| 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. |
What happened
On 22 February 2018, a Piper PA-28R departed from a local aerodrome to travel to Sunshine Coast Airport, Queensland (Qld). The weather at the time included rain showers, low cloud and reduced visibility. Approaching the airport, the pilot progressively descended the aircraft to remain clear of cloud.
Air traffic control (ATC) advised the pilot that further adverse weather was approaching the airport and provided options to divert to a suitable landing area. The pilot elected to continue, arriving into the circuit at low level in deteriorating weather conditions.
ATC issued a ‘check gear down’ warning to the aircraft shortly before being unable to maintain visual contact with the aircraft in the circuit.[1] Air traffic controllers further issued a ‘Safety Alert, Terrain’[2] call as the aircraft manoeuvred to the north of the airport in the proximity of Mt Coolum (682ft). Air traffic control regained visual contact with the aircraft on short final.
The pilot reported that approaching the airport in the reduced visibility, he relied upon vertical visual contact with the ground to maintain his situational awareness when the horizontal visibility deteriorated. The pilot also stated that he was familiar with the local area and carried two Garmin GPS[3] and two iPads with planning and navigation software.
Figure 1: Sunshine Coast Airport proximity to Mt Coolum, Qld
Source: Google Earth Pro Image 31 October 2017 with ATSB annotations
Visual Meteorological Conditions (VMC) requirements
Table 1: VMC criteria for aeroplanes below 3,000ft above mean sea level
| Class of Airspace | Flight Visibility | Vertical and Horizontal distance from cloud | Conditions |
| Class G (Uncontrolled) or within 1,000 ft of ground | 5,000M | Clear of cloud and in sight of ground or water | Radio must be carried and used on the appropriate frequency |
| Class D (Controlled) | 5,000M |
600M horizontal 1,000FT vertically above cloud Or 500FT vertically below cloud |
ATC may permit operations in weather conditions that do not meet these criteria (Special VFR). |
Source: Aeronautical Information Publication (AIP) Australia: ENR 1.2-4 10 November 2016
Safety message
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 a safe outcome.
VFR[4] 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.
The ATSB SafetyWatch highlights the broad safety concerns that come out of our investigation findings and from the occurrence data reported to us by industry.
Flying with reduced visual cues and Inflight decision making such as in this occurrence remains one of the ATSB’s major safety concerns.
Number 4 in the Avoidable Accident series published by the ATSB titled ‘Accidents involving pilots in Instrument Meteorological Conditions’ lists three key messages for pilots:
- Avoiding deteriorating weather or IMC[5] requires thorough pre-flight planning, having alternate plans in case of an unexpected deterioration in the weather, and making timely decisions to turn back or divert.
- Pressing on into IMC conditions with no instrument rating carries a significant risk of severe spatial disorientation due to powerful and misleading orientation sensations in the absence of visual cues. Disorientation can affect any pilot, no matter what their level of experience.
- VFR pilots are encouraged to use a ‘personal minimums’ checklist to help control and manage flight risks through identifying risk factors that include marginal weather conditions.
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.
__________
- A standard path normally flown within 3nm (5.5 km) by aircraft when taking off and landing at an airport
- Air traffic control will issue a ‘Safety Alert, Terrain’ to aircraft, when they become aware that an aircraft is in a situation that is considered to place it in an unsafe proximity to terrain along its intended flight path
- Global Positioning System
- Visual Flight Rules
- Instrument meteorological conditions (IMC): weather conditions that require pilots to fly primarily by reference to instruments, and therefore under Instrument Flight Rules (IFR), rather than by outside visual reference. Typically, this means flying in cloud or limited visibility.