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.
On the afternoon of 9 July 2020, a Beechcraft A36 departed Lark Quarry in Central Queensland to conduct a private flight to Gympie, Queensland. There was a pilot and three passengers on board. The pilot received the en route weather forecast on the morning of departure, approximately 10 hours prior to the actual flight time due to lack of phone coverage in the area. The weather report at that point in time was suitable for a flight under VFR.
During the flight, the weather began to deteriorate closer to the coast as the aircraft neared its planned destination. The pilot observed increasing overcast cloud on the intended track and commenced a descent from 9,500 ft to remain clear of cloud. The aircraft levelled at 4,500 ft, which appeared to be well below the cloud base.
A short time later, the aircraft entered cloud and the pilot lost all visual references. The pilot immediately contacted air traffic control (ATC) and declared a PAN PAN to request assistance, while commencing a climbing turn onto a reciprocal heading. The climbing turn enabled the aircraft to regain VMC after about two minutes in cloud.
The pilot then conducted a diversion to Mundubbera, Queensland and was able to maintain VMC for the remainder of the flight.
Visual Meteorological Conditions (VMC) requirements
Figure 1: VMC criteria for aeroplanes in Class G airspace
Source: Aeronautical Information Publication (AIP) Australia: ENR 1.2-4 14 May 20
The pilot advised the ATSB that they had a pre-planned course of action for the situation of inadvertently flying into weather that was less than VMC. An important part of this plan was to immediately notify ATC of the situation to ensure all possible assistance was gained. The pilot committed to this plan and carried it out to effect a safe recovery.
Obtaining weather forecasts
The AIP ENR 1.10 Section 1.2.2 states:
Flights for which a forecast is required and cannot be obtained, are permitted to depart provided the pilot is satisfied that the weather at the departure point will permit the safe return of the flight within one hour of departure. The flight is permitted to continue if a suitable forecast is obtained for the intended destination within 30 minutes after departure.
Source: Visual Flight Rules Guide 14 May 20
If the pre-flight briefing is obtained more than one hour before the flight, the pilot should obtain an update before departure to ensure that the latest information available can be used for the flight.
Pilots can obtain forecasts and updates by radio en route if other forms of communication are unavailable.
Obtaining the latest valid weather forecasts during the pre-flight planning phase is paramount to the safe conduct of a longer-distance VFR flight. Pilots are encouraged to make conservative decisions when considering how forecast weather may affect their flight. If poor weather is encountered en route, timely and conservative decision-making may be critical to ensuring a safe outcome.
VFR pilots are also encouraged to familiarise themselves with the definition of VMC criteria and carefully consider available options where forecast or actual conditions are such that continued flight in VMC cannot be assured.
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.
- Visual flight rules (VFR): a set of regulations that permit a pilot to operate an aircraft only in weather conditions generally clear enough to allow the pilot to see where the aircraft is going.
- PAN PAN: an internationally recognised radio call announcing an urgency condition which concerns the safety of an aircraft or its occupants but where the flight crew does not require immediate assistance.
- Visual Meteorological Conditions (VMC): an aviation flight category in which visual flight rules (VFR) flight is permitted – that is, conditions in which pilots have sufficient visibility to fly the aircraft while maintaining visual separation from terrain and other aircraft.