In late September 2009 gale-force winds hurled one of the biggest dust storms in recent memory across the eastern States of Australia, blotting the sky across most of NSW and causing havoc for any pilot unlucky enough to be caught up in the chaos.
I have a saying – “experience is what you get when you don’t get what you want”. In late September 2009 I had a great experience.
Peter, a good friend and fellow pilot, was to join me in my 2005 model Cirrus SR22 for a Cirrus Fly-In at Broken Hill. I had been looking at the weather map for at least a week knowing that a strong weather system was due to pass through the south of the state that day. We had planned to leave Wagga Wagga mid-afternoon.
I had studied the NAIPS forecast carefully that morning and was aware that blowing dust and severe turbulence up to 6000ft was forecast. I knew we would have a slow trip due to headwinds of up to 50 knots and a Sigmet was valid.
After a busy morning in the office and an unexpected visit from friends, just before leaving I downloaded the latest forecast and took a quick look to confirm that not much had changed. At the airport we grabbed a quick bite to eat prior to departure and quickly discussed the weather. I checked the radar for storms.
I have flown about 1800 hours since gaining my licence in 2004, with more than 200 hours IFR logged over the past three years. I have a CIR and a CPL and enjoy planning and flying IFR. I am particularly careful with thunderstorms and freezing levels and have from time to time made landings or delayed flights to avoid such weather.
I was concerned about the forecast for high-based thunderstorms with a freezing level of around 10,000ft, as this would keep us closer to the ground than might be ideal with the forecast blowing dust. I was happy enough to set off with this forecast, assuming that I would easily fly above the dust – it was forecast to 6000ft.
We headed off and kept initially to 6000ft to avoid some high-based storms. I did not want to fly into an embedded thunderstorm – my worst nightmare, and one Peter had recently experienced with his family.
After passing Griffith we cleared the storms and approached further mid-level cloud. I carry supplementary oxygen and often fly at FL 130-150 chasing smooth conditions or a good tailwind. However today, rather than climb to assess the conditions at a higher level, I continued on.
Flying into dust
Light dust soon changed into heavy dust, and the flight became quite uncomfortable. In the bumpy conditions I slowed up the plane and hand-flew – something I rarely do, given the exceptional autopilot fitted to the Cirrus. I normally fly at 8000-9000ft at LOP mixture settings but today I was flying ROP into a headwind of up to 60 knots.
During this time my friend and I had discussed many things (too many perhaps) and we dwelt on the performance of the engine in such a dusty environment.
I commented on how flimsy the foam air filter appeared on this 300hp engine. “Something that would suit a lawnmower”, I suggested! I also remembered the result of operating a tractor in extremely dusty conditions with a poorly fitting air-filter – a failed engine resulted! A blocked air filter was not good for engine performance.
Flying is all about decision making, which I greatly enjoy. It had become obvious that we would not fly through this storm as quickly as we had first thought – so we climbed to 10,000ft in an attempt to get out of the heavy dust – where we had been for more than 45 minutes. The conditions did not improve so we then decided to put down and wait it out and check the air filter. We diverted to Ivanhoe, which was about 40 minutes away, and called for the weather on the ground. To my surprise there was a METAR at Ivanhoe and the controller reported the essential information as, ‘Cloud 001 and visibility 1000, wind 25G40’. Based on this forecast I knew it would be difficult to get into Ivanhoe – the dust was obviously thick all the way down.
With the poor report for Ivanhoe, I radioed through to get a weather report from a RFDS flight heading for Broken Hill. The controller reported that he was just out of the dust at 12,000ft but in and out of cloud.
Based on this information I set track for Broken Hill and started climbing to 14,000ft to exit the dust and survey the situation. Our climb progressed well and I became slightly distracted organising the oxygen equipment. We both noticed a slight shudder in the engine. I was watching the OAT closely and had switched the de-ice system on. The last thing I needed was an iced plane. We were just edging out of the dust at 12,800ft but the OAT had now dropped to minus 2°C. The engine gave an almighty shudder and we lost power. We both assumed the worst – a blocked air filter!
Emergency
I quickly checked fuel and mixture, switches and throttle. Full throttle would not work. I switched the fuel pump to boost and continued to move the throttle. I found a steady, smooth running engine at about 30 per cent power. Peter urged me to make a PAN PAN call and head straight for Ivanhoe. My first instinct was to spend a few more seconds assessing the situation but instead I made the call and diverted for Ivanhoe again – time was of the essence.
Peter called for me to pull the Alternate Air and although this kept the engine running smoothly it did not allow me to develop full power. That confirmed my worst suspicion – a dusted motor. Obviously dirty air had taken its toll in this extreme environment.
I had now diverted all of my attention to making Ivanhoe and landing the plane in very poor conditions. I asked Peter to check the CMAX approach plate for Ivanhoe and was shocked to find that one did not exist. Ivanhoe is an unlicensed airport. Our only chance of landing suddenly became very risky.
I concentrated fully on assessing the rather diabolical situation. Here we were with partial power loss, in an extreme dust storm, heading for a runway where the conditions were way below minimas (if an IFR approach had existed). What to do?
We split tasks. Peter was to look up ERSA and help with navigation, I was to fly the plane and keep us in the air. I quickly established that I could only manage approximately 30 per cent power with a smooth running engine and that would get us to Ivanhoe. I also had to design an instrument approach to a runway that I had not landed at before. I knew the country was very flat and save for radio towers we should not hit anything on the way down.
