The Australian Transport Safety Board (ATSB) has highlighted confusion over maintenance regulations after a Cessna 210 experienced control issues near Bourke in 2011.
VH-JHF was being flown on low-level aerial survey work when it hit some turbulence. Immediately afterward, the pilot experienced difficulties with elevator control inputs. The aircraft landed safely with no injuries to crew reported.
The ATSB found that the horizontal stabliser rear attachment brackets had broken, which caused the control issues. Fatigue cracks were also found in the forward spar.
During the investigation into the incident, the ATSB found that the aircraft has been maintained under CASA's generic Schedule 5 maintenance program, but that there was confusion in the industry that led operators to believe that this exempted them from complying with Supplemental Inspection Documents (SIDs).
A Cessna SID had been released mandating inspections "to find damage from fatigue, overload or corrosion through the use of the Non-destructive Inspections (NDI) and visual inspections." VH-JHF had had visual inspection done as per Schedule 5 only 30 flight hours before the incident with no defects detected.
"The Australian Civil Aviation Regulations 1988 (CAR) were being misinterpreted by some class B aircraft registration holders, to the extent that they believed that their aircraft was exempt from the manufacturer’s supplemental inspections when their aircraft was maintained using the CASA maintenance schedule," the report states.
"While the CASA maintenance schedule did not make any specific reference to the incorporation of the manufacturer’s supplemental inspections, it was a CAR requirement that all aircraft be maintained in accordance with approved maintenance data that, by definition, included those inspections."
The ATSB also found a safety issue with CASA allowing Schedule 5 maintenance when a more appropriate manufacturer's schedule exists, and stated that the CARs on the matter lack clarity.
The full report can be downloaded from the ATSB website here.