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| A left-hand (anti-clockwise) circuit. Diagram courtesy Rdhuhamel via Wikipedia. |
The instructor flew the first circuit, climbing on the upwind leg. I followed through as he turned to the crosswind leg and levelled off at 1000 feet. He must have reduced the throttle too, from climb to cruise power, but I didn't notice right away. I was remembering how it felt the first time I flew. I felt a lot more comfortable with the plane's movements this time, but levelling from the steep climb still made me jump a little.
The crosswind leg was simple and smooth, but in no time at all it was time to turn again, onto the downwind leg. Now we were flying straight and level. We could see the runway off to the right-hand side, parallel to our course. I continued to follow through on the controls, and soon we were "abeam the upwind end of the runway": that is, with the runway markings in line with our wing. At this point the instructor prompted me again to make the next standard radio call:
"Golf India Zulu, downwind for touch and go."
"Golf India Zulu, roger, report final."
A touch and go is where you come in as if to land, touch down on the runway, and then when you're satisfied that the landing was good and you could stop, open the throttle again and take off again right away, if you still have enough runway. It's commonplace when you're flying circuits for practice, so it's good to let the tower know which you plan to do, so they can plan other aircraft movements. Of course, if it goes wrong, you might end up landing anyway, or going around (aborting the landing and flying another circuit).
In another minute or so, we had flown the length of the runway, and with it at our five-o'clock, we turned again, onto the base leg. Like the crosswind leg, this would be very short, and we started our descent almost immediately. The instructor throttled back a lot, and then dropped the nose (by pushing the stick forward a little) so that we would maintain the gliding airspeed by losing height. There was a reasonable wind down the runway, so as it turned out, he misjudged the rate of descent, and by the time we turned again onto the final leg, he had to add a little more power so that we'd make it over the aerodrome fence.
The controls are a lot softer or looser in the glide. With the engine idling, there's less airflow over the ailerons, and at the lower speed, there's less airflow over all the control surfaces, so you need a bigger stick movement for the same effect. At the same time, you can judge much smaller movements of the aircraft, because the ground is increasingly close, so you make much finer adjustments to keep yourself over the runway centreline. These two factors mean that the normal tiny movements of the stick to continually adjust and correct your attitude become much larger movements, looking (from inside the cockpit) almost as if you're out of control. It was time for the next radio call.
"Golf India Zulu, final for touch and go."
"Golf India Zulu, runway 05 grass cleared for landing. Surface wind 035 degrees 8 knots."
"Clear to land runway 05 grass, Golf India Zulu."
This confirmed to us (and of course I had to read back, to check) that there was nothing (aircraft, vehicles, or personnel) on the runway, and the tower had reserved it for our use, so it was safe to us for land. You don't always get cleared to land right away: often the tower will ask you to continue approach, usually because the aircraft ahead is still on the runway and they're waiting for it to vacate the runway. Most aircraft at Cambridge use the tarmac runway, not the grass one, so Tiger Moths don't often have to wait for a clearance.
I continued to follow through as the instructor came in to land. From the rear cockpit I couldn't always see the runway, but he'd warned me to line up a landmark on the horizon that was in line with the runway. There's a convenient and recognisable formation of trees past the end of 05 grass, so I was able to gauge our positioning by looking up at those.
We touched down, and rolled along the grass enough to slow down, but quickly sped up again and soon we were once again airborne. This time was to be more exciting: as soon as we were established in the climb, the instructor handed over control to me.
When you learn to fly, one of the quite early lessons is simply on flying straight and level. Once you've mastered the manoeuvre of not manoeuvring, you take another lesson to learn to climb at a desired rate (also starting the climb and levelling off from the climb), to descend at a desired rate, and to turn to a given heading. Because of the weather, and the unusual circumstances of this lesson, I haven't learned any of those things yet. The circuit requires you to do all of them, seguing from a climb to level flight to descent in the space of a few minutes, while also turning during the climb and again during the descent. This was going to be quite a challenge for me.
First, I had to maintain the correct airspeed during the climb-out. We already had climb power set on the throttle from take-off, so I just had to keep the nose up, judging it not by our angle but by our airspeed. I'm still a bit too gingerly about changing the attitude of the aircraft, so I was too flat and the speed kept creeping up, resulting in a slow rate of climb. Normally, once the correct climb attitude is established, you then set the elevator trim, so you can keep the nose up without having to keep pulling the stick back. I never quite managed to get it stable enough to trim, though.
At the same time, I had to keep the wings level. You'd usually judge that by the horizon, both in front of you and by looking left and right along the wings. The clouds and haze meant there wasn't much of a horizon, but I didn't find it hard to judge based on the "seat of the pants" feel and what ground we could see.