I had also worked out (with the help of the Garmin VSR indicator) that we could arrive at the field at the right height and the right position to land. We figured we had one chance at landing with such a crippled engine. Peter informed me that with runway 34 we would be on heading for a straight in landing. He determined the strip was bitumen, 1200 metres long and had lights – thank goodness! I choose to keep slightly above ideal glide slope to conserve height but we needed to get to the ground for visibility.
We called an emergency and requested emergency services. I determined that 30-40 per cent power was still available – but would this remain? Every minute was precious. In case of not sighting ground, I had armed the Cirrus parachute and believed the lowest height for safe deployment was 2000ft (around 1700ft AGL). ATC now advised that the visibility on the ground was just 200 metres in blowing dust. The airport safety officer was on the ground and the lights had been activated. How were we to possibly land? Luckily, at 2000ft Peter called that he could make out the ground and we should be able to land.
When we became visual with the airfield we were approximately 150 metres off the centreline and I was able to quickly manoeuvre the plane to land in a 25 knot cross wind. The visibility was approximately 800 metres in the dust. It was darker than a moonless night. Not long after landing, visibility dropped to 200 metres.
I cancelled SAR through a Jetstar flight overhead that had been asked to circle by ATC and see us safely to the ground.
The aftermath
After being met by the local policeman who insisted on checking my driver’s licence, we were kindly transported to the local pub where we had a most memorable night. The locals were very friendly and keen to hear of our ordeal. Peter made friends by putting $100 on the bar, believing we had experienced a ‘near death’ situation. Of course, the locals were fully aware of our emergency as the airport officer had just sat down for his first beer when contacted by ATC. We soon found the Cirrus weekend had been cancelled as only four planes had arrived and many did not leave or turned around due to the poor conditions.
I spoke to my LAME early the next morning – he had two theories for the lost power. One was a fuel mixture that was too rich at altitude. I discounted this as I believed I had climbed at a full power setting of 20gph and knew this would not cause power loss at 13,000ft. The other theory was of ignition problems due to spark crossing leads in a highly static environment. I had not heard of this and believed it might be possible.
Back at the plane, I removed the dirty – but not blocked – air filter and conducted run ups to determine that the engine seemed okay. However, erring on the side of caution we were picked up by a friend, who incidentally conducts a lot of Angel Flights!
Peter flew my LAME and me back a few days later for a thorough check. After an hour or so we flew home.
What happened? As a test run to check out one of two theories, I climbed to 13,000ft on the homeward leg and overhead Griffith pushed the mixture knob to full rich. As to be expected the engine shuddered and lost power. But of course in my mind this could not have been the problem as I would never do such a thing!
With a Cirrus it is difficult to hide from mistakes. The engine data can be downloaded and replayed from the safety of your home PC. After some agonising scrutiny and replaying the flight several times there was only one conclusion that I could draw – 110 per cent pilot error! I had climbed from 6000ft to 12,800ft on a full rich mixture – losing power due to an over rich mixture.
How could this happen? Flying conditions were difficult and I was in ‘unfamiliar territory’ – ROP, hand-flying, heavy dust and turbulence. The mind can play strange games during high workloads. We had convinced ourselves that the engine would probably fail due to dust and when it lost power I remained fixed on this without adequate problem solving.
Lessons learnt
With the benefit of hindsight, what would I do differently?
- Make time to read forecasts carefully – especially when conditions are difficult. In re-reading the forecast it was obvious that the dust storm was more severe than I had thought and conditions at Broken Hill were below minimas when I left Wagga Wagga. I still would have left on that day, but would certainly have climbed higher at Griffith to fly above the dust storm if possible, or return if not. From close study of the forecast it was obvious that the dust storm covered a large area.
- Use the correct fuel settings for the altitude. Although this is obvious it can be easily overlooked in difficult situations.
- When flying with an experienced pilot, take care not to be complacent and take on undue risk. Never rely on an experienced pilot next to you to ‘save the day’. In challenging conditions – less talk more concentration for PIC. During this emergency I was extremely glad Peter was there to help – I doubt I would have landed without his input.
And during the emergency:
- Do not jump to conclusions. Things are not always what they seem. Read the checklist – there is one on the MFD and I carry a paper back-up but I did not refer to these. It calls for best fuel flow for the altitude – not full rich at all altitudes!
- Height buys time. At 13,000ft I had plenty of time to thoroughly check out the situation but did not take the time to adequately troubleshoot.
- Check the time to the nearest airport. As it turns out, Hay was much further (70nm compared with 38nm to Ivanhoe) but the same flying time due to the strong winds – up to 70 knots. And Hay has an instrument approach. This decision would have reduced the workload on descent, perhaps giving me time to re-assess the mixture and power settings.
- Continue to check all power and fuel settings on the descent. Once we made the decision to land I did not spend much more time attempting to regain power that I did not need for the descent. Re-gaining power would have reduced my anxiety caused by the marginal conditions.
- Double check runway headings and use the Garmin ‘Direct To’ button to re-align exactly with runway heading. We intersected the runway at approximately 15°, which made it difficult to see the runway in such poor visibility.
My experience has of course made me look forward to the new generation of FADEC engine systems.
Of course, there are a few positive outcomes. An engine will not choke in severe dust due to a blocked air filter (and will not lose power quickly). You could potentially fly for hours in dust without problems.
Having made the decision to land, I was able to calculate and accurately fly an instrument approach in marginal conditions and safely land.
And finally, as my wife said when hearing the story, “that experience will no doubt make you a much better pilot!”
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