Narrative:

Soon after takeoff; passenger had notified flight attendant about the #2 engine cowling opened. She called up to the cockpit. Captain answered call; and then asked me to look out my window at the #2 engine. Seeing the engine cowling open; advised captain. He called 'his controls' and he became the PF at that point. Still on tower frequency; I advised tower of the situation (did not declare emergency because engine was still operating normal); and advised needed to come back for landing. Tower kept us at 1900 ft MSL. We did not exceed 160 KIAS. Vectored back around in the traffic pattern and landed back on runway 19L. Once on the ground and clear of the runway; called operations to get a gate assignment. Upon return to gate; passenger and bags were deplaned. Captain was on the phone with dispatch; maintenance control; or both. We repositioned airplane to the maintenance hangar (taxiing only on #1 engine). Went back to the gate; picked up another aircraft and carried out the flight on that aircraft. Maintenance didn't properly secure engine cowling after line check.

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Original NASA ASRS Text

Title: SF340 FLT CREW HAS #2 ENGINE COWLING OPEN AFTER DEPARTURE.

Narrative: SOON AFTER TKOF; PAX HAD NOTIFIED FLT ATTENDANT ABOUT THE #2 ENG COWLING OPENED. SHE CALLED UP TO THE COCKPIT. CAPT ANSWERED CALL; AND THEN ASKED ME TO LOOK OUT MY WINDOW AT THE #2 ENG. SEEING THE ENG COWLING OPEN; ADVISED CAPT. HE CALLED 'HIS CTLS' AND HE BECAME THE PF AT THAT POINT. STILL ON TWR FREQ; I ADVISED TWR OF THE SITUATION (DID NOT DECLARE EMER BECAUSE ENG WAS STILL OPERATING NORMAL); AND ADVISED NEEDED TO COME BACK FOR LNDG. TWR KEPT US AT 1900 FT MSL. WE DID NOT EXCEED 160 KIAS. VECTORED BACK AROUND IN THE TFC PATTERN AND LANDED BACK ON RWY 19L. ONCE ON THE GND AND CLR OF THE RWY; CALLED OPS TO GET A GATE ASSIGNMENT. UPON RETURN TO GATE; PAX AND BAGS WERE DEPLANED. CAPT WAS ON THE PHONE WITH DISPATCH; MAINT CTL; OR BOTH. WE REPOSITIONED AIRPLANE TO THE MAINT HANGAR (TAXIING ONLY ON #1 ENG). WENT BACK TO THE GATE; PICKED UP ANOTHER ACFT AND CARRIED OUT THE FLT ON THAT ACFT. MAINT DIDN'T PROPERLY SECURE ENG COWLING AFTER LINE CHK.

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