Soon, we were coming up to 1000 feet and had to leave the climb. APT is the mnemonic for doing this: attitude, power, trim. I lowered the nose to cruise attitude (i.e. with the aircraft horizontal), and reduced the throttle to cruise power. The throttle lever is only a couple of inches long, and it is directly connected to the engine, so it can be quite fiddly to get to just the right level. By the time I'd got the engine to 1950 rpm and got us stable at the right height, I'd forgotten to adjust the trim, and it was already time to turn onto downwind.
I pushed the stick to the right to roll the aircraft, initiating the turn. A few seconds later, I noticed I was being pressed to one side, like a car going round a roundabout. I remembered I had to use the rudder to keep the aircraft "balanced", so that we'd turn. I think I did a pretty good job of keeping a 30° bank angle, but again, it's quite hard to tell without a horizon.
The downwind leg should have been the simplest. As the longest leg, I had more time to get the aircraft in trim, and all I had to do was fly straight and level, and make the radio call again. But with the elevator trim still too far back, the aircraft had a noticeable tendency to rise. I didn't always react correctly to the situation: if the airspeed was too high and we were descending, I would sometimes react by pushing the stick further forward before realising I should do the opposite. If you were watching you could be forgiven for thinking I was trying to work out how to fly as I was going along, instead of already understanding the controls. There's just a large gap of practice in between understanding on a whiteboard and being able to react correctly in the air without thinking.
All the same, I thought I was doing well, until the instructor told me to look at where the runway was. I looked to the right, and the line of the runway was a good 20° from our heading. I had let our course drift gradually to the left.
Another right turn later, and we were on the extra-long base leg. The instructor took control quite early to start the descent: perhaps he wanted a second attempt at judging the rate of descent correctly. After the turn onto final, it was time for the radio again.
"Golf India Zulu, final for touch and go."
"Golf India Zulu, continue approach."
"Continue, Golf India Zulu."
This meant the runway wasn't yet clear for us, but they expected it to be clear in time to land. This might happen if another aircraft is already taking off on that runway, which doesn't happen often for us: although Cambridge is quite a busy airport, most people prefer the main concrete runway instead of the parallel grass runway.
If the runway wasn't clear soon enough, we would have to climb away from the runway and go around, but a few seconds later, the tower cleared us again. The approach was perfect this time, and we touched down just as planned and took off again after a short ground run.
The third circuit followed the pattern of the ones before, but it was a lot smoother. When we were abeam the runway end again, I made a different call:
"Golf India Zulu, downwind for landing."
"Golf India Zulu, report final."
"Wilco, Golf India Zulu."
This time we would land fully and taxi back in. But right now I had to concentrate on the downwind leg, and I managed to fly parallel to the runway this time. The turn to base was spot-on, and this time the instructor wanted me to start the descent and approach. To start descending, the mnemonic is PAT: power, attitude, trim. First I reduced the throttle to idle and let our airspeed reduce to the 65 mph glide speed. Then I pitched the aircraft forward, so that we would maintain that speed by descending. I'm not yet experienced enough to judge the approach for landing, so the instructor kept telling me how to adjust our descent angle to keep us at the correct rate of descent.
While concentrating on adjusting our descent, I also had to make the turn onto final and get lined up with the runway. As before, I could hardly see the runway from the rear cockpit, even when leaning as far out as the harness would let me. When I could see the runway on either side, that told me I had drifted over and needed to correct my course.
This time, I only just had time to call final and obtain landing clearance before we heard another pilot on the radio: a Cityflyer twin-engine jet on a long, straight-in approach. It was coming in to practise using the aerodrome's ILS. I'll describe that another time; for now, just know that it meant the large jet was coming straight for the main runway, in the opposite direction to us (i.e. on runway 23 main). He was still a long way from the aerodrome: ILS approaches can often start 10 miles out or more. I felt relieved and a little smug when the tower warned him off because of a Tiger Moth on final for runway 05 grass.
A few seconds later, it was time for the instructor to take control again and land us. I took control again to taxi back in, and unlike the taxi out it was a race against time: if we didn't cross the main runway before the big jet was on final approach, the tower would keep us on the taxiway until it finished landing. We made it back in time, and I finished taxing back to the hangar.
In the end, I'd had a really exciting flight. The instructor had warned me at the start that I might feel I did much worse than my previous lesson, because there was so much to do at once. He warned me not to become disheartened. But while I knew I'd struggled to co-ordinate everything today, I felt I'd done well. On top of that, I was really positive to have managed another flight after a long Winter of cancellations. Roll on the Spring and clear skies!
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