737 roll with flap down

[rr892igw]

I flew an A/C two days back,the a/c roll left
after liftoff just like no.1 engine failed.I
had 2 units of R aileron to keep it level.After cleaning up,it was neutral.It was again about 2.5 R wing down to keep wings
level on approach.Nil flap/slat split observed.
Anyone had the same experience before?

Boeing's redundency + Airbus fly-by-wire
= THE PERFECT AIRPLANEnull :cool:

[static]

Every now and then you find a 737 with this problem, typically just after maintenance.
It`s probably just a case of sloppy flap adjustment. You should write it up though.

[avmech]

Likely a flap rig problem or possibly broken toggles. In any case, it should be investigated immediately and corrected. Another possibility is fuel quantity error, but less likely.

[Jambo Buana]

Lateral trim drag is one of the biggest problems with the 737NG. If you were flying one of these new variants it could be caused by any of the following:-

1).Rigging as mentioned earlier.

2).Where the trailing edge flap meets the fuselge there is a rubber strip. Airflow sometimes breaks through on one side earlier than the other and causes a flow that sticks to the fuselage on one side aft of the flap, whilst a little broken on the other. This causes a sideways moment resulting in a yaw that is normally picked up with aileron. You'd be amazed at what a little rubber strip can change aerodynamically. Also the abrupt closure of this gap can cause the same effect. If you are on approach say and you ask for flap 40 from the flap 15 setting (allowable now with the NG) the rate of closure that the gap between fuselage and flap is made can cause the same effect. I think thats why some pilots control there own rate with flap 30 and 40. You know the guys who move the lever slowly!

3).Also in the wheel well if you look aft and outboard there is a flap which is designed to open at larger flap settings and higher AoA's to allow dynamic airflow into the well to be exhausted. Sometimes these flaps need a lube job to allow simultaneous opening otherwise dynamic airflow causes pressure buildup in the wheel wells and this may cause some lateral control anomalies.
Hope this gives some insight.

[spannerhead]

Sounds to me like aftflap rigging.
You probably won't get the opportunity, but if you do, extend the flaps and measure from the trailing edge of the mid flap to the trailing edge of the aft flap (at the outboard end of the outboard flaps). Compare both sides and I bet there is a difference.
The R/H dimension will be more than the L/H.