Narrative:

I was tasked with the final installation inspection of the number nine slat. After performing an inspection; prior to installation; of surrounding structure; I okay-ed the 'clearance to install' the slat. While the slat installation progressed; I gave attention to another inspection task taking place simultaneously for a possible turnover that I would eventually be working. When I was called upon to complete the final installation inspection I verified the correct installation paperwork was being used; subsequent torques were applied; and then proceeded to inspect the security of installation and operational checks of the slat. I did not observe at that time any obvious defects.[one week later] it was brought to my attention that [same aircraft] was in for maintenance due to a slat asymmetry issue. Also; that the outboard auxiliary slat track was damaged and two main slat tracks bushings were missing. Irregularities to the outboard auxiliary slat track were not present during the final inspection and operational checks; and the absence of main tracks were not obvious during final inspection and operational checks; possibly because of surrounding structure and associated attached hardware that may have been blocking my viewpoint. The possibility of oversight may have been a contributing factor; as I was not present to witness the entire installation process step by step as a result of another inspection task taking place at the same time. There was at no time external pressure placed upon me to perform multiple inspection tasks at the same time; and the decision to do so was of my own volunteer.with jobs of this complexity; inspectors must be present to observe all steps and procedures throughout the entire installation process. I feel a step by step signoff may have helped to prevent this incident.

Related reports:

Google
 

Original NASA ASRS Text

Title: B767-300 Maintenance Inspector reported that a slat failed due to an asymmetry issue; a week after he inspected the installation of the same slat.

Narrative: I was tasked with the final installation inspection of the number nine slat. After performing an inspection; prior to installation; of surrounding structure; I okay-ed the 'clearance to install' the slat. While the slat installation progressed; I gave attention to another inspection task taking place simultaneously for a possible turnover that I would eventually be working. When I was called upon to complete the final installation inspection I verified the correct installation paperwork was being used; subsequent torques were applied; and then proceeded to inspect the security of installation and operational checks of the slat. I did not observe at that time any obvious defects.[One week later] it was brought to my attention that [same aircraft] was in for maintenance due to a slat asymmetry issue. Also; that the outboard auxiliary slat track was damaged and two main slat tracks bushings were missing. Irregularities to the outboard auxiliary slat track were not present during the final inspection and operational checks; and the absence of main tracks were not obvious during final inspection and operational checks; possibly because of surrounding structure and associated attached hardware that may have been blocking my viewpoint. The possibility of oversight may have been a contributing factor; as I was not present to witness the entire installation process step by step as a result of another inspection task taking place at the same time. There was at no time external pressure placed upon me to perform multiple inspection tasks at the same time; and the decision to do so was of my own volunteer.With jobs of this complexity; inspectors must be present to observe all steps and procedures throughout the entire installation process. I feel a step by step signoff may have helped to prevent this incident.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.