Flight crew of mdt had erratic torque readings after takeoff. Returned, landed.

Attributes
ACN	126085
Time
Date	198910
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : fxm airport : fsm
State Reference	AR
Altitude	msl bound lower : 700 msl bound upper : 800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : fsm
Operator	common carrier : air carrier
Make Model Name	Medium Transport, High Wing, 2 Turboprop Eng
Flight Phase	climbout : takeoff climbout : initial landing other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 250 flight time total : 2000
ASRS Report	126085
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa
Resolutory Action	flight crew : declared emergency flight crew : overcame equipment problem
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

After takeoff (approximately 400' AGL), left torque gauge began giving very erratic readings. Flight crew attempted to assess problem and decided an engine shutdown and return for landing was in best interest of safety of flight. Notified fsm tower of our intentions (we did declare an emergency). They had equipment standing by for us. After caging left engine, we called for and completed all normal/abnormal/emergency checklists as appropriate. We entered a left downwind and executed smooth landing. Maintenance check showed a faulty np sensor was giving us erroneous torque readings. Maximum torque is 108%. We made a reduced power takeoff (94%). Gauge was fluctuating between 40-120%.

Original NASA ASRS Text

Title: FLT CREW OF MDT HAD ERRATIC TORQUE READINGS AFTER TKOF. RETURNED, LANDED.

Narrative: AFTER TKOF (APPROX 400' AGL), LEFT TORQUE GAUGE BEGAN GIVING VERY ERRATIC READINGS. FLT CREW ATTEMPTED TO ASSESS PROB AND DECIDED AN ENG SHUTDOWN AND RETURN FOR LNDG WAS IN BEST INTEREST OF SAFETY OF FLT. NOTIFIED FSM TWR OF OUR INTENTIONS (WE DID DECLARE AN EMER). THEY HAD EQUIP STANDING BY FOR US. AFTER CAGING LEFT ENG, WE CALLED FOR AND COMPLETED ALL NORMAL/ABNORMAL/EMER CHKLISTS AS APPROPRIATE. WE ENTERED A LEFT DOWNWIND AND EXECUTED SMOOTH LNDG. MAINT CHK SHOWED A FAULTY NP SENSOR WAS GIVING US ERRONEOUS TORQUE READINGS. MAX TORQUE IS 108%. WE MADE A REDUCED PWR TKOF (94%). GAUGE WAS FLUCTUATING BTWN 40-120%.

Data retrieved from NASA's ASRS site as of August 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.