Horizontal stabiliser bung design considerations
Date issue released
Safety Issue Description

The design of the horizontal stabiliser bungs did not consider aspects that would ensure the identification of an installed bung, or the safe operation of the aircraft if the bungs were not removed prior to flight.

Issue number
AO-2022-058-SI-02
Issue Status
Closed – Adequately addressed
Transport Function
Aviation: Air transport
Issue Owner
Regional Express Pty Ltd
Mode of Transport
Aviation
Issue Status Justification

By removing the horizontal stabiliser bungs from operational use, the operator has mitigated the risk of any adverse consequences attributed to their design or as a result of their use. As such there is no longer a safety issue.

Issue finalisation date
Recommendation
Action number
AO-2022-058-SR-24
Organisation
Regional Express Pty Ltd
Action date
Action Status
Released
Action description

The Australian Transport Safety Bureau recommends that Regional Express Pty Ltd further reviews the horizontal stabiliser bungs design and pre-flight procedures to ensure that installed bungs are readily identifiable and will not adversely affect the continued safe operation of the aircraft if not removed prior to flight.

Organisation Response
Date Received
Organisation
Regional Express Pty Ltd
Response Status
Response Text

While Rex accepts the safety recommendations in part, it is our contention that these recommendations do not comprehensively address the primary safety concern related to the initiation of a take-off roll with bird bungs installed. Specifically, Rex is focused on mitigating the risk associated with an aircraft commencing a take-off roll with bird bungs installed.



With this focus, Rex has undertaken a thorough review in response to the safety recommendations, evaluating the risk profile linked to bird nesting at the three airports—Cairns, Townsville, and Mt. Isa—where bird bungs were previously in operation. This comprehensive review aimed to assess the feasibility of implementing additional risk controls to minimise the likelihood of unidentified nesting occurrences at these locations. Additional risk controls include, but are not limited to:

  • Engineering support at applicable ports in the event that nests are identified; and
  • Introduction of a specific Maintenance Item (visual inspection) by engineers at each LC2 inspection (every 8 days) to identify and clear any FOD, including nesting material, from the elevator alcove area.



Following this review, the decision has been made to decommission the bird bungs in all 3 ports. This determination is fully endorsed by the Rex Safety Management Group and the Rex Board Safety and Risk Committee.



It is noteworthy that the practical testing of elevator movement with bird bungs installed was not conducted (to our knowledge) by the ATSB as part of their investigation. Rex has consulted SAAB in conjunction with carrying out appropriate testing, results of which further support the outcome of the internal review.

ATSB Response

By removing the horizontal stabiliser bungs from operational use, the operator has mitigated the risk of any adverse consequences attributed to their design or as a result of their use.

ATSB Response date