SF340 flight crew on repositioning flight with autoplt engaged experience autotrim malfunction.

Attributes
ACN	687358
Time
Date	200602
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	msl single value : 10000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : zzz.tracon
Operator	common carrier : air carrier
Make Model Name	SF 340B
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Experience	flight time last 90 days : 100 flight time total : 3350 flight time type : 475
ASRS Report	687358
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	aircraft equipment problem : less severe
Independent Detector	other flight crewa
Resolutory Action	flight crew : overrode automation other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

After arriving in ZZZ and after a brief discussion on the status of the aircraft with the mechanics on duty; and accomplishing all of the first flight of the day duties required for the first officer; we then departed for ZZZ. After leveling off at 10000 ft about 25 NM south of ZZZ; the captain engaged the autoplt which then disconnected along with an automatic trim master warning on the control wheel panel. The captain continued to hand fly the aircraft and called for the appropriate checklist. He attempted to trim up the roll and realized that the primary roll trim was working opposite than normal. We made the decision to return to ZZZ and requested to do so with ATC. At no time did we declare an emergency. We landed safely at ZZZ with no incident.

Original NASA ASRS Text

Title: SF340 FLT CREW ON REPOSITIONING FLT WITH AUTOPLT ENGAGED EXPERIENCE AUTOTRIM MALFUNCTION.

Narrative: AFTER ARRIVING IN ZZZ AND AFTER A BRIEF DISCUSSION ON THE STATUS OF THE ACFT WITH THE MECHS ON DUTY; AND ACCOMPLISHING ALL OF THE FIRST FLT OF THE DAY DUTIES REQUIRED FOR THE FO; WE THEN DEPARTED FOR ZZZ. AFTER LEVELING OFF AT 10000 FT ABOUT 25 NM S OF ZZZ; THE CAPT ENGAGED THE AUTOPLT WHICH THEN DISCONNECTED ALONG WITH AN AUTO TRIM MASTER WARNING ON THE CTL WHEEL PANEL. THE CAPT CONTINUED TO HAND FLY THE ACFT AND CALLED FOR THE APPROPRIATE CHKLIST. HE ATTEMPTED TO TRIM UP THE ROLL AND REALIZED THAT THE PRIMARY ROLL TRIM WAS WORKING OPPOSITE THAN NORMAL. WE MADE THE DECISION TO RETURN TO ZZZ AND REQUESTED TO DO SO WITH ATC. AT NO TIME DID WE DECLARE AN EMER. WE LANDED SAFELY AT ZZZ WITH NO INCIDENT.

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.