Narrative:

Aircraft had received a za inspection in sep/xa/99. On or about mar/tue/00, aircraft was on final approach to ZZZ, united states, when crew experienced loss of aileron control. An uneventful landing was made using asymmetric thrust and rudder. Maintenance personnel investigated and upon removal of r-hand aileron servo inspection panel, a bolt, P/north f50b111025008, fell out. Due to markings observed, it is surmised that this bolt had been lodged between the inspection panel and the secondary artificial feed unit (afu) arm of the aileron servo. With the inspection plate off, the aileron control reacted properly. Maintenance personnel from FBO aviation then inspected all primary flight control system. No other defects were found. It is believed that the condition leading to this incident occurred during the za inspection. During that inspection these bolts are removed to lubricate the aileron servo. It is thought that the bolt in question was removed and left in the wing while the servo was being lubricated. When the servo was reinstalled, this bolt had somehow been bumped or moved and could not be found. The technician believing the bolt to be somewhere other than in the wing, searched the floor and adjacent toolbox but could not find it. A replacement bolt was purchased, the servo installed, inspected and the panel reinstalled. Finally, about 7 months after this inspection, it appears this bolt was jostled into a position which caused loss of aileron control. On mar/tue/00, he stated that he remembered laying both bolts on the floor just before reinstalling the servo. He believes he accidentally kicked the bolt in question and that is how he lost it. This is difficult to comprehend since the bolt was found in the wing, 3 ft off the ground. It is much more probable that he left the bolt in the wing and forgot about it. Callback conversation with reporter revealed the following information: the reporter stated the foreman was advised of the missing bolt but did not pass this discrepancy along to quality control supervisor. The reporter said another bolt was purchased and installed and the aileron system tested ok. The reporter stated about 2 months ago the airplane experienced an aileron stiffness report and was checked by the owner's local technicians who could not duplicate the report. The reporter said the airplane operated for 7 months until the bolt jammed between the aileron actuator inspection plate and the aileron actuator assembly. The reporter said the FAA investigated this incident and required a plan to prevent this type of event. The reporter stated the company has put in place a procedure that requires the quality control supervisor when advised of missing fittings, components, and fasteners to initiate an intensified inspection and find the missing item.

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Original NASA ASRS Text

Title: A FALCON 900 ON FINAL APCH CREW EXPERIENCED LOSS OF AILERON CTL CAUSED BY A LOOSE BOLT LODGED BTWN THE AILERON SERVO INSPECTION PANEL AND THE AILERON ACTUATOR.

Narrative: ACFT HAD RECEIVED A ZA INSPECTION IN SEP/XA/99. ON OR ABOUT MAR/TUE/00, ACFT WAS ON FINAL APCH TO ZZZ, UNITED STATES, WHEN CREW EXPERIENCED LOSS OF AILERON CTL. AN UNEVENTFUL LNDG WAS MADE USING ASYMMETRIC THRUST AND RUDDER. MAINT PERSONNEL INVESTIGATED AND UPON REMOVAL OF R-HAND AILERON SERVO INSPECTION PANEL, A BOLT, P/N F50B111025008, FELL OUT. DUE TO MARKINGS OBSERVED, IT IS SURMISED THAT THIS BOLT HAD BEEN LODGED BTWN THE INSPECTION PANEL AND THE SECONDARY ARTIFICIAL FEED UNIT (AFU) ARM OF THE AILERON SERVO. WITH THE INSPECTION PLATE OFF, THE AILERON CTL REACTED PROPERLY. MAINT PERSONNEL FROM FBO AVIATION THEN INSPECTED ALL PRIMARY FLT CTL SYS. NO OTHER DEFECTS WERE FOUND. IT IS BELIEVED THAT THE CONDITION LEADING TO THIS INCIDENT OCCURRED DURING THE ZA INSPECTION. DURING THAT INSPECTION THESE BOLTS ARE REMOVED TO LUBRICATE THE AILERON SERVO. IT IS THOUGHT THAT THE BOLT IN QUESTION WAS REMOVED AND LEFT IN THE WING WHILE THE SERVO WAS BEING LUBRICATED. WHEN THE SERVO WAS REINSTALLED, THIS BOLT HAD SOMEHOW BEEN BUMPED OR MOVED AND COULD NOT BE FOUND. THE TECHNICIAN BELIEVING THE BOLT TO BE SOMEWHERE OTHER THAN IN THE WING, SEARCHED THE FLOOR AND ADJACENT TOOLBOX BUT COULD NOT FIND IT. A REPLACEMENT BOLT WAS PURCHASED, THE SERVO INSTALLED, INSPECTED AND THE PANEL REINSTALLED. FINALLY, ABOUT 7 MONTHS AFTER THIS INSPECTION, IT APPEARS THIS BOLT WAS JOSTLED INTO A POS WHICH CAUSED LOSS OF AILERON CTL. ON MAR/TUE/00, HE STATED THAT HE REMEMBERED LAYING BOTH BOLTS ON THE FLOOR JUST BEFORE REINSTALLING THE SERVO. HE BELIEVES HE ACCIDENTALLY KICKED THE BOLT IN QUESTION AND THAT IS HOW HE LOST IT. THIS IS DIFFICULT TO COMPREHEND SINCE THE BOLT WAS FOUND IN THE WING, 3 FT OFF THE GND. IT IS MUCH MORE PROBABLE THAT HE LEFT THE BOLT IN THE WING AND FORGOT ABOUT IT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE FOREMAN WAS ADVISED OF THE MISSING BOLT BUT DID NOT PASS THIS DISCREPANCY ALONG TO QUALITY CTL SUPVR. THE RPTR SAID ANOTHER BOLT WAS PURCHASED AND INSTALLED AND THE AILERON SYS TESTED OK. THE RPTR STATED ABOUT 2 MONTHS AGO THE AIRPLANE EXPERIENCED AN AILERON STIFFNESS RPT AND WAS CHKED BY THE OWNER'S LCL TECHNICIANS WHO COULD NOT DUPLICATE THE RPT. THE RPTR SAID THE AIRPLANE OPERATED FOR 7 MONTHS UNTIL THE BOLT JAMMED BTWN THE AILERON ACTUATOR INSPECTION PLATE AND THE AILERON ACTUATOR ASSEMBLY. THE RPTR SAID THE FAA INVESTIGATED THIS INCIDENT AND REQUIRED A PLAN TO PREVENT THIS TYPE OF EVENT. THE RPTR STATED THE COMPANY HAS PUT IN PLACE A PROC THAT REQUIRES THE QUALITY CTL SUPVR WHEN ADVISED OF MISSING FITTINGS, COMPONENTS, AND FASTENERS TO INITIATE AN INTENSIFIED INSPECTION AND FIND THE MISSING ITEM.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.