Narrative:

As I rotated the aircraft and lifted off the aircraft started a roll to the right. I immediately corrected and kept wings level. I initially thought I had lost an engine as the roll was consistent with an engine loss but I did not have any adverse yaw. I checked engines and they were normal. I had no problem with controling the roll but it required about 5-6 units of left wing down aileron input to maintain wings level. At no time during this entire flight was there a problem with maintaining wings level so long as we maintained 5-6 units of left aileron trim. As we climbed out; the first officer and I were analyzing the situation. The aircraft would trim out fine and could be flown 'hands off' with the 5-6 units of left wing down aileron yoke displacement. I did not use autoplt. We referred to the QRH and used the rudder uncommanded yaw/roll checklist (this is for the rudder but was the closest checklist that pertained to this problem). We accomplished the items but nothing changed. All circuit breaker's were in. We checked for fuel imbalance; but gauges checked good and read even. Hydraulic pressures and quantities were normal. Flaps were up and led lights were out. All indications in the cockpit were normal. I called the flight attendants asked them to look at the wing and to tell me what they saw. They reported the left wing spoilers were up slightly (3-6 inches) and the right wing was normal. We observed the left aileron was slightly up and the right one also seemed slightly up. Left wing was consistent with the control column input; while the right wing was neither normal nor consistent with out input. We initiated contact with dispatch and had maintenance control on the call. We advised them as to our situation and asked for any suggestions. We had already accomplished their suggestions and maintenance duty told us they would have maintenance meet us in ZZZ. I requested dispatch bring up the chief pilot on duty. I advised him of our situation and suggested we divert to ZZZ1 (the closest field at this time). He concurred and the flight was diverted. We declared an emergency with ATC. I informed the passenger of our situation telling them we were going to land in ZZZ1 as a precaution. I told the flight attendants to secure the cabin for a normal landing and told them not to prepare the cabin. I did not tell the passenger I had declared an emergency. We descended into ZZZ1. We slowed the aircraft slowly to ensure we had no controllability problems. We configured early and slowly configured; stabilizing the aircraft at each flap setting. We flew a wide visual approach with ILS backup. I flew a slightly fast final (+10 or so) as the aircraft was very stable at that speed. We landed normally. After we cleared the runway we canceled the emergency. After shutdown; maintenance told us a control cable had broken.callback conversation with reporter revealed the following information: reporter stated that the aircraft's controllability was never in question; adding that the aircraft was a little slower turning than with both ailerons but safety of flight was not in question. On the ground reporter could see a control cable hanging loose and was told by maintenance that it was the right aileron control cable.

Related reports:

Google
 

Original NASA ASRS Text

Title: THE RIGHT AILERON CTL CABLE ON A B737-300 BECAME DISCONNECTED; REQUIRING 5-6 AILERON TRIM UNITS TO MAINTAIN WINGS LEVEL. AN EMER WAS DECLARED WITH A DIVERSION.

Narrative: AS I ROTATED THE ACFT AND LIFTED OFF THE ACFT STARTED A ROLL TO THE RIGHT. I IMMEDIATELY CORRECTED AND KEPT WINGS LEVEL. I INITIALLY THOUGHT I HAD LOST AN ENG AS THE ROLL WAS CONSISTENT WITH AN ENG LOSS BUT I DID NOT HAVE ANY ADVERSE YAW. I CHKED ENGS AND THEY WERE NORMAL. I HAD NO PROB WITH CTLING THE ROLL BUT IT REQUIRED ABOUT 5-6 UNITS OF L WING DOWN AILERON INPUT TO MAINTAIN WINGS LEVEL. AT NO TIME DURING THIS ENTIRE FLT WAS THERE A PROBLEM WITH MAINTAINING WINGS LEVEL SO LONG AS WE MAINTAINED 5-6 UNITS OF LEFT AILERON TRIM. AS WE CLBED OUT; THE FO AND I WERE ANALYZING THE SITUATION. THE ACFT WOULD TRIM OUT FINE AND COULD BE FLOWN 'HANDS OFF' WITH THE 5-6 UNITS OF LEFT WING DOWN AILERON YOKE DISPLACEMENT. I DID NOT USE AUTOPLT. WE REFERRED TO THE QRH AND USED THE RUDDER UNCOMMANDED YAW/ROLL CHKLIST (THIS IS FOR THE RUDDER BUT WAS THE CLOSEST CHKLIST THAT PERTAINED TO THIS PROBLEM). WE ACCOMPLISHED THE ITEMS BUT NOTHING CHANGED. ALL CB'S WERE IN. WE CHKED FOR FUEL IMBALANCE; BUT GAUGES CHKED GOOD AND READ EVEN. HYD PRESSURES AND QUANTITIES WERE NORMAL. FLAPS WERE UP AND LED LIGHTS WERE OUT. ALL INDICATIONS IN THE COCKPIT WERE NORMAL. I CALLED THE FLT ATTENDANTS ASKED THEM TO LOOK AT THE WING AND TO TELL ME WHAT THEY SAW. THEY RPTED THE LEFT WING SPOILERS WERE UP SLIGHTLY (3-6 INCHES) AND THE RIGHT WING WAS NORMAL. WE OBSERVED THE LEFT AILERON WAS SLIGHTLY UP AND THE RIGHT ONE ALSO SEEMED SLIGHTLY UP. LEFT WING WAS CONSISTENT WITH THE CTL COLUMN INPUT; WHILE THE RIGHT WING WAS NEITHER NORMAL NOR CONSISTENT WITH OUT INPUT. WE INITIATED CONTACT WITH DISPATCH AND HAD MAINT CTL ON THE CALL. WE ADVISED THEM AS TO OUR SITUATION AND ASKED FOR ANY SUGGESTIONS. WE HAD ALREADY ACCOMPLISHED THEIR SUGGESTIONS AND MAINT DUTY TOLD US THEY WOULD HAVE MAINT MEET US IN ZZZ. I REQUESTED DISPATCH BRING UP THE CHIEF PLT ON DUTY. I ADVISED HIM OF OUR SITUATION AND SUGGESTED WE DIVERT TO ZZZ1 (THE CLOSEST FIELD AT THIS TIME). HE CONCURRED AND THE FLT WAS DIVERTED. WE DECLARED AN EMER WITH ATC. I INFORMED THE PAX OF OUR SITUATION TELLING THEM WE WERE GOING TO LAND IN ZZZ1 AS A PRECAUTION. I TOLD THE FLT ATTENDANTS TO SECURE THE CABIN FOR A NORMAL LNDG AND TOLD THEM NOT TO PREPARE THE CABIN. I DID NOT TELL THE PAX I HAD DECLARED AN EMER. WE DSNDED INTO ZZZ1. WE SLOWED THE ACFT SLOWLY TO ENSURE WE HAD NO CONTROLLABILITY PROBLEMS. WE CONFIGURED EARLY AND SLOWLY CONFIGURED; STABILIZING THE ACFT AT EACH FLAP SETTING. WE FLEW A WIDE VISUAL APCH WITH ILS BACKUP. I FLEW A SLIGHTLY FAST FINAL (+10 OR SO) AS THE ACFT WAS VERY STABLE AT THAT SPD. WE LANDED NORMALLY. AFTER WE CLRED THE RWY WE CANCELED THE EMER. AFTER SHUTDOWN; MAINT TOLD US A CTL CABLE HAD BROKEN.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT THE ACFT'S CONTROLLABILITY WAS NEVER IN QUESTION; ADDING THAT THE ACFT WAS A LITTLE SLOWER TURNING THAN WITH BOTH AILERONS BUT SAFETY OF FLT WAS NOT IN QUESTION. ON THE GND RPTR COULD SEE A CTL CABLE HANGING LOOSE AND WAS TOLD BY MAINT THAT IT WAS THE RIGHT AILERON CTL CABLE.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.