AN A300 CREW RPTS AN UNCOMMANDED R ROLL AFTER TKOF POSSIBLY DUE TO CONTAMINATED SURFACES. THE ACFT HAD BEEN DE-ICED PRIOR TO TKOF BUT WAS PREVIOUSLY PARKED IN ICE AND SNOW AN ENTIRE WEEKEND.

Narrative

DURING PREFLT THE CAPT REQUESTED A SECOND DE-ICING DUE TO THE FACT THAT THE DE-ICING CREW DID NOT LEAVE THE TYPE OF FLUID NOR THE HOLDOVER START TIME WITH THE OPERATING CREW. HEAVY SNOW AND SLEET DEVELOPED AFTER THE FIRST DE-ICING. BOTH THE FO AND MYSELF VERIFIED AND CONFIRMED THE RNAV SID IN THE FMC DURING COCKPIT PREFLT DUTIES. DURING DEP FROM ZZZZ ON THE RNAV SID AT APPROX 3000 FT THE AUTOPLT SUDDENLY TURNED THE ACFT SLIGHTLY TO THE R OF COURSE MOMENTARILY OFF THE SID. THE FO WAS THE PF. THE FO INTERVENED BY CLICKING OFF THE AUTOPLT AND FLEW THE ACFT BACK ONTO THE SID. THE ACFT HAD BEEN PARKED IN ZZZZ ALL WEEKEND AND SLEET; ICE AND SNOW HAD DEVELOPED ON THE SURFACES. THE SUDDEN ROLL EXPERIENCED WAS THAT SIMILAR TO AN APCH ROLL OSCILLATION WHEN ICE DEVELOPS ON THE CTL SURFACES DURING AN APCH. WE ASKED ATC AFTER THE EVENT HAD WE DEVIATED FROM COURSE AND HE ANSWERED NO. THERE WERE NO FURTHER ENCOUNTERS WITH THE AUTOPLT FOR THE REST OF THE FLT.SUPPLEMENTAL INFO FROM ACN 813201: THE FLT CTL CHECK RESPONDED AS IT SHOULD HAVE AND THE AIRPLANE BEHAVED NORMALLY ON THE TAKEOFF ROLL AND INITIAL CLIMB. AT 1000 FT THE AUTOPLT WAS SELECTED ON IN ACCORDANCE WITH DEP PROCS. WHEN THE ACFT WAS APCHING ITS FIRST TURN TO THE L; IT DEPARTED THE COURSE AND STARTED AN UNCOMMANDED R TURN.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THAT ICE ACCUMULATION ON FLT CTL SURFACES DURING APCH IS A KNOWN ISSUE WITH THIS ACFT. HIS COMPANY HAS DEVELOPED A PROC THAT TELLS THE CREW TO DISCONNECT THE AUTOPLT AND HAND FLY THE APCH. IN THIS EVENT; THE RPTR IS SPECULATING THAT ICE WAS THE ISSUE AND SO THE APCH PROCEDURES WERE APPLIED. HE DOESN'T KNOW WHAT CAUSED THE UNCOMMANDED ROLL BUT BECAUSE IT FELT SIMILAR TO THE APCH ROLL HE IS SPECULATING THAT WAS CAUSED BY ICING.