737 Trim

I was wondering what to set the 737's Trim to during takeoff and during flight and during landing. I wasn't sure if I should set to 5 during takeoff or something else.

You set it to what is right for the CG and weight of the aircraft you are flying, the take-off configuration you will be using and the limits contained in the manual?

Trim is a consequence of other things, not a constant.

Should be in the checklists someplace. Have you looked to see?

Pat☺

I haven't got it to hand, but I think the checklist says:

Trim: -- As Required.

~it depends on aircraft weight (load), flap setting, runway length, and more.

Nope, I don't fly the tubes.

But THIS PDF might give you what you need, maybe...

Pat☺

The default 737 does not have an FMC so you can't see the TAKEOFF REF page.

The trim will vary to load, CG, etc.. So there is no one trim setting for all scenarios.

But 5 would likely be a fairly close average.. Maybe a little more for a wide load.

I see from appx 4.5 all the way to around 6 just depending. I'd say most often with

a normal nearly full load, usually around 5.5-5.6 or so. ??

Kinda hard to trim as required when there is no way to find out what it should be

in the default jet. :(

Quote: '..there is no way to find out what it should be..'

Well, you know you will still NEED + pitch trim to take off and to land. During flight you let the AP Alt Hold automatically set the pitch trim.

But that might be a negative pitch trim. So when you deactivate the AP be sure to check vertical speed for clues and be ready to input some + pitch trim (which you were going to use anyway for landing). Too much is better than not enough IMO.

Chuck B

Quote: '..there is no way to find out what it should be..'

 

Well, you know you will still NEED + pitch trim to take off and to land. During flight you let the AP Alt Hold automatically set the pitch trim.

 

But that might be a negative pitch trim. So when you deactivate the AP be sure to check vertical speed for clues and be ready to input some + pitch trim (which you were going to use anyway for landing). Too much is better than not enough IMO.

Chuck B

Yep, but it's only really critical as far as the takeoff. Landing, you will know by feel

alone if the trim is right or not, same as any other plane. So no worries on landing.

I never set a certain "landing trim setting" before landing.

But takeoff is a bit different. The trim is more critical on takeoff due to having no

way to feel if it's right or not. And it needs to be fairly close if one is going to engage

the A/P soon after takeoff. You might, or you might not.. Just depends how you are

flying. But say you are going to go to LNAV/VNAV soon after takeoff.. You can legally

engage at 400 ft AGL. The trim has to be right or else you won't be able to release

pressure from the yoke. You can't engage the A/P if there is yoke pressure. I guess

you could trim it out before you engage, but that's not really the way you want to do it.

You want to be properly trimmed on the initial climb out so you can just release pressure

on the yoke and engage in a quick one-two motion. And if hand flying it out, no massive

trim changes will be required on the climb out.