master steep turns by instruments


fc-cover-photo-smMastering steep turns by reference to instruments is a common pilot training challenge. Presumably you have already mastered flying steep turns by visual reference (VR). (See my post, “fly better steep turns.”) Similar technique is required for doing them by instrument reference (IR), except that now you must obviously draw all your cues from the instrument panel.

As with every IR maneuver, your scan for steep turns should focus primarily on the attitude indicator, backed up by the altimeter, heading indicator, and/or other required instruments.* That’s because so long as you hold constant attitude, other instrument movements will remain very predictable. But once your attitude begins fluctuating, successfully chasing all the rest becomes impossible. (For more on proper instrument scan, see my post, “IFR made easier…“)

For VR steep turns, you stabilized pitch and bank angles using the horizon and your cowl out the windshield. Well, trick #1 on IR turns is to establish similar references using the attitude indicator. Sure, the 45º angle is easy enough to see on the instrument, but the trick here is to precisely nail the pitch indication too — that means using the attitude indicator as a quantitative instrument, not just qualitatively as you would VR.

For those without a flight director, start with a simple “calibration” exercise. Stabilize your aircraft in a steep turn (use outside cues if necessary, or have your CFI fly the aircraft) and note the EXACT pitch location of the central dot on your attitude indicator. Is it one dot thickness above the horizon line? Or perhaps halfway between the horizon line and the first pitch reference line above it? It should be no surprise that with the same power setting under otherwise similar conditions, placing that central dot in the same place every time will consistently establish you in the correct pitch attitude, or very close to it. The attitude indicator is far more accurate in pitch than most people realize − you can indeed hold “half-a-dot” pitch accuracy or better with good results.

Okay, now that your scan is nailed and your attitude indicator calibrated, here’s my recommended sequence for steep turns by instrument reference, with #2 and #3 most likely being your key items to improve upon:

1. Note your starting heading and set power. (If possible, use the same power setting every time.)

2. Roll PROMPTLY into the steep turn using the attitude indicator to establish your 45º bank, and center the slip-skid ball with rudder. IMPORTANT: As you roll through 30° add power and back pressure to nail that pitch dot precisely where you calibrated it.

3. Okay, here’s the big secret to both visual- and instrument-reference steep turns. Once established in the turn, MAKE PITCH CHANGES ONLY; DO NOT TURN THE YOKE LEFT OR RIGHT! (except as necessary to correct for turbulence). This is important because every time you change bank angle in steep turns, you’re changing the pitch attitude and back-pressure required to maintain altitude. So turning the yoke once established in the turn adds the need for pitch adjustment, in addition to the need to correct the bank angle. By pitching and turning you’ve got two variables working at the same time, and you’re all too familiar with the result — oscillating all over the sky! So once established in the turn, DO NOT TURN THE YOKE — ADJUST PITCH ONLY, to maintain altitude; you’ll be delighted at how much easier the maneuver is.

4. When you see your target roll-out heading approaching on the heading indicator, begin a prompt rollout 20-25º ** before reaching your desired heading, using the attitude indicator to level the wings. IMPORTANT: Reduce power and release back pressure as you roll through 30 degrees. If you begin rollout at the correct instant, your heading will be right on when you level the wings.

Voila! Perfect steep turn! ©2009 Gregory N. Brown

* If your aircraft is equipped with an IVSI (instantaneous vertical speed indicator) that should be a major part of your steep-turn scan − just keep the IVSI needle “in the doughnut” (centered within the zero numeral), and your altitude will remain constant.

** The rollout rule of thumb is to start leveling the wings at ½ your degrees of bank angle before reaching your target heading. So for a 45º bank start rolling out 22.5º before reaching your target heading. In a 60º bank, start rollout 30º before reaching your target heading.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: