Day 15 - Lesson 11

Steep Level Turns

Posted by Owain Abraham-Williams on Sunday 20th September 2015

My lesson was booked for 9am, but the weather wasn’t looking great. I checked the METAR and my suspicions were confirmed, I didn’t expect to be flying today. Derek then called to say that although the weather wasn’t good enough this morning, the forecast was for it to improve later in the day, so my lesson was put back to 3pm.

When I arrive at the flying club, Derek telephones the tower to ask if I can do some circuits, but they are too busy and won’t allow it. Next Derek phones Cardiff to see if we can go there, but because of the Rugby World Cup, they’re also too busy. So Derek suggests we can fly to Kemble and do circuits there, with a bit of map reading on the way. I went out to do the pre-flight checks while Derek filled in the paperwork.

Derek soon joins me and says he doesn’t think there’ll be enough time to get to Kemble, fly some circuits and get home before sun-set. So instead Derek starts plotting a course on his map while I complete the check lists; he tells me we’ll just do some map reading. We taxi and take off, then fly towards Cheddar Reservoir. As we’re leaving Bristol ATZ Derek says he’s changed his mind again and instead we’ll learn about steep turns!

In a normal turn you bank the wings at about 30°, a steep turn is when you bank the wings as far as 60°. Derek explains the manoeuvre and tells me that with the wings banked so steeply the aeroplane can’t maintain it’s lift, so you have to pull back on the control column to adjust the elevators if you don’t want to descend. I am also reminded that the stall speed will be higher than normal while in the turn, so I must add a little throttle after passing 30°.

Derek demonstrates a right-hand turn at 45°, then he asks me to have a go, turning left this time. I roll onto a normal 30° turn; once established and flying steadily left I add a little more power and turn to 45°. At this angle I am much lower on the horizon than when flying at 30°, and I also have to maintain quite a lot of back pressure on the control column to stop us from descending. After flying in a complete circle I level the wings, reduce the throttle but forget to let go of all the back pressure, so we start climbing a little. Derek explains what I did wrong and we’re soon back flying straight and level. We try it again, turning right this time and straight into a 45° turn without holding at 30° first. Derek is pleased with my control.

After this Derek demonstrates a 60° turn, this is really an incredibly tight turn and I can feel the G-forces as we go round. Then it’s my turn. I start banking the wings, and as we pass 30° I apply some throttle and pull back on the control column to maintain our altitude. At 60° the back pressure is actually hard to maintain, you have to be reasonably strong to hold this for extended amounts of time. When I roll out of the turn I am quite disorientated, not quite sure if I’m flying south away from the airfield, or north towards it. It takes me a few moments to get my bearings.

After all that excitement it’s time to head back to the airport. Derek says I should do a FREDA check, I look at him blankly and he says to look at my check list. Here it is:

  • Fuel - On with sufficient quantity
  • Radio/Nav. Aids - Tuned to right frequencies and ATIS obtained
  • Engine - Temperatures, pressures, mixture and carburettor icing checked
  • Directional Indicator - Synchronised with the compass
  • Altimeter - QNH/QFE set as required

It was the fourth item on this list (Directional Indicator, or D.I.) that Derek specifically wanted me to focus on. The D.I. works by spinning a gyroscope; as the aeroplane moves it can introduce a gimbal error, known as drift. After many steep turns both left and right, the drift was a lot and the D.I. was out by tens of degrees (I forget exactly how much it was out, but it was huge, if we’d been flying by the D.I. alone we would have been going in the totally wrong direction.) Fixing this is simple, just re-align the D.I. with the compass. There’s a dial on the bottom left corner of the instrument exactly for this purpose.

As we approach the airfield and join downwind it’s time to do the BUMPFFICH checks (Brakes, Undercarriage, Mixture, Pitch, Fuel, Fuel pump, Instruments, Carburettor heat and Hatches and harnesses). My landing wasn’t as good as last week, but it was okay. Hopefully next lesson I’ll be back on circuits and can hone those landing skills.