| Occurrence Briefs are concise reports that detail the facts surrounding a transport safety occurrence, as received in the initial notification and any follow-up enquiries. They provide an opportunity to share safety messages in the absence of an investigation. Because occurrence briefs are not investigations under the Transport Safety Investigation Act 2003, the information in them is de-identified. |
What happened
At about 1000 local time on 6 December 2024, a Leonardo Helicopters AW139, departed Bankstown Airport, New South Wales, on a visual flight rules (VFR) flight to respond to a search and rescue incident at Bondi Beach. The weather was clear departing from the airport, however on arrival at the scene, and at about 500 ft above mean sea level, a thin layer of fog was present. After the rescue operation was conducted using the helicopter’s rescue winch, the helicopter was requested to land at a pre-arranged site north of Bondi. In preparation for landing, the crew opened and secured the left side door. As the helicopter continued in a northerly direction, the weather deteriorated and the landing at the arranged site was no longer possible. To avoid the worsening weather, the pilot turned the aircraft eastward over the ocean toward clear skies. During this time, the crew planned for another landing site at the Sydney Children’s Hospital, however, as they continued in an easterly direction, the fog thickened considerably, and the pilot unintentionally entered instrument meteorological conditions (IMC). The pilot momentarily lost perception so added power and used the autopilot to climb to 1,000 ft where they became clear of cloud and visual.
The recorded flight data indicated that the helicopter maintained a climb rate of approximately 1,000 ft per minute with a 5° nose-up attitude. Between 400–500 ft, the pitch attitude gradually reduced to a nose-down attitude of 3° momentarily, resulting in a temporary reduction in the rate of climb to 500–600 ft per minute. The helicopter resumed a 5° nose-up attitude and continued climbing at a rate of approximately 1,000 feet per minute. This sequence occurred gradually over 10 seconds.
The helicopter continued to climb to 1,500 ft. At about this time, the pilot remembered the left side door was still open and realised that the 80-knot maximum airspeed limit had been exceeded while they were in IMC. The pilot immediately reduced the airspeed and the crew closed the door. After landing and shutting down at the hospital helipad, the helicopter was secured and taken out of service for a maintenance inspection to ensure airworthiness. The crew returned to base by alternate transport.
Safety message
The ATSB encourages all pilots, no matter what their experience levels, to develop the knowledge and skills required to avoid unintentional operations in IMC. This includes having alternate plans in case of unexpected changes in weather, and making timely decisions to turn back, divert or hold in an area of clear weather. The use of a ‘personal minimums’ checklist can also be a strong mitigator against the risk of flying into bad weather. Checklists can help pilots more clearly identify risk factors.
To increase the chances of safely recovering from an inadvertent entry into IMC, VFR pilots are encouraged undertake recovery training and basic instrument flying competency checks during their operator proficiency checks or other training.
ATSB booklet Accidents involving Visual Flight Rules pilots in Instrument Meteorological Conditions (AR-2011-050) provides for guidance on avoiding VFR into adverse weather. Further specific information for helicopter pilots is also available on the ATSB website.
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 to produce a short summary report and allow for greater industry awareness of potential safety issues and possible safety actions.