A FOKKER 100 ON TAXI OUT FOR TKOF RETURNED TO THE GATE DUE TO BINDING AILERONS CAUSED BY AN UNCLAMPED HYD LINE IN THE MAIN GEAR WELL HYD TUNNEL.

Narrative

MYSELF AND ANOTHER TECHNICIAN HAD BEEN SENT ON A ROAD TRIP TO ZZZ FROM ABC TO REPAIR A HYD LEAK ON AN F100. WE HAD DISCOVERED A SMALL PIN-HOLE LEAK IN A LINE IN THE MAIN GEAR WHEEL WELL KEEL BEAM AREA. ACCESS TO THE LINE IS DIFFICULT AT BEST. WE DISCONNECTED THE LINE AND INSTALLED A FLEX-LINE LEAVING THE OLD HARD LINE IN PLACE; TO AID THE PERSON WHO REPLACES THE TEMPORARY FLEX LINE WITH THE HARD LINES ROUTING. THIS IS COMMON PRACTICE. WE TOOK CARE IN ROUTING AND SECURING THE FLEX LINE WELL CLR OF ANY MOVING COMPONENTS. ON TAXI OUT; THE FLC NOTICED A BINDING IN THE AILERONS AND RETURNED TO THE GATE. WE FOUND THAT THE HARD LINE THAT WAS LEFT IN PLACE WITH ITS 'B' NUT WAS NOW INTERFERING WITH THE AILERON BELLCRANK ASSEMBLY. WHAT HAD KEPT THE LINE CLR OF THE BELLCRANK WAS THAT IT WAS CONNECTED TO A FITTING. NO CLAMPS OR GUARDS ARE CURRENTLY PROVIDED IN THIS AREA; AND THERE ARE MORE LINES THAT ARE RUN VERY CLOSE TO THE BELLCRANK WITH VERY LITTLE CLRNC. MY CONCERN IS IF A LINE BREAKS OR COMES LOOSE IT COULD JAM THE AILERON CTLS. THIS COULD BE PREVENTED BY CLAMPING THE LINES IN PLACE ON THE VERT RUN. IN THE PAST; I HAVE ALWAYS FOUND THAT ANY HYD LINE RUNNING IN A CRITICAL AREA IS ADEQUATELY CLAMPED TO ENSURE CLRNC WHETHER IT IS CONNECTED OR NOT. ACCESSIBILITY WAS ALSO A FACTOR. IT WAS DIFFICULT TO REACH; LET ALONE SEE. IF YOU CAN PICTURE WORKING THROUGH A SQUARE HOLE TO ACCESS THE FAR END OF A RECTANGULAR BOX. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE INTERFERENCE TO THE AILERON CABLE QUADRANT WAS CAUSED BY THE DISCONNECTED LEAKING SOLID HYD LINE. THE RPTR SAID NONE OF THE SOLID LINES IN THE KEEL BEAM HYD TUNNEL WERE CLAMPED. THE RPTR SAID THE HYD TUNNEL MEASURES APPROX 30 INCHES LONG BY 14 INCHES HIGH WITH A SMALL ACCESS HOLE IN THE AFT L SIDE. THE RPTR STATED THE LINES WERE NOT CLAMPED DUE TO THE VERY LIMITED SPACE TO GAIN ACCESS TO THE LINES FOR CLAMPING. THE RPTR SAID ANY SOLID HYD LINE LOOSE OR BREAKING IN THIS AREA COULD BE A CRITICAL SIT FOR THE AILERON CTL SYS.