A Mechanic and a Fixed Base Owner/Operator; with an Inspection Authorization (I/A) rating; report about inadequate Major Repairs they had performed on a Aero Twin Commander 690B aircraft. Damage was previously caused by a failure of the hydraulic actuator clevis fitting on the right Main Landing Gear (MLG).
Synopsis
A Mechanic and a Fixed Base Owner/Operator; with an Inspection Authorization (I/A) rating; report about inadequate Major Repairs they had performed on a Aero Twin Commander 690B aircraft. Damage was previously caused by a failure of the hydraulic actuator clevis fitting on the right Main Landing Gear (MLG).
Narrative
A Twin Commander 690B collapsed the right hand main landing gear in 2008. My employing Repair Station company recovered the plane from the runway. The damage was assessed and repairs were made. The damage was along the belly of the right side of the fuselage. This was a very large project. This was to be my first major repair project. We removed and repaired damage to the aircraft. The major repairs were done per Contracted Engineering drawings. The repairs were performed; inspected; tested and aircraft was returned to service.During the month of August 2010; the aircraft went to a pre-buy inspection at another facility. During inspection they found some discrepancies on the repairs we made needing re-work. These repairs included insufficient rivet edge distance on stringers and over bucked rivets. I was notified by my employer of the findings and informed that the re-work was to be done by another facility.This was my first and biggest major repair project. I realize the scope and detail of a project like this requires much more attention to detail. I need to request [increased] inspection by multiple inspectors on the work performed during and after repairs. This will assure better quality of work. I also need to inspect closer the work performed by myself and those assisting me. A project like this is too big for just one Inspector. My employer has notified its employees of new protocol to have even more attention to detail and scope of the jobs we perform.
Second reporter narrative
A Twin Commander 690B collapsed the right main gear on landing rollout. We recovered the aircraft from the runway. The aircraft was damaged along the right side of the belly from (Frame Station) F.S. 37 to F.S. 223. We commenced repairs on the aircraft and completed all repairs to return the aircraft to service. The Major Repairs such as the stringer splices and bulkhead repairs were done IAW (In Accordance With) Engineering instructions and drawings. Prior to re-skinning the aircraft and securing the floor [panels]; I inspected the mechanic's work for workmanship and conformity. The aircraft was re-skinned and the floor put back down. All repairs were performed outside the pressure vessel as the floor is the pressure vessel. The plane was pressurized and checked for leaks. The aircraft was test flown with no discrepancies. The logbooks were completed and FAA Form 337 was completed. A few months later; the aircraft went in for a pre-purchase inspection at another facility. During their inspection they found some discrepancies on the repairs we performed that needed re-work. These repairs included rivet Edge Distance (ED) requirements on stringers and several rivets which had been driven (bucked) too much during installation. After reviewing the photos I agreed with their findings. The repairs were made to the aircraft by that facility and I believe the aircraft has been released for service. After seeing the repairs that needed to be made I realized my Final Inspection of the aircraft before re-skinning was inadequate. I own an aviation company along with a partner and we inspect all work performed by the mechanics prior to returning aircraft to service. In this case however; I believe our policy should be amended. After discussing this oversight with my partner we have decided a job of this magnitude should require multiple inspections by two different inspectors as the repair scheme is too large for one set of eyes. We have implemented this new inspection criteria into our company policy.
NASA callback
Reporter stated the replaceable clevis that has been failing is attached to the Main Landing Gear (MLG) and also secures the main hydraulic actuator rod end to the same clevis. There is also an emergency actuator attached to a similar clevis on each main gear. Incidents of the right Main Gear collapsing have happened on landing; taxiing and turning off runways.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.