Is the problem in the pilot or in the A/P?

So when i put vs a/p on it pulls the nose radically up or down. Why?

this is known issue on A321 and 777 300ER I guess…

1 Like

Because you don’t have the plane trimmed properly. Eliminate the purple in the trim box prior to engaging. Soley pilot error.

4 Likes

All planes that i have flyed

ok… but personally only have issue on A321 and 777 300ER
and it’s confirmed

1 Like

To answer the question. Pilot.

When you turn on AP, you naeed to make sure the the aircraft is trimmed. Most plots see this after taking off and are climbing at +3000 VS and then turn on AP the nose will pitch down violently.

Now if you are saying that at cruise altitude your nose moves up and down, that is a known issue. Compound that with being overweight and/or high/low speed and it can make it worse.

4 Likes

That’s a first not sure why you would need the vector indicator near the horizoon bar to get a smooth A/P engagement. Since that only happens at higher speed.

Sorry I adjusted my comment. It plays into it but is more of a symptom of not being trimmed like you said.

3 Likes

is there any app thing to say how much trim is needed?

I already told you it’s a feel not a calculation.

1 Like

but you can’t get the trim right on ground if don’t do some mystical calculations

1 Like

You don’t need to get it right on the ground. you perfect it in the air. I start out with 15% on most aircraft. Except the spit which I do -15% and the MD which is closer to 50-60%.

1 Like

Keep in mind, aircraft load % plays a factor in how much trim is/will be needed.

1 Like

I have fiund it is around 23% for the B777s as that is what you would need to adjust it to that at cruise if you kept it at 15% on climb

1 Like

yea i know thats why i was thinking that there could be some calculator that calculates the trim when weight is … and plane is … so you need …% trim

1 Like

MD-11’s as well I usually have to adjust ap twice.

oh yeah? I have flew them quite many times…
Haven’t experienced yet…Thanks for report tho

It’s all I fly now. I used to change it up, but whether it’s the commercial version or freighter I simply just no longer find much interest in flying anything else. I know our beloved if provides a multitude of liveries and models but I have found that as certainly proves true in real life no takeoff, route, pattern, approach, or landings can ever be routine, the same. I can wheel the 11 like a fighter when I am truly just having fun or like the behometh freight mover and passenger carrier she was designed and built to be. God I’m all giddy just talking about it!!!

3 Likes

i have the same problem :D @Douglas_Chanley

Here’s a basic guide for using elevator trim

1 Like