Date: 201208
Local time of day: 0601-1200
Location: 50MO.Airport, MO
Aircraft: Jet/Long Ranger/206
Operator: Air Carrier
Mission: Ambulance
Flight phase: Parked
Aircraft component: Oxygen System/General
Reporter organization: Air Carrier
Reporter function: Technician
Reporter qualification: Maintenance Powerplant; Maintenance Airframe
Human factors: Communication Breakdown; Troubleshooting
Second reporter function: Lead Technician
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Maintenance
When detected: Pre-flight
Result: General Maintenance Action
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: The aircraft was released for service. The Mechanic had found the collective bolt did not have a nut on the bolt. It had been looked at several times [and] was missed by several people. The next thing was the chin bubble had exited the aircraft. When looked at; there was no sealant holding the seal in. The instructions ask to do this. The oxygen system line was installed on the wrong valve. The lines were not tagged. If the lines were tagged this would not have happened.


Second narrative: The aircraft came into the shop for a complete rollover inspection into the FAA Approved Aircraft Inspection Program (AAIP) Chapter 5A and a main rotor mast change for mast inspection. There were four technicians involved working staggered 12 hour shifts. I believe the aircraft was in the Shop for four days getting this work completed and waiting for the weather to clear for return to service at the base. During the night shift; the mast had been removed for Tear-Down Inspection and a serviceable replacement was to be installed. Most of the inspections had been completed. When I came on duty to relieve the first night Technician; the mast was ready to install. There was a two hour overlap before the next day Technician came on duty to relieve the other night Mechanic and I continued to work on getting the inspections completed as the remaining night Technician completed the installation of the serviceable mast. I did not inspect his installation as I generally try to do as a safety measure. The oncoming day Technician also did not inspect the installation. Later that day I was inspecting the Top Deck for FOD when I discovered a nut and washer laying up under a hose on the deck. I began looking at everything to try to determine where they might have been missed and could not see anything missing. I showed them to the other Technician and he looked around the deck area and couldn't see anything missing either. I then took the nut and washer and laid them on the workbench next to the aircraft on a white rag until we could see where they came from. The night shift came on again and I forgot to tell them about the hardware I had discovered. The maintenance on that aircraft was completed and another aircraft came in for engine work in that same day. I didn't know what happened to the hardware. The base pilot came in to pick up the aircraft and as he was preparing for the Operational Check Flight I briefed him on the maintenance that had been performed. I did not remain with him during the preflight. I left the shop for a trip to a base. The operations check flight and return to service were conducted in my absence. After the aircraft had returned to base; the base Mechanic was cleaning up some residual oil on the deck when he discovered the hardware missing from the lower Collective lever bolt on the swashplate. At least 3 people were working and looking in that specific area and did not see the hardware missing either during maintenance; or preflight. In all of my years of maintenance I have never seen such an extensive chain of events leading to such a 'near miss.' I have no idea how to definitively prevent this from happening again. The work shifts and location have recently been changed and the technicians have not worked together as a team before. The technicians attempting to adapt to the new conditions and venue may have played a part. There was no implied pressure whatsoever from Management concerning a time frame for this project and integrity of the aircraft is always our primary focus.


Synopsis: Several maintenance discrepancies including an unsecured bolt on the top deck of a Bell 206 were missed during a final inspection. A Mechanic noticed the unsecured bolt after a check flight.