Narrative:

While climbing from runway 33, the first officer noticed torque rise on left engine and pulled back left power lever to correct. When it kept slowly rising, we noticed the left propeller less than 1700 RPM (maximum). There was no adverse yaw and no out of sync sounds from propellers. We told ATC we wanted to enter downwind to return to airport and told flight attendant to brief the people for landing due to an indication problem. On base to final turn, we noticed the left blue beta light and the left green reverse lights on. The propeller gauge read about 900 RPM or so. Still, there was no adverse yaw at all. After landing, we turned off the runway and ran after landing checks and I saw 395 RPM on left propeller gauge and looked outside to confirm it was in flux and it was. Due to the lack of ctlability problems and the conflicting indications of the gauges and the beta and reverse lights, we thought that there was some kind of indication problems and therefore did not declare an emergency. The engine was not shut down due to the fact that without yaw, the engine seemed to be producing thrust and I didn't want to possibly aggravate the current problem by changing the confign of the left engine. Thinking back, I suppose we could have declared an emergency but in our haste to evaluate the situation and enter downwind for landing and checklists and advising flight attendants and the lack of any indication as far as the control of the aircraft, we decided no need for the declaration.

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Original NASA ASRS Text

Title: RPTR CITES A MISDIAGNOSIS OF ACFT EQUIP PROB MALFUNCTION AS REASON FOR NOT DECLARING AN EMER IN A RETURN LAND SIT.

Narrative: WHILE CLBING FROM RWY 33, THE FO NOTICED TORQUE RISE ON L ENG AND PULLED BACK L PWR LEVER TO CORRECT. WHEN IT KEPT SLOWLY RISING, WE NOTICED THE L PROP LESS THAN 1700 RPM (MAX). THERE WAS NO ADVERSE YAW AND NO OUT OF SYNC SOUNDS FROM PROPS. WE TOLD ATC WE WANTED TO ENTER DOWNWIND TO RETURN TO ARPT AND TOLD FLT ATTENDANT TO BRIEF THE PEOPLE FOR LNDG DUE TO AN INDICATION PROB. ON BASE TO FINAL TURN, WE NOTICED THE L BLUE BETA LIGHT AND THE L GREEN REVERSE LIGHTS ON. THE PROP GAUGE READ ABOUT 900 RPM OR SO. STILL, THERE WAS NO ADVERSE YAW AT ALL. AFTER LNDG, WE TURNED OFF THE RWY AND RAN AFTER LNDG CHKS AND I SAW 395 RPM ON L PROP GAUGE AND LOOKED OUTSIDE TO CONFIRM IT WAS IN FLUX AND IT WAS. DUE TO THE LACK OF CTLABILITY PROBS AND THE CONFLICTING INDICATIONS OF THE GAUGES AND THE BETA AND REVERSE LIGHTS, WE THOUGHT THAT THERE WAS SOME KIND OF INDICATION PROBS AND THEREFORE DID NOT DECLARE AN EMER. THE ENG WAS NOT SHUT DOWN DUE TO THE FACT THAT WITHOUT YAW, THE ENG SEEMED TO BE PRODUCING THRUST AND I DIDN'T WANT TO POSSIBLY AGGRAVATE THE CURRENT PROB BY CHANGING THE CONFIGN OF THE L ENG. THINKING BACK, I SUPPOSE WE COULD HAVE DECLARED AN EMER BUT IN OUR HASTE TO EVALUATE THE SIT AND ENTER DOWNWIND FOR LNDG AND CHKLISTS AND ADVISING FLT ATTENDANTS AND THE LACK OF ANY INDICATION AS FAR AS THE CTL OF THE ACFT, WE DECIDED NO NEED FOR THE DECLARATION.

Data retrieved from NASA's ASRS site as of July 2007 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.