Falcon 2000
Maintenance Airframe; Maintenance Powerplant
Maintenance Technician 26
Communication Breakdown; Distraction; Situational Awareness
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Human Factors; Incorrect / Not Installed / Unavailable Part; Procedure
May 2014. Dassault Falcon 2000. Airport: ZZZ at a Fixed Base Operator's (FBO) hangar. I was working with Mechanic Y. During troubleshooting of the Fuel Distribution System; the Left Hand (L/H) and Right Hand (R/H) Fuel Crossfeed Valve Actuators were removed to inspect valve mechanism for freedom of movement and on the R/H side for proper Part Number (P/N) installed. During these checks it was discovered that the RH valve was clocked 180 degrees out of position. Both valves were then reinstalled; safetied and operational checks completed; all checks were good (for both valves). It was noted [at that time] that the RH valve was recently changed [by a Vendor] and Quality Assurance Representative (Rep) X was notified. An investigation ensued involving the Vendor who last replaced the R/H valve actuator; two days prior; (Dassault ZZZ). I was then contacted several times [during] the following two days by our Quality Assurance group for a detailed explanation as to how the valve could be assembled 180-degrees out of position. Several days later I was called and conferenced in with our Quality Assurance Rep X; Dassault Falconjet Representative and two Federal Agency Representatives to explain in detail what we observed/noted prior to removal of the crossfeed valve actuators. Followed by what we saw with the actuators off [removed] and then with the actuators reinstalled. It was discovered in that discussion that the L/H Crossfeed Valve Actuator was removed and reinstalled without documentation. The following day I was notified by Quality Assurance Rep X that we had performed undocumented maintenance and that I should file a report. This event will be a constant reminder to be diligent about documenting items/systems that get disturbed during other maintenance for any reason.
Reporter stated the Falcon 2000 came to their Station with logbook write-ups about difficulties with the Fuel Distribution System feeding into one tank. The right hand crossfeed valve motor actuator was previously replaced by a Contract Maintenance Vendor at a different Repair Station two days prior for similar fuel problems. After performing multiple troubleshooting checks of the system without finding any specific cause for the unwanted transfer of fuel; their Technical Representative suggested separating the crossfeed valve motor actuator from the actual valve body and verifying the actual valve operated freely; and than checking to see if the Index Marks on the motor actuator shaft lined up with the slot (receiver) on the valve body. That's when he noticed the flat; blade like end of the crossfeed valve's motor actuator shaft had been incorrectly rotated 180-degrees out of position from the index marks; causing the crossfeed valve to be 'Open' when the crossfeed valve switch in the cockpit was in the 'Off' position. Reporter stated the Fuel Crossfeed Valve and Motor Actuator Assembly are generally installed as a unit with a locking clamp and a locator screw to prevent incorrect installation of the assembly. That's why initially no one thought the valve/actuator was the problem. Removal and Replacement (R/R) of only the motor actuator for the Crossfeed Valve is also an acceptable procedure. The issue about his failing to document removal of the Left Crossfeed Valve Assembly only became an issue 'after' he explained that his removal of both crossfeed valves was to see if anything was different between the two valves. No further problems have been noted with the Fuel Crossfeed System since.
An Aircraft Maintenance Technician (AMT) describes how their troubleshooting efforts identified the cause of a Fuel Distribution System problem on a Dassault Falcon 2000 aircraft. A previous motor actuator replacement installation at the Right Crossfeed Valve Assembly by a Contract Maintenance Vendor was found to be 180-degrees out of position.