Aviation safety investigations & reports

TAWS warning and missed approach, involving a Beechcraft B200, VH-FDW, near Gladstone Airport, Queensland, on 5 April 2018

Investigation number:
AO-2018-029
Status: Discontinued

Discountinued

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.

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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   Investigation level: Defined - click for an explanation of investigation levels  
Location   (show map): Gladstone Airport    
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 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  
Last update 03 December 2018