so that the main wheels touch the runway at the moment the wing stalls. As the airplane slows, gently relax back-pressure on the yoke until the nosewheel touches. Finally, apply brakes to slow to taxi speed before turning off the runway.

That's a great landing--comfortably smooth to pilot and passengers, with the touchdown occurring at the proper point on the runway at the slowest possible forward and vertical speeds. At the moment of touchdown the fragile nosewheel is still a few safe inches above the runway in no danger of a jarring impact.

The point is, there is no single incontrovertible set of procedures to follow to achieve that great landing. Instead, there are many ways or methods--many techniques--that will produce the desired result. Each of us calls on our instruction, observations, experimentation, and experience to assemble our own set of techniques.

One of the interesting approach and landing techniques I've observed while flying with different pilots is use of trim in the final moments of the flight. Among those pilots--me included--there appear to be three basic methods of using trim on landing. The first is to apply nose-up trim more or less constantly just before and during the flare. The nose pitches up as the airplane flares and slows, resulting in a nice main-wheels-only touchdown.

The second technique is to apply a moderate amount of nose-up trim in the flare. The extra trim helps reduce control force, but you still have to pull back on the yoke a bit to make a main-wheels-only touchdown.

The third trim-on-landing technique is to ignore the trim setting in the final moments of the landing. Land with what you had set in the final approach. Obviously, this technique requires the most pitch-control input by the pilot in the final moments of the flare and touchdown.

Each of the three techniques has its pros and cons. Constantly trimming through the flare has the advantage of producing an autopilot-like automatic increase in nose-up pitch attitude as the airplane flares, slows, and sinks to the runway. It lessens the effort required of the pilot to control pitch using the yoke, and minimizes the potential for a three-point touchdown or, worse, a nosewheel-first arrival. Done correctly, it results in a beautifully smooth transition from final approach to the flare and subsequent touchdown.

The disadvantage is that the technique requires intimate familiarity with the airplane, in particular how it responds to trim inputs. Constant trimming in one airplane may produce more of a pitching response than in another. Thus, the technique is not easily transferable from one airplane to the next unless you are very familiar with both.

The bigger concern with the constant-trimming method is the potential for a sudden and strong pitch-up in the event of a go-around. With the pitch trim tab in, or very nearly in, the full nose-up position just prior to touchdown, a sudden application of full power will strongly pitch the nose up, requiring an equally strong opposing force on the yoke to avoid a power-on stall.

Using a moderate amount of trim in the flare reduces the potential for a strong nose-up pitch change on a full-power go-around, but it also means the pilot has to manipulate the yoke with more finesse to make a smooth main-wheels-first touchdown.

The third method--leave the trim where it was set for the final approach--removes any concern about a go-around. Pitch attitude should be easy to control using the yoke, although it will take more feel and input than using constant or moderate trim. It also is a technique that can be used with almost every airplane. (A caveat: Some airplanes can become nose-heavy if no additional nose-up trim is added in the flare. If you're flying an airplane that you're not familiar with, be sensitive to the need for trim, and don't hesitate to use it.)

I'm a member of the third camp--no trimming in the flare. I can't explain why I chose that method or when, but that's the way I land. To be honest, I don't think it's the best method to use in every airplane. I used to be a partner in a Piper Twin Comanche, which I found especially difficult to land on the mains only. On the other hand, my partner trimmed throughout the flare (the trim indicator would be in the full nose-up position after landing), and he made more smooth, main-wheels touchdowns than me. However, of the three airplanes I now fly regularly, I find the no-trim technique works just fine with each.

So, which is the better technique to use in the final moments of the flight when everyone aboard, including the pilot, is totally focused on the quality of the impending touchdown? Is it to trim constantly so that the nose comes up more or less by itself, requiring little or no manipulation of the yoke by the pilot? Is it to add a dash of nose-up trim in the flare to assist in raising the nose to the proper touchdown attitude? Or, is it to leave the trim where it was on final approach and finesse the nose attitude using the yoke only?

The answer is the same as for any pilot technique: The best method is the one that works best for you.

Mark Twombly is a writer and editor who has been flying since 1968. He is a commercial pilot with instrument and multiengine ratings and co-owner of a Piper Aztec.