Date: 201401
Location: ZZZ.Airport, US
Aircraft: B767-300 and 300 ER
Operator: Air Carrier
Operating under: Part 121
Flight phase: Parked
Aircraft component: Trailing Edge Flap
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Technician
Reporter qualification: Maintenance Airframe; Maintenance Powerplant
Human factors: Situational Awareness; Confusion; Communication Breakdown; Training / Qualification
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Maintenance
When detected: Other During Maintenance
Result: General Maintenance Action
Contributing factors: Aircraft; Company Policy; Human Factors; Manuals; Procedure
Primary problem: Human Factors

Narrative: Received a call on [Hangar] Dock-6 to look at a delamination (delam) on the Outboard (O/B) flap on left wing. Tapped checked; located a delam on old repair and one more [area]. We have two delams at this time on a Chem-milled panel. The Composite Shop cannot duplicate conditions [used] in our home shop to apply bond primer per the Boeing Corporation Repair Manual [on the flap] in the hangar. So we had dock mechanics pull flap and send to Composite Shop. Supervision then started asking different Shops if they can repair 'On-Wing'. The Paint and Fiberglass Shop decided they would accept the job with the help of a Lead Mechanic. In the General Procedures Manual (GPM); it has certain steps to accomplish [the application of Bond Primer] with the aid of Quality Assurance (Q/A) to follow; IAW the GPM. None of the steps were taken with QA involved. The process of applying bond primer cannot be accomplished [properly] 'On-Wing' in the hangar. Material verification was bypassed and material removal [verification] was bypassed. At no time were Q/A involved in the repair process. You have to have access the back side of flap panel to bag during hot bond cure and to Tap Check. Hangar dock did not want to pull and send to shop. [Recommended] to pull [flap] part and send to shop.

Callback: Reporter stated their Composite Shop has humidity and temperature controlled environment that cannot be duplicated out on the hangar floor. The bond primer is difficult to use in the hangar which is not a dry environment. The Outboard (O/B) flap has an aluminum honeycomb core with internal doublers under the external flap skin that the honeycomb core is also bonded to during the cure process. Verification by Inspection of the internal bond cannot be accomplished on the Hangar Docks because Maintenance Management does not want to take the time to open the external skin of the flap to verify internal doubler bonding with the honeycomb core. The flap skin thickness varies from a thin .032' thousandths of an inch in the middle part of the flap skin panes to .125' thousandths at the panel edges.Reporter stated he refused to sign-off the hangar flap repair as a Permanent Repair because the conditions required to properly perform the bond repair noted in the Boeing Repair Manual were not changed. He made the repair a Temporary Repair that requires a Re-inspect every 3;500 hours and a Tap Check.



Synopsis: A Composite Shop Aircraft Maintenance Technician (AMT) reports why he refused to sign-off an Outboard Flap skin delamination of the aluminum honeycomb core as a Permanent Repair after the Bond Repair was accomplished in an uncontrolled Hangar environment.