What was found
AIRCRAFT RETURNED TO PLATFORM AFTER THE LT ENGINE STARTED, THE FLIGHT ATTENDANT CALLING CAME ON CONSTANTLY. THE BREAKER P37 CALL SYS WAS RESEATED BUT THE FAILURE CONTINUED. THE FRONT HANDSET WAS VERIFIED, ALL CORRECT. THE BACK HANDSET WAS VERIFIED, DETECTING ATT, PILOT AND P/A LIGHTS TURNED ON. THE HANDSET WAS REPLACED IAW MM 23-40-00, ALL CORRECT.