NEW ENGLAND LIFE FLIGHT INC

ENTIRE CREW NOTICED FUEL SMELL IN CABIN AND COCKPIT DURING TAKEOFF CLIMB PASSING THROUGH 500' AGL FROM PLYMOUTH AIRPORT -- COULD NOT DUPLICATE.

TAIL GEARBOX CHIP LIGHT ILLUMINATED ON GROUND DURING TRAINING.

DURING AIRCRAFT 800 HOUR/ 36 MONTH INSPECTION A CRACK WAS DISCOVERED ON THE MAIN TRANSMISSION DECK AT APPROXIMATELY AIRFRAME STATION 4000, AT FORWARD RIGHT MAIN TRANSMISSION TORQUE STRUT MOUNT. UPON FURTHER INSPECTION INTO THE CRACK IT WAS DISCOVERED THAT ON THE UNDERSIDE THE DECK DOUBLER (RIB) WAS ALSO CRACKED AT SAME LOCATION.

OIL PRESURE LOW R EICAS MESSAGE ON DEPARTURE FROM NEW YORK STEWART INTERNATIONAL AIRPORT (KSWF). FLIGHT DIVERTED BACK TO KSWF FOR A PRECAUTIONARY LANDING. RETURN FLIGHT, LANDING AND TAXI WERE UNEVENTFUL.

WHILE AT 2000' MSL ENROUTE AT 2200EDT BETWEEN KPYM (BASE OF OPERATIONS) AND FALMOUTH HOSPITAL, MASSACHUSETTS WITH A NURSE AND PARAMEDIC ONBOARD, TO PICKUP A PATIENT AT FALMOUTH HOSPITAL, DETECTED A FUEL FUME ODOR FROM AIRCRAFT ENVIRONMENTAL CONTROL SYSTEM (ECS) VENTILATION. SECURED ECS VENTILATION SYSTEM AND THEN BRIEFLY CRACKED OPENED SLIDING WINDOWS ON COCKPIT DOORS AND CABIN DOORS TO QUICKLY AND THOROUGHLY ELIMINATE SMELL. ABORTED THE MEDICAL TRANSPORT MISSION, DETERMINED SAFE LANDING CRITERIA, AND COMPLETED AN UNEVENTFUL SHORT FLIGHT BACK TO KPYM (BASE OF OPERATIONS).

DURING STRAIGHT AND LEVEL FLIGHT BACK TO THE AIRPORT, THE HVAC SYSTEM STOPPED FUNCTIONING. ATTEMPTED TO CYCLE POWER ON THE CONTROL UNIT, WHICH DID NOT RESTORE FUNCTION. ABOUT A MINUTE LATER, A CREWMEMBER IN THE REAR CABIN REPORTED A BURNING SMELL. CHECKED THE CIRCUIT BREAKER PANEL, AND FOUND A POPPED BREAKER. AT THIS POINT, TURNING FINAL TO THE AIRPORT. WHILST ON FINAL, THE BURNING SMELL PENETRATED THE COCKPIT. NO SMOKE WAS OBSERVED. A NORMAL LANDING WAS MADE, FOLLOWED BY A NORMAL SHUT DOWN. AIRCRAFT INSPECTED, COULD NOT DUPLICATE THE ISSUE.