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For some reason I ended up binge watching E-2s and C-2s doing shots and traps on YT. One thing caught my eye; especially during the approach, the pilot’s left thumb is in constant motion pressing a control on the yolk.

One imagines the radio PTT, but there seems to be no relationship between the clicks and talking during the times where both are visible, and it’s not like they are push-n-holding, it’s click click click!

So then one starts thinking about trim, but what madman designs a plane that requires so many trim adjustments during landing, and then requires a separate push for each adjustment?

Anyone know what’s going on? Here’s an example:

UPDATE: here's another example:

Look around 0:55 and again at 1:25 - his thumb is positively dancing. I can see in this video it is a hat, so I guess it is trim.

Never having flown anything larger than a s-twotter, what is going on here? I'm used to adjusting trim maybe one or two times in the circuit, this is nuts.

P.s. why the heck is there a privacy screen on the door?

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  • $\begingroup$ Possibly related to the "direct lift control" system? $\endgroup$
    – quiet flyer
    Commented Jan 16, 2021 at 13:53
  • $\begingroup$ The "privacy screen" is probably more about blocking light during night flying. $\endgroup$
    – Ralph J ♦
    Commented Jan 16, 2021 at 15:38
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    $\begingroup$ Don't see what you're referring to in that video, but it's almost certainly elevator trim. $\endgroup$
    – Ralph J ♦
    Commented Jan 16, 2021 at 15:43
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    $\begingroup$ Yeah, you didn't pick a good example video. And I agree with Ralph, probably trimming... $\endgroup$
    – Michael Hall
    Commented Jan 16, 2021 at 18:07
  • $\begingroup$ It would be good to find out how the direct lift control system is controlled on this aircraft and find out whether or not the thumb button has anything to do with it. $\endgroup$
    – quiet flyer
    Commented Jan 17, 2021 at 1:14

3 Answers 3

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Most likely the pilot is trimming the airplane to alleviate control pressures after he adjusts his airspeed in the pattern. Ideally you want to trim out any kind of control pressure that you have to place on the yoke, or rudder pedals, first adjusting your speed as desired using the power levers, then trimming using elevator-rudder-aileron trimming procedure. The “coolie hat” switch on the left grip on the yoke provides both elevator and aileron trim.

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Privacy screen is on the D.. and it's for light discipline in the back of the plane for the operators. There are three people sitting back there with very little light while the systems are in operation, when landing, or taking off the operators are sitting facing forward, lights on, most systems are off.

There are other reasons in the past, for C and earlier models that don't really apply to the D.

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  • $\begingroup$ "it's for light discipline in the back of the plane" - ahhh, yes. $\endgroup$
    – Maury Markowitz
    Commented Nov 5, 2023 at 19:38
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The left coolie hat provides elevator and rudder trim. Coming into the break at 250 KIAS (or greater), there is quite a bit of deceleration to get to “on speed.” Typically this would require quite a bit of nose up trim inputs. The rudder input would vary based on the idle power setting (in the break), slowing down, and adding power back on (to catch “on speed”).

As an example, I would roll into final with a slightly fast speed, then click 2 times for nose up trim while pulling power / doing the wings level transition into the groove. This would keep the plane on speed as I added power back on the aircraft to maintain the glideslope.

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