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Notice published: 21 August 2018

Discontinuation notice

Section 21 (2) of the Transport Safety Investigation Act 2003 (TSI Act) empowers the Australian Transport Safety Bureau (ATSB) to discontinue an investigation into a transport safety matter at any time. Section 21 (3) of the TSI Act requires the ATSB to publish a statement setting out the reasons for discontinuing an investigation.

On 06 April 2018, the ATSB commenced an investigation into a Terrain Awareness and Warning System (TAWS) warning and missed approach involving a Beechcraft B200, VH-FDW, near Gladstone Airport, Queensland, on 5 April 2018.

During the conduct of the area navigation (RNAV) approach for runway 10 the pilot received a ‘Terrain, Terrain, Pull up’ warning. As the aircraft was in instrument metrological conditions (IMC), the pilot responded in accordance with standard operating procedure. Only a single warning presented and the pilot climbed the aircraft to an appropriate safe altitude. At that point, the aircraft was no longer in IMC and the pilot conducted a visual approach, landing without further incident.

The ATSB obtained additional information from the operator that identified the TAWS warning received as a nuisance alert. The aircraft was not in danger of impact with terrain and was safely established on the RNAV runway 10 profile. The operator had known about nuisance alerts on this approach since it was amended in 2010, when the final track was aligned over high ground near Mt Larcom. Other operators also experienced nuisance alerts in the same location.

The operator had implemented use of the TAWS flap override function to prevent nuisance alerts specifically for the Gladstone RNAV runway 10 approach. Before implementing this procedure, the operator consulted with the TAWS manufacturer and conducted a flight validation. On this occurrence, the pilot forgot to select flap override.

At the time of publishing, Airservices Australia had completed a draft revised RNAV runway 10 approach for Gladstone that was runway aligned and not over the high terrain leading to the nuisance TAWS alerts. While still requiring a flight validation, this new approach should eliminate the nuisance TAWS alerts.

The ATSB reviewed the information relating to this occurrence as well as information relating to previous TAWS occurrences involving the RNAV runway 10 at Gladstone. Based on this review, the ATSB considered it was very unlikely that further investigation would identify any systemic safety issues. Consequently, the ATSB has discontinued this investigation, but will continue to monitor TAWS occurrences involving all operators.

The information contained in this web update is released in accordance with section 25 of the Transport Safety Investigation Act 2003 and is derived from the initial investigation of the occurrence. Readers are cautioned that new evidence will become available as the investigation progresses that will enhance the ATSB's understanding of the accident as outlined in this web update. As such, no analysis or findings are included in this update.

General details
Date: 05 April 2018 Investigation status: Discontinued 
Time: 0900 EST  
Location   (show map):Gladstone Airport Investigation type: Occurrence Investigation 
State: Queensland Occurrence type: E/GPWS warning 
Release date: 21 August 2018 Occurrence class: Operational 
Report status: Discontinued Occurrence category: Incident 
 Highest injury level: None 
Aircraft details
Aircraft manufacturer: Raytheon Aircraft Company 
Aircraft model: B200 King Air  
Aircraft registration: VH-FDW 
Serial number: BB-1880 
Operator: Royal Flying Doctor Service of Australia (Qld Section) Ltd 
Type of operation: Aerial Work 
Sector: Turboprop 
Damage to aircraft: Nil 
Departure point:Brisbane, Qld
Destination:Gladstone, Qld
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Last update 14 November 2018