Date: 201404
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: Jet/Long Ranger/206
Operator: Air Taxi
Operating under: Part 135
Mission: Ambulance
Flight phase: Parked
Aircraft component: Main Rotor Hub
Reporter organization: Air Taxi
Reporter function: Technician
Reporter qualification: Maintenance Powerplant; Maintenance Airframe
Human factors: Communication Breakdown
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Aircraft In Service At Gate
Result: General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Aircraft; Human Factors
Primary problem: Human Factors

Narrative: Bell 407 helicopter recently added to fleet. Bolts for Rotor Head Pitch Horn and Buffer pad to Rotor Blade attachment safety wired backwards. Aircraft had just arrived at the Base. While doing a Daily [Check] the pilot found the safety wire pulling in the wrong direction. Aircraft was taken of service and bolts were Torque Checked and re-safety wired in the correct direction. [Recommend] when inspecting items; don't just look at the safety wire and assume it is in the correct direction. [Also]; don't assume that factory safety wire is correct [either]. Flight delay.

Callback: Reporter stated the interior of the Bell-407 helicopter was recently upgraded to a medical evac operation. One of their pilot's; who had previously flown the same -407 on several trips totaling about thirty hours; had some extra time prior to another flight and while checking the Main Rotor Head noticed a section of safety wire that appeared to have been installed backwards. When he (reporter) was asked to check the issue out; he realized there were actually eight safety wire sections involving 16-bolts that were safetied backwards. The bolts secured the Grip Assembly [Blade Mounting Fork] to the Rotor Head Pitch Horn; two upper bolts and two lower bolts; four per blade section.Reporter stated he feels that particular incident was a real Human Factors issue that involved 'Assumptions' by several parties. The type of safety wiring involved was 'Swadge-locked' cables; that are 'swedged' (crimped) at the ends of the safety wire with a 'Cap'; instead of the traditional twisted pigtail end. Not uncommon for technicians to assume that type of safety wiring (swaged-lock) had come from the Manufacturer and must be routed correctly. But that same method of safety wiring can; and has been; used by other technicians who can easily purchase the necessary tools. Also; the Main Rotor Head could have been previously replaced; adding to the question of how the backwards safety wiring could have occurred and not have been caught during inspections. The torque seals [mucky-pucks] were still in place; indicating the bolts had not backed-off. He has ten years experience as an Aircraft Maintenance Technician (AMT).



Synopsis: An Aircraft Maintenance Technician (AMT) reports that eight sections of safety wire involving 16 bolts that secure the Rotor Head Pitch Horn and buffer pad to the Rotor Blade attachments; were found safety wired backwards. Pilot for the Bell-407 helicopter had initially noticed that one safety wire section appeared to be incorrect.