Narrative:

While climbing through 12000 ft on climb; we experienced a loud bang accompanied by the airplane shaking. Almost immediately; the left engine oil pressure went to 0 psi. I called for the severe engine damage in-flight checklist and declared an emergency with ATC. We were cleared to ZZZ. After completing all checklists we informed the flight attendant and passenger of the situation. We also contacted dispatch and maintenance control about an overweight landing. They told us it would be ok as long as we were under 250 FPM on touchdown. When we landed; it was at 100 FPM. After deplaning the passenger; we inspected the aircraft. It was then that we discovered that the top half of the core cowl was gone. Callback conversation with reporter revealed the following information: the reporter stated after the first loud bang the oil pressure instantaneously went to zero followed by the oil quantity indication. The engine was shut down per the checklist. On the ground it was discovered the top half of the core cowl was missing; and oil lines were severed. No details on how the core cowling came loose. Callback conversation with reporter acn 665653 revealed the following information: the reporter stated that after the bang was heard; the left engine oil pressure dropped to zero followed by the oil quantity indicator. The engine shutdown checklist was accomplished and the engine shut down. Ground inspection of the engine revealed the entire upper half of the core cowling was missing and the engine oil supply tank was gone. No information on cause of core cowling departing aircraft.

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Original NASA ASRS Text

Title: A CRJ200 CLBING THROUGH 12000 FT DECLARED AN EMER AND DIVERTED DUE TO LOSS OF L ENG OIL PRESSURE AND QUANTITY. ENG SHUTDOWN. ON GND FOUND TOP HALF OF CORE COWL MISSING. OIL LINES SEVERED AND OIL TANK MISSING.

Narrative: WHILE CLBING THROUGH 12000 FT ON CLB; WE EXPERIENCED A LOUD BANG ACCOMPANIED BY THE AIRPLANE SHAKING. ALMOST IMMEDIATELY; THE L ENG OIL PRESSURE WENT TO 0 PSI. I CALLED FOR THE SEVERE ENG DAMAGE INFLT CHKLIST AND DECLARED AN EMER WITH ATC. WE WERE CLRED TO ZZZ. AFTER COMPLETING ALL CHKLISTS WE INFORMED THE FLT ATTENDANT AND PAX OF THE SIT. WE ALSO CONTACTED DISPATCH AND MAINT CTL ABOUT AN OVERWT LNDG. THEY TOLD US IT WOULD BE OK AS LONG AS WE WERE UNDER 250 FPM ON TOUCHDOWN. WHEN WE LANDED; IT WAS AT 100 FPM. AFTER DEPLANING THE PAX; WE INSPECTED THE ACFT. IT WAS THEN THAT WE DISCOVERED THAT THE TOP HALF OF THE CORE COWL WAS GONE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED AFTER THE FIRST LOUD BANG THE OIL PRESSURE INSTANTANEOUSLY WENT TO ZERO FOLLOWED BY THE OIL QUANTITY INDICATION. THE ENG WAS SHUT DOWN PER THE CHKLIST. ON THE GND IT WAS DISCOVERED THE TOP HALF OF THE CORE COWL WAS MISSING; AND OIL LINES WERE SEVERED. NO DETAILS ON HOW THE CORE COWLING CAME LOOSE. CALLBACK CONVERSATION WITH RPTR ACN 665653 REVEALED THE FOLLOWING INFO: THE RPTR STATED THAT AFTER THE BANG WAS HEARD; THE L ENG OIL PRESSURE DROPPED TO ZERO FOLLOWED BY THE OIL QUANTITY INDICATOR. THE ENG SHUTDOWN CHKLIST WAS ACCOMPLISHED AND THE ENG SHUT DOWN. GND INSPECTION OF THE ENG REVEALED THE ENTIRE UPPER HALF OF THE CORE COWLING WAS MISSING AND THE ENG OIL SUPPLY TANK WAS GONE. NO INFO ON CAUSE OF CORE COWLING DEPARTING ACFT.

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.