Survey of Aviation Maintenance Technical Manuals, Phase 3 Report: Final Report and Recommendations

This report contains the results from the final phase of a three-phase research effort. Phase 1 of this research effort surveyed the procedures used by five aircraft manufacturers to develop maintenance documentation. Several potential human factors issues were identified in the processes used by these manufacturers to develop their maintenance manuals. The issues included the reactive rather than proactive use of user evaluations, the limited use of user input and procedure validation, no systematic attempts to track errors, and the lack of standards for measuring document quality. In Phase 2, a written survey was used to solicit information about user perception of errors in current manuals, manual usage rates, and general manual quality. On-site interviews of technicians were also conducted to gather feedback about the types of problems encountered with manuals, the associated impact, and suggestions for improving manuals. Feedback was obtained from technicians responsible for maintenance on a wide variety of Title 14 Code of Federal Regulations Part 25 aircraft. Survey results revealed that, although user evaluations of the accuracy and quality of technical manuals are generally good, they rate manuals as having poor usability. Comparing the results of Phase 1 to the Phase 2 survey results supports the need for a higher level of user involvement during the document development process. In this report, a series of recommendations are outlined to address problem areas identified in Phases 1 and 2. It is recommended that (1) manufacturers and operators improve communication between technicians submitting change requests and technical writers to ensure prompt feedback of actions, (2) maintenance procedures be validated using standard human factors techniques, (3) the industry cooperate in the development of a system akin to MSG-3 for identifying maintenance procedures that should be systematically validated, and (4) manufacturers maintain databases with a history of user-reported errors, feedback to the user, and actions taken. By tracking the history of user error reports, manufacturers can then validate maintenance procedures that have the greatest potential impact on safety or economics. Finally, an example is described (using the MSG-3 process) of how these recommendations may be implemented