Hello.

 

Due to whatever reason, I found that especially on higher Gross Weights, the plane starts to rotate on it´s own during T/O Run prior to reaching vR.

 

E.g.:

TOW: 378to.

Flaps 10

TOCG 22%

Thrust: TO

Stab Trim on FMC: 6.7

 

Stab Trim was set to the value on the FMC, just after passing v1, the nose begins to rise without any input on the elevators.

No noise from joystick at all, confirmed by STATUS Page on EICAS ( Elevator neutral ).

Happens regardless of RWY used and regardless of aerodrome elevation / wind / QNH /etc.

Any thoughts?

Regards,

Tom Stone

 

Edited January 27, 20197 yr by diamondstar

I've never had this happen, and I don't think I've seen this reported here either.  You are correct to identify the trim as potential problem, how are you setting up the payload?  Is this the -400 or -8?

That‘s on the -400 models, not yet tested on the -8.

Payload is setup via FMC ( FS Actions / Payload / ZFW ).

Edited January 27, 20197 yr by diamondstar

it has been reported here

 but it supposedly was solved in the latest update:

changelog  : 0007300: [General - Flight Model] 747-400 Rotates before VR with no control input (emvaos)

 

so  are you sure you have it up to date?

Yes, running version 3.00.9195.

At least on my system, that issue wasn´t fixed by the update.

OK,  I cant tell myself.  I havent seen it recently, but anyway it only happened sometimes, so this does not mean anything..