Pressurisation failure — Saab 340B, regional route

Summary

A Rex Airlines Saab 340B experienced an uncommanded cabin pressurisation loss while cruising at FL180 en route from Adelaide to Port Lincoln. The flight crew initiated an emergency descent and diverted to Adelaide Airport. All 20 passengers and 3 crew were uninjured.

Investigation Findings (4)

1. 01A fractured pressurisation outflow valve actuator rod was identified as the cause.
2. 02The actuator was within its scheduled replacement interval but showed evidence of corrosion damage accelerated by exposure to moisture.
3. 03Rex Airlines reviewed maintenance procedures for pressurisation system components to include a corrosion check.
4. 04CASA subsequently issued a Service Difficulty Report on the component for tracking across the Saab 340 fleet.