9 - Stalling over Oxfordshire
Monday, May 21st, 2007Hours on this day: 1h 0m
Hours so far: 12h 30m
Today, I had my first lesson back at PFT in Oxford, after returning from Jerez yesterday. The weather looked overcast and threatening, but in fact the cloud was few (very few) at 3500 ft, overcast at 5000 ft, and the wind was 10 knots close to the runway - quite benign conditions. So after a thorough briefing (quite a contrast with some of the FIS instructors!), I went out to re-acquaint myself with a PA28. How different everything seems now, compared to my first lesson here a week last Friday! There is a faint but unmistakable sense of familiarity starting to emerge. Following the walk-around, we taxyed out on the grass for runway 03, and followed the power checks from the checklist. All very straightforward.
Takeoff in a PA28 on grass is rather different to a C172 on 2000m of tarmac. A rotate speed of 65 knots is chosen to give plenty of safety margin, so the elevator control on takeoff is a balance between unweighting the nosewheel to prevent the bumpy grass from hammering it too hard, and preventing the aircraft from rotating airborne before the desired airspeed has arrived. I followed the instructor through on the new technique, but it seems fairly simple. Once airborne, the instructor promptly handed me control, and the interesting process began of applying my newfound skills to the novel environment of the PA28. The controls seemed a bit more responsive, but perhaps it was just the different geometries and response rates leading to that impression: general wisdom is that the Cessna 172 is a bit more responsive than a PA28.
I made a reasonable job of maintaining the trimmed 75 knot climb to the target altitude of 3500 ft, whereupon we made some turns to position ourselves for a stalling exercise. For the level cruise, power of 2350 rpm is applied, and trim for level flight results in about 95 knots. Visibility was good, and with a few stray wisps of cloud around our altitude, my well-coordinated turns with a panoramic spread of Oxfordshire at 30 degrees across the windshield as we skimmed wisps of cloud reminded me what an absolute joy it is to be flying. I found that I was starting to make automatic rudder control and balance adjustments, from visual detection of tiny yaw changes in my peripheral vision - which given the mystery and difficulty which obscured the use of the rudder just a few days ago, was very pleasing indeed. The instructor never once pointed out a lack of balance to me.
The aim of the lesson was stalling, in a variety of configurations: clean with no power, with 1700 rpm and with 1200 rpm, then with flaps 25 at the glide and at 1500 rpm, and finally with flaps 25, 1500 rpm and a 30-degree turn: the latter to simulate a grossly-mishandled turn to final. It’s much easier to perform the standard stall recovery in a graceful and co-ordinated manner in a PA28 than in a Cessna 172, especially with flaps deployed, because the application of full throttle does not hurl the nose skywards as it does in the Cessna. I assume it’s because the thrust line is more closely aligned with the centre of drag in a PA28. I’m starting to understand why my instructor in Jerez expressed a preference for the PA28 over the Cessna, citing the Cessna’s pendular stability.
I felt my recoveries were OK if a little uncoordinated, but the instructor was very happy with them. The crucial point is that adding power reduces the stall speed and height loss, and adding flap also has a similar effect. Stalling with power and flap allows the best recovery performance, with only about 100 feet of height loss. My control of the pitch and yaw attitude is moderately instinctive now, regardless of the aircraft configuration. The stall in the turn was much more benign than I expected: I was expecting a hefty wing drop, but the aircraft just maintained its angle of bank and pitched downwards. Recovery was simple indeed, with little rudder needed.
My big weakness at the moment is attention to detail in the checks. For example, I kept forgetting to add carb heat before stalling, and remove it after. I forgot to raise the 25-degree flaps after the final stall in the turn, and I didn’t notice until the instructor pointed it out to me, half-way back to Oxford. The instructor didn’t make a big deal of it, but I think it’s a really serious matter: too many AAIB reports indicate carburettor icing as the cause of premature death. More generally, I keep on omitting things from checks. I need to find a way of methodically improving my attention to detail. This doesn’t come naturally to me.
I brought us into an accurately-flown 75-knot glide descent, to join right downwind for 03. Salient features of the local area and circuit were shown - particular care is needed to avoid Weston-on-the-Green. Parachute zones rightly have zero tolerance of airspace incursions. Established in the downwind, checks were made - I need to learn these - then we turned base just beyond Yarnton, and configured the aircraft for a 75 knot descent at 1800 rpm with flaps 25. Turned final, and maintained the approach accurately with little difficulty. It seems that all the practice in Jerez of approach flying at precise speed and altitude in bumpy air has handsomely paid off: tight speed control with elevators/trim and descent control with throttle is almost second nature. At about 100 ft from the runway, a sharp downdraft caught us, and the instructor took control to land - handing it back to me to taxi us over the grass and park.
This was a profoundly satisfying lesson, because it demonstrated the huge development of my skills achieved in Jerez. I feel almost like a different person now. The next lesson is the circuit: which I expect will be a substantial challenge, and I just can’t wait!