CRJ200 CREW RECEIVES EICAS L ENG OIL PRESS AT FL360 AND DESCENDS TO FL200 AFTER DECLARING AN EMERGENCY. ENG DOES NOT MEET CRITERIA FOR SHUT DOWN UNTIL 40 MINUTES LATER. SINGLE ENG LANDING AT DESTINATION FOLLOWS.

Narrative

ON MAR/MON/07 WHILE OPERATING AS THE PF; WE WERE FACED WITH AN EMER. WHILE CRUISING AT FL360 WE RECEIVED A 'L ENG OIL PRESSURE' MESSAGE FROM THE EICAS SYS. I STATED TO THE CAPT THAT I HAD THE CTLS AND THE RADIOS AND ASKED HIM TO REFER TO THE QRH FOR THE L ENG OIL PRESSURE MESSAGE. I CONTACTED CTR AND DECLARED AN EMER; REQUESTING A LOWER ALT DUE TO A POSSIBLE ENG PROB. WE DSNDED TO FL200 WHERE WE WERE ABLE TO MAINTAIN ALT WITH THE L THRUST LEVEL AT IDLE (AS PER THE QRH) AND THE R THRUST LEVER SET AT THE MAX CONTINUOUS CRUISE SETTING. THE QRH EMER PROC WAS FOLLOWED AND COMPLETED. AT THIS TIME THE PARAMETERS REQUIRING AN ENG SHUTDOWN WERE NOT MET. THESE PARAMETERS ARE: ENG OIL PRESSURE BELOW 25 PSI OR THE OIL TEMP INDICATING HIGH OR LOW ABNORMALLY. WHILE MONITORING THE ENG PERFORMANCE; AS INSTRUCTED BY THE QRH; MAINT WAS CONSULTED AND INFORMED OF THE ENG INDICATIONS. ALL OTHER ENG INDICATIONS WERE NORMAL EXCEPT THE OIL PRESSURE. THE OIL PRESSURE FLUCTUATED BTWN 29 PSI AND 50 PSI WITH A FEW DROPS IN PRESSURE TO 25 PSI; IMMEDIATELY RETURNING TO THE 29-50 PSI RANGE. APPROX 40 MINS PASSED WHILE MONITORING THE ENG PERFORMANCE. DURING THIS 40 MINS; DISPATCH; MAINT; AS WELL AS CHIEF PLT WERE CONSULTED. ALL PARTIES AGREED THAT THE BEST COURSE OF ACTION WOULD BE TO LEAVE THE L ENG RUNNING IF POSSIBLE. THE CHIEF PLT RECOMMENDED A NORMAL 2 ENG APCH AND LNDG IN ZZZ. THE CAPT AND I DISCUSSED OUR CONCERNS WITH A NORMAL LNDG WITH FLAPS AT 45 DEGS DUE TO THE POSSIBILITY OF AN ENG FAILURE AND A POSSIBLE GAR WITH A SINGLE OPERATING ENG. WE AGREED THAT A FLAPS 20 DEG SINGLE ENG PROC CONFIGN WOULD BE THE SAFEST COURSE OF ACTION. WE AGAIN CONFERRED WITH THE CHIEF PLT; MAINT; AND DISPATCH CONCERNING THE MATTER. ALL PARTIES AGAIN AGREED THAT A FLAPS 20 DEG CONFIGN WOULD BE THE SAFEST COURSE OF ACTION. THE L ENG WOULD BE KEPT AT IDLE AND CONSIDERED INOP. IMMEDIATELY FOLLOWING THE DISCUSSION; ON A DSCNT TO 8000 FT IN ZZZ AIRSPACE; THE L ENG OIL PRESSURE MESSAGE FROM THE EICAS WAS ANNUNCIATED AGAIN. THE OIL PRESSURE HAD DROPPED TO THE 22-24 PSI RANGE; REQUIRING THE CAPT TO AGAIN REFER TO THE QRH. UNDER THE CONDITIONS AT THAT TIME THE PARAMETERS WERE MET FOR AN INFLT ENG SHUTDOWN AND SUBSEQUENT SINGLE ENG APCH AND LNDG IN ZZZ. UPON COMPLETION OF THE QRH PROC; ALL REQUIRED CHKLISTS WERE COMPLETED AND WE RECEIVED VECTORS FROM ZZZ APCH FOR A VISUAL APCH TO RWY 18L. THE SINGLE ENG APCH AND LNDG PROCS WERE FOLLOWED TO AN UNEVENTFUL LNDG. NO FURTHER EMER OR ABNORMAL PROCS WERE REQUIRED. ALL REQUIRED CHKLISTS WERE COMPLETED AND THE FLT SEGMENT ENDED AFTER TAXIING TO REMOTE PARKING.