The Civil Aviation Safety Authority has provided an extension to the deadline for the completion of Cessna Supplemental Inspection Documents – or SIDs – on two groups of aircraft.

The extension applies to Cessna 100 series aircraft used in charter and aerial work and Cessna 200 series aircraft used in private operations.

SIDs compliance dates for both these operational categories have been extended by three months to 31 March 2016.

Originally the CASA compliance date was 31 December 2015.

The extension recognises the growing backlog of aircraft awaiting SIDs inspections at maintenance and repair organisations, particularly in rural regions where access to specialist technical staff is restricted.

This additional period also allows for reduced activity at CASA and in the aviation community associated with the Christmas holiday season.

The deadline for the completion of private category Cessna 100 series aircraft remains 30 June 2016.

SIDs inspections were developed jointly by Cessna and the United States Federal Aviation Administration due to concerns relating to potential corrosion and fatigue damage to principal structural elements of the aircraft.

In many cases these components, which are critical to the airworthiness of the aircraft, have not been inspected since the aircraft was manufactured many decades ago.

The SIDs program, which complements existing scheduled maintenance, requires the additional detailed inspection of a range of critical structures including wing spars, wing attachment points, wing struts attachments as well as horizontal and vertical stabiliser attachment points.

About 3,600 Cessna aircraft in Australia are covered by the SIDs program.