Tuesday, April 1, 2008

Nav 3, Take 1

Nav3 is a navigation exercise where the student pilot needs to convince the instructor of his ability to navigate solo in non-controlled airspace. This is a requirement for moving on to Nav4 which, precisely, is a solo nav in non-controlled airspace. In our case, this means departing Redcliffe properly, finding our way around, not getting lost, getting un-lost after simulating getting lost and performing diversions. All that without busting controlled airspace.

It is on the first leg of the nav, from Redcliffe to Esk, that the student needs to get a tick in all the right boxes. The portion of the flight after that is a supervised navigation exercise through Class C airspace (Oakey), uncontrolled airspace (Gayndah) and finally Class D airspace (Maroochydore).

We departed the circuit on downwind and stayed at the circuit height of 1000ft until we crossed the Bruce Highway. Then we started to climb gradually so as to remain under the steps of the overlying Class C airspace.

I knew from studying the map prior to the flight that our track intersected the limit of the 2500ft CTA step over the top end of Lake Samsonvale. However, instead of overflying it as expected, I found the lake was a couple of miles to my left. We were only 10 miles from Redcliffe, so that was some very significant drift. I checked the alignment of compass and DJ, which was fine. My suspicion was a stronger than expected south-easterly wind. I was about to do a 1-in-60 to compute a new heading to Esk when Mal said not to bother at that stage and keep flying our current heading.

We climbed to 3500ft, cleared the D’Aguilar Ranges, changed area frequency and kept climbing to 4500ft. Ahead of us was Lake Wivenhoe. Next task was to find the township of Esk.

The lake didn’t look at all like what I was expecting to see given where I thought I was. What I could see was a river and not a lake, which meant I was a lot further north than I should be. I tried to match the shape of the river bends with the map. This didn’t work, so I tried something else. There was a fairly large mountain ahead of me, which I thought was Mount Brisbane. This would actually make sense since the drift that pushed me north of Lake Samsonvale a few minutes ago would have pushed me in a similar manner to the north of Lake Wivenhoe.

However, a few things didn’t add up. I couldn’t see the bridges at the foot of Mount Brisbane or the township next to the substation. And there was a township on the edge of the lake under my left wing that didn’t match anything on the map.

Then it dawned on me (with a subtle hint from Mal: “What have we been suffering from in Queensland these last four years?”) that it was the drought that was responsible for the shape of the lake not matching the map. There was no magical drift or 50-knot crosswind to blow me off track. It all suddenly made sense. I was actually on track, the township on the left was Bryden and the mountain ahead of me was Mount Esk. Yey! And of course this also explained not having overflown the northern tip of Lake Samsonvale earlier. Order was restored to the universe.

I could further identify Esk because it was sitting to the south-west of Mount Esk in a dip between three hills. My last doubts were lifted when I saw the red rooves of the hospital in the south-west corner of the town, which matched exactly what I had seen in Google Earth at home a few days before when preparing for that nav.

Big sigh at that stage. The first leg of the nav was completed successfully, we found Esk and didn’t bust controlled airspace. I don’t think I came very far from failing though. All throughout this first leg I was verbalising out loud what was going through my head. Mal actually recommended to not make strong statements about where I thought I was, but rather start each sentence with “I think” which indicates to the instructor that you are still thinking and that there’s still a chance you may get it right in the end. It’s a bit like using legal language to prevent litigation.

After Esk we tracked to the south-west to find Perseverance Creek Dam, which is one of the VFR entry points for the Oakey RAAF base. When I had finished taking the ATIS, I noticed a lake ahead of us. No longer trusting the shape of lakes on the map, I was pretty sure this was Perseverance Creek Reservoir. I could even see the dam!

There was another lake, Cressbrook Reservoir, that we should have seen before this one, but this is a fairly mountainous country, with lakes tending to hide behind hills, so I was not overly concerned that I couldn’t see any other lake behind us. In addition, the map doesn’t show a dam for Cressbrook Reservoir, so this had to be the right one.

I was wrong on this one (again!), and Mal explained that I could have easily avoided that by using my watch for estimating where I should be now, rather then reading from ground to map (bad!). And looking at the VTC carefully, there is actually a dam for Cressbrook Reservoir, it is just very difficult to see because it is hidden under three thick coloured lines that represent the boundaries of class E and C airspaces and a danger area.

We obtained a clearance for Oakey, got handed over to approach and then tower. My radio calls went OK given that it was my first encounter with Class C airspace procedures. The preferred runway was 09, but we accepted runway 14 because it made the taxi to the civil terminal easier and provided us with an opportunity to practice crosswind landings.

The approach and touchdown went OK, even though my circuit was way too wide. On final I had the help of the PAPI lighting to stay on the glide slope. Very convenient. Compared to the 152, the heavier 172 is a lot more stable on final, which really helps. Soon after touchdown Mal had to jump on the yoke and turn the ailerons into the wind because I had forgotten about that last part of the crosswind landing procedure and the wind could have flipped the aircraft over… not good.

We parked at the civil terminal, had a peek inside the Museum of Australian Army Flying and took this picture of this Australian designed and built CAC Boomerang. It was donated to the museum by the widow of a former RAAF pilot who had flown the aircraft. Hopefully one day I’ll come back with enough time to visit the museum.

We departed Oakey for Kingaroy but didn’t quite make it to Kingaroy. The cloud base ahead of us was a lot lower and darker than forecasted, and it was obvious that heavy rain was falling on our expected track to Gayndah. Mal decided to not push forward and get back to Redcliffe instead. This gave me an opportunity to do a diversion. We turned east and passed abeam the Tarong Power Station.

We didn’t know if we would be able to cross the ranges, but we had a number of options. One option was to fly back via Kilcoy which would offer us lower ground. Or fly down the valley that leads to Watts Bridge and land there. And we still had the option of turning around and landing at Kingaroy.

We ended up going via Kilcoy, the clouds over the ranges giving us sufficient ground clearance. From there we followed the D’Aguilar Highway to Woodford, after which we descended to 1500ft and tracked direct to Redcliffe. We landed and debriefed. Mal asked me to concentrate on my readbacks the next time I fly in controlled airspace, and also make sure my maps are folded properly before the flight so that they can be neatly unfolded as the flight progresses. This is because at some point in the flight I had to take out the VTC for Oakey and the cabin was hardly wide enough for unfolding the map and folding it back properly. Which of course blocked the view and subsequently makes it very hard to "see", let alone "avoid".

Mal was very helpful in finding a spot in the busy booking sheet of the areo club for me to finish Nav3. He could make it fit in the day before my planned Nav4, which was great since it wouldn't mess up my training plans. The idea for the second half of Nav3 was to go to Gympie, then Maroochydore and back to Redcliffe. And after that, Nav4, first solo nav!

No comments: