CL65 CAPT COMMENTS ON THE INADEQUACY OF A PROPOSED FAA AIRWORTHINESS DIRECTIVE ON HIS ACFT.

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PREVIOUS ASRS RPT FILED ON CL65 FLAP FAILURE WITHOUT CONFIGN WARNING ON TKOF. ASRS ACTION APPARENTLY SPURRED PROPOSED AIRWORTHINESS DIRECTIVE BY ACR AND FAA. PROPOSED AIRWORTHINESS DIRECTIVE CALLS FOR A VISUAL INSPECTION OF FLAP POS PRIOR TO EVERY TKOF. CAUSE OF FLAP FAILURE RPTED TO BE FLAP ACTUATOR WITH A POOR HISTORY OF RELIABILITY. FURTHER ASRS ACTION IS WARRANTED BECAUSE: 1) EMPHASIS HAS BEEN PLACED ON FAILURE OF FLAP ACTUATOR; NOT FAILURE OF CONFIGN WARNING AND FLAP INDICATION SYS. 2) FLAP SYS HAS BEEN SHOWN TO BE VULNERABLE TO LATENT SINGLE POINT FAILURE IN BOTH CONFIGN WARNING SYS AND FLAP INDICATION SYS. 3) EXTERNAL VISUAL INSPECTION NOT PRACTICAL IN REAL WORLD CONDITIONS; ESPECIALLY WINTER OPS WITH DEICING; AND FLT TRAINING. AT THIS TIME THE COMPANY IS OBJECTING TO THE CONDITIONS OF PROPOSED VISUAL INSPECTION; AND NO TIME LINE FOR CORRECTION OF ACTUATOR PROB. I AM CONCERNED THAT LITTLE OR NO ATTN IS BEING GIVEN TO THE DESIGN OF THE FLAP INDICATION SYS AND CONFIGN WARNING SYS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THIS RPT WAS NOT GENERATED BY A FURTHER INCIDENT. THE RPTR THINKS THE PROPOSED FAA AIRWORTHINESS DIRECTIVE NOTE DOES NOT ADEQUATELY ADDRESS THE PROB IN 2 AREAS: 1) THE FLAP POS IS ON THE TKOF WARNING SYS. WHEN ALL TKOF WARNING ITEMS HAVE BEEN SATISFIED; A 'TO CONFIGN OK' GREEN MESSAGE IS DISPLAYED ON THE EICAS SCREEN. IF ANY ITEM IS NOT SATISFIED; AN AURAL WARNING AND A VOICE MESSAGE IS GIVEN TO THE CREW WHEN THE THROTTLES ARE ADVANCED. THE PROB WITH THE CURRENT SYS IS THAT THE FLAP POS SENSING DOES NOT COME FROM THE ACTUAL FLAP POS; BUT INDIRECTLY FROM THE FLAP ELECTRICAL MOTOR. THE SENSING SYS CAN SENSE CORRECT POS; YET THE FLAPS BE INCORRECTLY SET. THE VISUAL INSPECTION WHICH IS SUPPOSED TO OVERCOME THIS PROB IS IMPRACTICAL. IT REQUIRES AN EXTERNAL VISUAL INSPECTION BY A CREW MEMBER; AFTER THE FLAPS HAVE BEEN POSITIONED FOR TKOF. POSITIONING THE FLAPS AT THE GATE OR HAVING A CREW MEMBER EXIT THE ACFT AFTER TAXI HAS BEGUN IS IMPRACTICAL AND UNSAFE. WHAT IS NEEDED IS A MEANS TO MEASURE THE ACTUAL FLAP POS. 2) THE FLAPS ARE DRIVEN BY AN ELECTRONIC MOTOR WHICH DRIVES 'TELEFLIX CABLES' WHICH THEN DRIVE JACK SCREWS AT THE END OF EACH FLAP. THIS SYS HAS APPARENTLY PROVEN UNRELIABLE AND PRONE TO SINGLE POINT FAILURES. THE RPTR IS CONCERNED FLAP RELIABILITY IS NOT BEING ADEQUATELY ADDRESSED BY THE PROPOSED FAA AIRWORTHINESS DIRECTIVE NOTE.