Aviation occurrence briefs

Loss of hydraulic pressure involving OAS Parts LLC UH1H, 41 km WNW of Warnervale, Boree Valley, NSW, on 1 February 2018

Status: Completed
Investigation completed


If a transport safety occurrence does not warrant an investigation under the Transport Safety Investigation Act 2003, the ATSB can produce an Occurrence Brief — a one-page factual summary of the event that provides an opportunity for industry participants to learn from reported occurrences in the absence of an investigation.

What happened

On 1 February 2018, at about 1535 Eastern Daylight-savings Time (EDT), an OAS Parts LLC UH-1H helicopter was conducting fire control operations when the pilot noticed a strong smell of oil in the cockpit and oil droplets hitting the water, under the helicopter, in a dam. The pilot manoeuvred the helicopter to a paddock close by for a precautionary landing. In the last metre or so of landing, the hydraulic warning light indicated a loss of hydraulic pressure and the controls stiffened up during the last positioning movements onto the ground. The pilot was able to land the helicopter without incident. On landing, the hydraulic oil was diminished with an empty hydraulic tank and the belly of the aircraft was covered in oil.

On inspection it was found that two hydraulic lines had rubbed together causing one to split. Engineers replaced a hose that had been injected by the adjacent hose causing a hole. Both hoses and the hydraulic pump were also replaced as per the maintenance manual.

Safety message

Emergency situations can rapidly develop from initial signs and symptoms to a complete failure. The proactive response of the pilot to the initial signs of this malfunction enabled the helicopter to be manoeuvred into a much safer position by the time the full failure occurred.

About this report

Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.

General details
Date: 01 February 2018   Investigation status: Completed  
Time: 1535 EDT    
Location   (show map): 41 km WWN of Warnervale (ALA), Boree Valley    
State: New South Wales    
Release Date: 12 April 2018   Occurrence category: Incident  
Report status: Final   Highest injury level: None  

Aircraft details

Aircraft details
Aircraft model OAS Parts LLC, UH-1H  
Type of operation Aerial Work  
Sector Helicopter  
Damage to aircraft Nil  
Last update 04 June 2018