Technical assistance to CASA in the examination of a cracked Cessna 402C wing attach fitting

The ATSB has completed examination of the JRA-445-1 wing attachment fitting supplied by the Civil Aviation Safety Authority (CASA). In addition, an original Cessna wing attachment fitting (part no. 0811350-10), also supplied by CASA, was examined for comparison of the material properties and manufacturing methodology. A report detailing the examinations and findings was prepared and provided to CASA on 28 September 2016.

For further information regarding the wing fittings or airworthiness bulletin AWB 57-015, please contact CASA on 131 757 or www.casa.gov.au.

Updated: 30 June 2016

During an inspection of the wing attachment fittings of a Cessna 402C in accordance with Civil Aviation Safety Authority (CASA) airworthiness directive AD/CESSNA 400/92, a crack was identified in the inboard lower attachment fitting (Figure 1). The cracked attachment fitting (part number JRA‑445‑1) was manufactured by J&R Aerospace as a replacement for the original Cessna fitting.

Figure 1: Cessna 402C lower inboard wing main spar attachment fitting showing an approximate 100 mm (4 inch) crack (indicated by orange arrow)

AD/CESSNA 400/92 specified inspection of the outboard attachment fittings, but not the inboard fittings. Compliance with the airworthiness directive was required prior to the component exceeding 5,000 hours time in service. The cracked JRA‑445‑1 fitting had accumulated 2,831 flight hours time in service.

On 17 June 2016, CASA issued airworthiness bulletin AWB 57‑015 to alert operators and maintainers of Cessna 400 series aircraft of premature cracking in a Cessna 402C wing attachment fitting manufactured by J&R Aerospace.

As part of their investigation, CASA requested the technical assistance of the Australian Transport Safety Bureau (ATSB) to conduct a metallurgical examination of the cracked fitting.To facilitate this assistance, the ATSB initiated an external investigation under the provisions of the Transport Safety Investigation Act 2003.