AT72 diverts due to partial power loss on left engine.

Attributes
ACN	740107
Time
Date	200705
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzzz.airport
State Reference	FO
Altitude	msl single value : 18000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zzzz.artcc
Operator	common carrier : air carrier
Make Model Name	ATR 72
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
ASRS Report	740107
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa other flight crewb
Resolutory Action	flight crew : declared emergency flight crew : diverted to another airport
Supplementary
Problem Areas	Cabin Crew Human Performance Flight Crew Human Performance Aircraft
Primary Problem	Aircraft

Narrative:

While on flight on aircraft X we had a partial engine power loss of approximately 20% power on engine #1. The flight was level at FL180. En route to ZZZZ2 the flight attendant was advised via the intercom system that we were going to do a precautionary landing in the ZZZZ1 airport to ensure the complete safety of the flight. At the time I advised her to prepare the cabin for landing. I immediately proceeded to advise the passenger that we would have to divert to ZZZZ1 due to a technical problem with the aircraft. About 30 NM east of ZZZZ1 we advised ATC of our intentions and also decided to declare an emergency. While performing the procedures dictated by aom volume 1 and flight manual volume 1; the flight attendant continually tried to communicate with us to advise us of some 'sensations' she had felt during takeoff that same morning (a takeoff that was completely uneventful). Due to the intense workload at the time; the flight attendants were advised that we were unable to attend to her conversation/interruptions due to the high workload at the time. We decided to ignore any other attendant call and made an uneventful landing at ZZZZ1.

Original NASA ASRS Text

Title: AT72 DIVERTS DUE TO PARTIAL POWER LOSS ON LEFT ENGINE.

Narrative: WHILE ON FLT ON ACFT X WE HAD A PARTIAL ENG PWR LOSS OF APPROX 20% PWR ON ENG #1. THE FLT WAS LEVEL AT FL180. ENRTE TO ZZZZ2 THE FLT ATTENDANT WAS ADVISED VIA THE INTERCOM SYS THAT WE WERE GOING TO DO A PRECAUTIONARY LNDG IN THE ZZZZ1 ARPT TO ENSURE THE COMPLETE SAFETY OF THE FLT. AT THE TIME I ADVISED HER TO PREPARE THE CABIN FOR LNDG. I IMMEDIATELY PROCEEDED TO ADVISE THE PAX THAT WE WOULD HAVE TO DIVERT TO ZZZZ1 DUE TO A TECHNICAL PROB WITH THE ACFT. ABOUT 30 NM E OF ZZZZ1 WE ADVISED ATC OF OUR INTENTIONS AND ALSO DECIDED TO DECLARE AN EMER. WHILE PERFORMING THE PROCS DICTATED BY AOM VOLUME 1 AND FLT MANUAL VOLUME 1; THE FLT ATTENDANT CONTINUALLY TRIED TO COMMUNICATE WITH US TO ADVISE US OF SOME 'SENSATIONS' SHE HAD FELT DURING TKOF THAT SAME MORNING (A TKOF THAT WAS COMPLETELY UNEVENTFUL). DUE TO THE INTENSE WORKLOAD AT THE TIME; THE FLT ATTENDANTS WERE ADVISED THAT WE WERE UNABLE TO ATTEND TO HER CONVERSATION/INTERRUPTIONS DUE TO THE HIGH WORKLOAD AT THE TIME. WE DECIDED TO IGNORE ANY OTHER ATTENDANT CALL AND MADE AN UNEVENTFUL LNDG AT ZZZZ1.

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.