VFR in not-so VMC weather

6039
Cessna 172

Name withheld by request

After lengthy pre-flight planning and preparation, a fellow CPL student and I left Parafield for our commercial training navex to Ayers Rock, via Coober Pedy and Alice Springs. Having recently achieved our PPLs, we were brimming with confidence and ignorant to the dangers that lay ahead in Central Australia.

After a long day of flying through Leigh Creek and Olympic Dam, I, as pilot-in-command (PIC), was keen to arrive in Coober Pedy. I held an ETA approximately 20 minutes before last light. With no GPS or DME, and sparse ‘1 in 60’ groundspeed checkpoints, we were heavily relying on heading and time—something that became all too meaningful to us as we crossed featureless terrain into a setting sun. Within a few minutes of the ETA, Coober Pedy appeared and we positioned for an over-top join from the dead side of runway 04.

After a pleasant and restful stay-over in Coober Pedy, we were up bright and early for our departure to Alice Springs. Despite great hospitality, there were limited facilities in the hostel, which meant flight planning on the bed with charts sprawled out in every direction and viewing the ARFOR on a smartphone with 3G wi-fi. With the planning complete, we boarded the hostel bus for the 12-minute transfer to ‘Coober Pedy International Airport’. We relished the opportunity to show off the stripes and play big-shot regional pilots, albeit in our C172R. We loaded the luggage, kicked the tyres and lit the fires. We were off on day 2 of our big cross-country nav.

Three hours across red, soporific terrain yet again; this time with familiar Class D procedures at the other end. We were asked to join downwind runway 12 and with a light easterly, we touched down and vacated efficiently at taxiway ‘C’ for GA parking. Taxiing past a RAAF Challenger was definitely a highlight I will remember forever! Officially ending my time as pilot in command, I was glad to be able to stretch my legs and clear my head inside the terminal. As I returned, the aeroplane was refuelled, the new PIC was ready to go, so off we went, blissfully unaware of what was to come.

The Alice weather was almost CAVOK, but as we crossed the MacDonnell Ranges to the southwest we started to realise the weather ahead was changing. I asked the pilot flying for his weather briefing and it looked OK; just some lower cloud at 3000ft associated with scattered showers. Then something reminded me; the cloud in an ARFOR is AMSL, not AGL. The cloud ahead was actually forecast between 500 and 1000ft AGL taking the elevation into consideration. As this realisation started to sink in, we both glanced behind us. Sure enough, the weather had closed us in. The moist air must have pushed against the ranges and cooled (my instructor said it might!) Damn. We were stuck. We pressed on, but now in the knowledge that the conditions were less than ideal.

Forty-five minutes into the one-and-a-half-hour journey to Australia’s red centre, we had descended to a mere 3000ft AMSL (1000ft AGL) and were still marginally VMC. The weather was becoming worse; and we had no choice but to follow the automatic direction finding (ADF), the only nav instrument on board, to Ayers Rock. As the cloud base lowered, so did we. We were now an estimated 400 feet off the deck. We knew we couldn’t descend any lower, but at 400ft, our tail was dragging in the cloud and, occasionally, so were we.

How did the conditions deteriorate so quickly? How did we get into this mess? With our combined instrument flying experience of eight hours, the prognosis wasn’t good. I’d read somewhere that the life expectancy of a VFR pilot in IMC was less than 180 seconds. The PIC muttered the words ‘If I need to, I’ll fly on the instruments.’ It was at this moment I became terrified.

‘Melbourne Centre, pan-pan, pan-pan, pan-pan, ABC, ABC, ABC, do you read?’

No answer.

‘Melbourne Centre, Melbourne Centre, ABC, do you copy?’

Nothing.

After what felt like two hours (it was five minutes), a scratchy transmission returned.

‘ABC, ABC, Melbourne Centre.’

Finally! Some help!

‘ABC is between Alice Springs and Ayers Rock very low level due cloud, do you have us on radar?’

Of course they didn’t, but it was worth a shot. I will always remember the conversation with ATC from this point.’

ML CEN: ‘ABC, are you aware of your exact location?”

ABC: ‘Negative. We left Alice Springs at 46 and estimate we have 26 minutes to run.’

ML CEN: ‘Are you VMC?’

ABC: ‘No.’

ML CEN: ‘VMC is a legal term. Are you visual with terrain?’

ABC: ‘Yes.’

ML CEN: ‘I’ve checked with the airport manager at Ayers Rock. Apparently the airport is non-VMC. There is an aerodrome to your right that you could divert to.’

ABC: ‘Roger. We have an ADF on board and so will continue to Ayers Rock.’

ML CEN: ‘Copy. What is your aircraft type, and how many POB?’

I thought to myself, there’s generally only one reason an air traffic controller wants to know this! He’s starting a safety report for our inevitable demise!

ABC: ‘Cessna 172 Cutlass, two POB.’

ML CEN: ‘OK. I’d like you to keep in touch. I’ll call again in one-five minutes. Good luck.’

Feeling deflated about ATC and uncertain about what was ahead, I can say without doubt that the next 20-30 minutes were the most frightening moments I have had in an aeroplane. My WAC still has my right-thumb print in the bottom right corner. It’s funny what you remember of these situations, but I recall gazing out the right window for suitable landing sites, while scanning the fixed card ADF, time and WAC chart. I repeated the ETA over and over in my mind like a mantra and revised the calculation about four hundred times. I checked the directional gyro (DG) and compass just as many times to make sure it hadn’t precessed—putting us on another track inbound, and one that could have had us closing on a giant rock at two miles per minute.

Equally, I hoped the ADF hadn’t failed and left us with a false straight-ahead indication. A quick check of the Morse code ident revealed the ADF could still be trusted. ‘Good; at least we have a functional navaid to keep us on track!’ I said. Just as soon as the last dash-dot could be heard on the ADF, the runway came into view in the lower left windscreen. ‘I think that’s it!’ the PIC shrieked. Even if it wasn’t Ayers Rock, it was a bitumen strip and we were going to put her down!

Holding our fears at bay, we now had to ensure a safe landing on an almost-flooded strip. I had developed a fear that the PIC was about to rip the throttle back and bank hard left to join final approach. I made a strong recommendation that we join upwind at a relaxed pace to ensure we set up appropriately for landing.

What eventuated was a stable approach to a landing firm enough to let us know we had arrived. As we taxied into the GA parking and tied the aeroplane down, the only words spoken were those on the CTAF to advise we had vacated the active runway. Neither of us was ready to debrief just yet. As we passed through the terminal, we learned that three recent RPT aircraft (QF, VO, JQ) had diverted to their alternate (Alice Springs) after not getting visual.

We were stranded in the territory for the next four days under torrential rain; an extremely rare weather event!

I’ve had more than enough time to debrief personally on this event and there are a number of opportunities for learning. It was a frightening experience, but one that has allowed me to teach my students the importance of pre-flight planning and always having an ‘out’. My top lessons that came from this experience are:

  1. Be aware of the plan and have a back up, even if you’re not the pilot flying
  2. Don’t just read the weather, understand what is happening
  3. Trust your instruments
  4. Trust HDG and time

Above all, these situations can be avoided and it is so important to consider the weather at the destination. If the weather deteriorates, make early decisions and turn back before it is too late. As a qualified flight instructor now, this is the advice I give my students when I (reluctantly) authorise them for their long solo nav.

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