In May this year I was flying my Vans RV7A from Forrest to Kalgoorlie, with another pilot. We were heading to my home airport, Jandakot, after the Australian light aircraft championships in Cessnock, NSW. I had flown this route several times.
The forecast weather enroute and at Kalgoorlie was for excellent flying conditions. I filed an IFR plan, tracking from Forrest to Rawlinna, Coonana and Kalgoorlie at 8,000 feet. The route would keep us over the transcontinental railway line which has numerous airstrips along the way that might be useful in an emergency. The flight level would also help ensure we remain in VHF contact with Melbourne Centre as far as possible. My aircraft does not have a HF radio.
Our planned ETA for Kalgoorlie was 0617 UTC. At the time of our departure, the Kalgoorlie TAF was showing:
TAF YPKG 272303Z 2800/2900 36006KT CAVOK
FM280200 27012KT CAVOK
FM280700 29012KT 9999 SHOWERS OF LIGHT RAIN NSC
There was no Inter, Tempo or Prob. However, I was also aware of a cold front hitting the WA coast, bringing stormy weather to Perth. While we had originally intended to continue onto Jandakot after refuelling at Kalgoorlie, we were resigned to the fact that this might not be possible and we would be spending the night in Kalgoorlie.
We departed Forrest at approximately 0330Z. The flying conditions were excellent and there was a jovial mood in the cockpit as we recalled our war stories from Cessnock. But the mood rapidly changed.
Shortly after reporting overhead Coonana which to the best of my recollection was approximately 0435Z, Melbourne Centre broadcast a SIGMET for squally thunderstorms valid from 0454Z to 0700Z. The squall line was heading directly between my position and Kalgoorlie.
I was rapidly running out of options and struggling to keep the aircraft straight and level
Centre made a point of contacting me to ensure I had understood the SIGMET and break the bad news that thunderstorms had developed over Kalgoorlie.
After considering the options, I asked Centre to determine if a diversion to Leonora, about 120 nm to the north of Kalgoorlie, would allow me to avoid the squall line. They verified that an immediate diversion could work and so I amended my flight plan and set a heading for Leonora.
At this stage I had about 2 hours endurance including reserves and was hand flying the aircraft, working hard to stay on track, as conditions had suddenly become very turbulent with showers all around us.
I asked Centre for the weather at Leonora. I could tell immediately when the controller spoke that things were about to get much worse – there was now a PROzB 30 for thunderstorms there and another aircraft also reported thunderstorm activity heading for that airport.
It became apparent to me that our north-west track to Leonora was probably taking us into the squall line as it moved south-east (and probably more quickly than originally anticipated). I was rapidly running out of options and struggling to keep the aircraft straight and level.
The mood in the cockpit was now very sombre as our options were becoming very limited.
A voice in my head (probably because of attending numerous CASA safety briefings) told me that the best course of action in these circumstances was to get the aircraft on the ground ASAP. I asked my copilot to check the map for the nearest airfield. Fortunately, he quickly determined Carosue Dam was the closest, about 25 nm from our position and slightly east of our track. I immediately set a heading for Carosue Dam, conveyed my intentions to land to Melbourne Centre and amended my flight plan once again. At this stage, we were quite prepared to spend the night in the aircraft rather than continue flying in the conditions we were in.
Carosue Dam was a welcome sight and after overflying to determine the wind direction, we safely landed, much to our relief and that of Centre – and to the surprise of the airport manager!
Once on the ground, it became apparent we would not be going any further that day. A weather alert had been issued to the mine site for storms and lighting strikes, which materialised over the coming hours.
Fortunately, Carosue Dam is a gold mine with 450 FIFO workers. They generously made the camp facilities available, so we had a good meal and night’s sleep. We made the trek to Kalgoorlie the next morning in good spirits.
Lessons learnt
- Have a plan B even if you think you don’t need it. While I had reviewed the weather at Forrest and determined it was good flying conditions, I made no proper consideration for the cold front that was over Perth and moving inland. I should have mentally noted that squalls often develop ahead of a cold front and sorted out a plan B while safely on the ground.
- Seek the assistance of ATC, a terrific resource when things turn sour. The duty controller was offering all the assistance he could by getting weather updates from other aircraft and essentially living the experience with us. I could hear the disappointment in his voice when conveying all the bad news and then the relief when we landed at Carosue Dam.
- Make a precautionary landing your priority. The decision to land ASAP was probably the best one in my 870 hours of flying. When I first set course for Leonora, I didn’t have a clear mental picture of how widespread the squall line was or even its precise location; pressing on could have resulted in a much worse outcome.
