Since You Asked: To trim or not to trim
Required on steep turns?
Dear Rod:
I read where the new private pilot airman certification standards (ACS) requires private pilots to use trim in steep turns on their private pilot checkride. Several instructors say they teach the use of trim during steep turns (as does my instructor). What’s your opinion on the matter?
Erica
Greetings Erica:
First, the “use of trim in a turn” requirement is found in the Knowledge section of the ACS, not the Skills section (see page 48 of the private pilot ACS). Therefore, use of trim in a steep turn isn’t a required skill demonstration. The only time a “use of trim in a turn” skill demonstration is expected is when making level flight turns to a heading during the instrument portion of the ACS (see page 59 of the ACS). Therefore, while the ACS doesn’t require the use of trim during a steep turn, it certainly doesn’t discourage its use.
Keep in mind that trimming is always a good thing when the elevator pressure is constant and experienced for a “relatively” long duration in a “1-G” condition. For example, you should trim during a climb or descent. Trimming while turning to a heading in level flight isn’t a long-duration event, and would certainly be a workload-intensive activity. I don’t know anyone who does this when flying either by visual references or on instruments.
Trimming during a steep turn (more than a 1-G condition) diminishes the airplane’s natural stall-recovery potential. For instance, if you’re doing steep turns over a ground reference and you trim away the stick force, any distraction might make it easier for you to inadvertently enter an accelerated stall. After all, you have no sense of how much backpressure is presently being applied in the turn. You want to feel the aft stick force in a turn as a reminder of your closer proximity to a stall. Additionally, steep turns are not done for long durations. In fact, if you use a steep turn in real life, you’d typically do one for 180 degrees (think “blind-canyon turn-around”). Yes, there’s more than one way to fly an airplane, but I know of no other way to teach the relationship between elevator draw and G-loading other than doing a trim-free steep turn (no, accelerated stalls aren’t as effective in teaching this relationship).
Rod Machado is a flight instructor, author, educator, and speaker. See his CFI affiliate program online.
Related Articles
