30 October 2002
Transport Canada has received a Service Difficulty Report (SDR) that erroneous torque values were indicated while installing the wing attach bolts on a Beech (Raytheon) E-90 aircraft in accordance with the manufacturer's instructions.
The special "pre-load indicating" washer indicated proper torque, when in fact the torque reached was approximately 30% of the specified value. Fortunately, this maintainer, through many years of experience pertaining to this particular task, recognized the discrepancy and identified the pre-load washer as being faulty.
The SDR database contains at least three similar occurrences.
Less experienced person(s) completing this task may not recognize the failure to reach the specified torque value. This could lead to the aircraft being returned to service in an unsafe condition.
To prevent further occurrences of this nature Transport Canada strongly recommends that persons be aware of the possibility of a false torque indication when completing this task.
It is imperative that the manufacturer's instructions be strictly adhered to; any discrepancies noticed during the procedure must be fully resolved prior to the return of aircraft to service.
Any defects or further occurrences of this nature are to be reported to Transport Canada, Continuing Airworthiness, Ottawa via the Service Difficulty Reporting program.
For further information, contact a Transport Canada Centre, or Mr. Paul Jones, Continuing Airworthiness, Ottawa, telephone (613) 952-4431, facsimile (613) 996-9178 or e-mail firstname.lastname@example.org.
For Director, Aircraft Certification
Chief, Continuing Airworthiness