Date: 201409
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Light: Night
Aircraft: A321
Operator: Air Carrier
Operating under: Part 121
Flight phase: Parked
Aircraft component: Compressor Stator/Vane
Reporter organization: Air Carrier
Reporter function: Technician
Reporter qualification: Maintenance Powerplant; Maintenance Airframe
Human factors: Communication Breakdown
Second reporter function: Inspector
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural FAR
Detector: Person Maintenance
When detected: Routine Inspection
Result: General Maintenance Action
Contributing factors: Aircraft; Human Factors
Primary problem: Human Factors

Narrative: September 2014 was assigned to an Airbus A321 with Job Card (J/C) XXXX09 for # 1 and # 2 Engine Wash. This task was accomplished I.A.W to the letter of J/C XXXX09 as witnessed by inspection department. This aircraft flew for 31-days with no issues to VSV/Bleed problems. Suspect undocumented maintenance was performed between September and October 2014. As stated; with nut missing; this condition would be impossible in this timetable not to have a failure. Event took place at ZZZ Hangar north side. Found during an A-Check. Suspect undocumented maintenance performed at multiple maintenance station visits between September and October 2014. Reference Logbook for Non-routine Line log 'remove and replaced actuator rod end bolt and nut Aircraft Maintenance Manual (AMM) 75-32-41-400. No other defects noted; signed by Inspection. [Recommend that] all maintenance require proper documentation.


Second narrative: During an A-Check Right-hand (R/H) engine inspection; it was discovered that the bolt that connects the VSV actuator to the Stator vane bellcrank was partially backed out and missing the nut. Verbal notification [given] by Inspection Supervisor. Suspect undocumented maintenance between the dates of September 2014 thru October 2014. [Maintenance] Removed and Replaced (R/R) Right engine VSV actuator rod end bolt; washer and nut per AMM 75-32-41-400. No other defects found. Inspected by a different Inspector. Technicians being made aware of impact of undocumented maintenance.

Second callback: Reporter stated he was the Inspector who observed and signed-off the visual inspection for the installation of the bolt and nut assembly that connects the VSV Actuator Fork End to the Stator Vane Bellcrank input rod (lever). They are required to install a new bolt; washer and locknut whenever maintenance performs an engine wash or VSV lube procedure. Because of the known high vibrations that the V2500 engines produce during operations; coupled with the constant movement of the Stator Vane Bleed ring; the connecting bolt at the VSV Actuator Fork End to the Stator Vane input rod would fall out within two flight cycles if the locknut was not installed. He noted again that the aircraft flew for thirty-one days after their sign-off without any VSV discrepancies.

Synopsis: An Aircraft Maintenance Technician (AMT) and an Aircraft Maintenance Inspector give their perspective as to why a locking nut that secures a VSV Actuator Fork End bolt to the Stator Vane Bellcrank input rod on a V2500 engine was found missing during an A-Check Inspection. The A321 flew 31-days without any VSV discrepancies on the right engine. Undocumented maintenance or sub-standard aircraft hardware are believed to be contributors.