Narrative:

Received an air ambulance mission to fly from one hospital to another hospital (34 NM sse). WX was VFR at departure/destination hospitals. Radar was checked prior to departure for thunderstorms, none were in the flight path. After departure, flew a heading of 159 degrees and an altitude of 2500 ft MSL. About 10 mins into the flight, a scattered layer at 1600/1700 ft MSL became overcast, so I descended below the overcast and continued the flight. About another 5 mins into the flight, the overcast started forcing us lower to about 350 ft to 400 ft AGL. I initiated a 180 degree turn. At about 90 degrees into the turn, the aircraft encountered IMC conditions. At that point I initiated a climb and reported to approach that I was inadvertent IFR and requested an IFR clearance. Approach issued a clearance and during the VOR approach, VFR conditions were entered and aircraft was returned to destination hospital under VFR. I should have returned to departure hospital prior to entering IMC.

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Original NASA ASRS Text

Title: ROTARY FLT RETURNS TO DEP HOSPITAL AFTER EXPERIENCING IMC IN VFR FLT ON THE WAY TO DEST HOSPITAL.

Narrative: RECEIVED AN AIR AMBULANCE MISSION TO FLY FROM ONE HOSPITAL TO ANOTHER HOSPITAL (34 NM SSE). WX WAS VFR AT DEP/DEST HOSPITALS. RADAR WAS CHKED PRIOR TO DEP FOR TSTMS, NONE WERE IN THE FLT PATH. AFTER DEP, FLEW A HEADING OF 159 DEGS AND AN ALT OF 2500 FT MSL. ABOUT 10 MINS INTO THE FLT, A SCATTERED LAYER AT 1600/1700 FT MSL BECAME OVCST, SO I DSNDED BELOW THE OVCST AND CONTINUED THE FLT. ABOUT ANOTHER 5 MINS INTO THE FLT, THE OVCST STARTED FORCING US LOWER TO ABOUT 350 FT TO 400 FT AGL. I INITIATED A 180 DEG TURN. AT ABOUT 90 DEGS INTO THE TURN, THE ACFT ENCOUNTERED IMC CONDITIONS. AT THAT POINT I INITIATED A CLB AND RPTED TO APCH THAT I WAS INADVERTENT IFR AND REQUESTED AN IFR CLRNC. APCH ISSUED A CLRNC AND DURING THE VOR APCH, VFR CONDITIONS WERE ENTERED AND ACFT WAS RETURNED TO DEST HOSPITAL UNDER VFR. I SHOULD HAVE RETURNED TO DEP HOSPITAL PRIOR TO ENTERING IMC.

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