What was found
DURING CRUISE FLIGHT WHILE AT 28,000 FT BOTH PILOTS NOTICED A STRONG ENVIRONMENTAL ODOR IN THE COCKPIT. THE CREW DONNED OXYGEN MASKS AND REVIEWED THEIR CHECKLIST. WHEN THE LEFT CABIN PRESSURE SOURCE WAS SELECTED THE ODOR HAD IMMEDIATELY DISSIPATED. THE FLT WAS COMPLETED AND THE AIRCRAFT LANDED WITHOUT FURTHER INCIDENT. WHILE PERFORMING A GROUND INSPECTION IT WAS NOTED THAT THE RIGHT ENGINE HAD A FISH ODOR TO IT. MAINTENANCE INSPECTED BOTH ENGINES FOR EVIDENCE OF A BIRD STRIKE. NO EVIDENCE WAS FOUND. THE ENGINES WERE OPERATED WITH THE RIGHT BLEED AIR SOURCE SELECTED AND NO ODOR WAS NOTICED. THE AIRCRAFT WAS RETURNED TO SERVICE.