Failures in inspection procedures: case studies
Department of Metallurgy and Materials Engineering, Institute of Materials Science, University of Connecticut, Storrs, CT, USA Received 1 July 2002; accepted 21 May 2003
The most frequently used inspection methods, i.e., visual examination, dye penetrant examination, magnetic particle examination, eddy current examination, and ultrasonic examination, are, for the most part, eﬀective and reliable. There have been instances, however, particularly in the aviation ﬁeld, where the designated methods of inspection were not able to detect cracks, and as a result catastrophic failures occurred. In the aviation ﬁeld, when major-accidents occur there is usually a thorough investigation to determine the cause. We are fortunate the accident reports concerning such events are made public, so that engineers can learn from the mistakes which led to an accident and take corrective action to prevent a recurrence of such accidents. The present paper discusses a number of cases wherein faulty inspection procedures resulted in accidents. These cases are based upon published reports as well as personal experiences, and will deal with the crashes which involved: a 707 freighter (visual examination), a DC-10 (dye penetrant), a small passenger plane (magnetic particle), a 737 (eddy currents), and a 747 freighter (ultrasonics). # 2003 Elsevier Ltd. All rights reserved.
Keywords: Inspection procedures; Visual inspection; Dye penetrant inspection; Magnetic particle inspection; Fatigue
An important purpose of a failure analysis is to discover shortcomings in design, material selection and inspection procedures in order to prevent a recurrence of the type of failure under investigation. To reach this goal it is necessary that the results of a failure analysis be made available to as wide an audience of concerned designers and inspectors as possible, and this conference helps to do just that. It is also fortunate that many major disasters, particularly in the aircraft ﬁeld, have been thoroughly investigated and the ﬁndings published. On the other hand it is unfortunate that the circumstances surrounding many failures in the industrial sector and in product liability cases are not publicized, with the result that these failures often recur. This paper will focus on the shortcomings of inspection methods, in the hope that a greater awareness of these limitations will lead to improved structural performance in the future. The cases to be discussed will be drawn fromthe aviation ﬁeld, but the lessons involved have general applicability.
* Corresponding author. Tel.: +1-860-486-2941; fax: +1-860-486-4745. E-mail address: email@example.com (A.J. McEvily).
1350-6307/$ - see front matter # 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.engfailanal.2003.05.004
168A.J. McEvily / Engineering Failure Analysis 11 (2004) 167-176
2.1.A problem with visual inspection
On 14 May 1977 at 09:33 a Boeing 707-321C cargo plane, G-BEPB, operated by Dan Air crashed in good weather near Lusaka International Airport in Zambia with the loss of six lives. The aircraft had seen a total of 47,621 airframe hours and a total of 16,723 landings, 16,285 of which having occurred while the plane was in passenger service with Pan Am. The accident was caused by the in-ﬂight separation of the right hand horizontal stabilizer and elevator of the tail assembly. Examination of the wreckage indicated that the cause of failure was a fatigue crack which had originated at a rivet hole in the top chord of the rear spar of the horizontal...