hi,i'm a bit a noob on 737ng

i was landing on rwy 29L OISS,ILS CAT I ,then i realised that after A/P disengaging on final,ngx will flare-automaticly- about 100' AGL

i checked the AP,was completely disengaged

is that normal?if i want AP not to do this,what i'm supposed to do?or where did i go wrong?

p.s. i was flying with 737-800 Boeing livery, in a LAND2 approach with honeywell MCP

Regards

Could you please post some screen shots of the cockpit panels?

 

Maybe you are inadvertently adjusting the throttles or trim (unintentional adjusting of hardware controllers)?

 

Perhaps it is also partly ground effect?

Unfortunately,i cant post a pic till 3 weeks later(sorry),but im pretty sure that autopilot was disengaged,trim wasnt moving,A/T was disengaged,and controls were neutral,i tried it in another way in ILS6 OIIE,29R.a bit same conditions and i gave this sinister automatic trim up,wierd!

Search the forum/the FCOM for "speed trim" and all will be explained to you ;-)

 

So long,

 

Oli

 

 

Oliver Branaschky

Thank you oliver,realy helpful

But my speed was constant and it was about 146,maybe - 1 knot,and i was descending 400 fpm,so why speed trim came in and took trim control?and is there any way to shut it off for landing?

Thank you oliver,realy helpful

But my speed was constant and it was about 146,maybe - 1 knot,and i was descending 400 fpm,so why speed trim came in and took trim control?and is there any way to shut it off for landing?

Speed Trim isn't active on approach and landing. It's more for takeoff and go-around.

 

Nothing in the system would do as you're describing. So, make sure what you're describing is actually happening. Why do you say it was a trim issue? Did you see the trim wheel moving on it's own?

I'm pretty sure tham trim wheel was moving like ap is engaged or something like this

Never had this problem before.i'm not very familiar with boeing,so plz speak airbusy!when speed trim iterupts?how it operates?and what is that trim immediate change reason?

 

I'm pretty sure that trim wheel was moving like ap is engaged or something like thisNever had this problem before.i'm not very familiar with boeing,so plz speak airbusy!when speed trim iterupts?how it operates?and what is that trim immediate change reason?

Speed trim isn't active on approach and landing. It's more for takeoff and go-around.

 

Nothing in the system would do as you're describing. So, make sure what you're describing is actually happening. Why do you say it was a trim issue? Did you see the trim wheel moving on it's own?

 

Hm, I'm pretty sure that I read somewhere in the documentation or maybe in this forum that during approach, if the STS senses trim requirement and there has been no trim input by the pilots for x seconds, the speed trim will trim the aircraft. Since I can't find it, though, and Matt sure knows his job, I figure I was wrong ;-)

As Oliver suggested, check out the FCOM section on Flight Controls.

 

I'm not an Airbus guy, so I can't help with any analogies.

 

When you say the jet "flared automatically," why do you say that? You say you were in "LAND 2," when did you disengage the A/P? Was it after 400ft? Maybe it was the "pre-trim" for the autoland.

 

Matt sure knows his job, I figure I was wrong ;-)

Don't be so sure! I've been on vacation for the last 3 weeks and I'm not sure I can tell the front end from the back end now.

Don't be so sure! I've been on vacation for the last 3 weeks and I'm not sure I can tell the front end from the back end now.

 

But still... the FCOM agrees with you ;-)

When AP is Off, is off, the speed trim avaiable only at low altitude, low speed, will only "unload" the control column by adding trim in the column direction if it is hold for some seconds.

BAsically, if you're flying in the "speed trim" conditions and you are pulling the column to mantain your aircraft attitude, the trim will give nose up command and you will slowly release the column. It is designed to remove workload,

It will never flare the plane. Probably in your case it was a coincidence. Check on the next flight

Alright,i'll check it next flight,and i'll post a video of it,thanks for your kind replys