Common errors

Instrument turn errors split into three families: bank angle errors (over- or under-banking for standard rate), altitude management errors (load factor mismanagement under hood), and rollout precision errors (anticipation timing). The six below cover the common faults.

1. Over-banking — turn rate above standard

What it looks like: the turn coordinator shows more than standard rate; the airplane is rotating heading faster than 3°/sec.

Why: the pilot banked aggressively at the roll-in, exceeding the calculated bank angle for the airspeed.

Fix: calculate the bank angle before the maneuver: TAS ÷ 10 + 7. Roll in to the calculated bank; verify on the turn coordinator. If above standard rate, reduce bank until the rate is correct.

2. Under-banking — turn rate below standard

What it looks like: the turn coordinator shows less than standard rate; the airplane is taking longer than two minutes for 360°.

Why: roll-in stopped at a shallow bank, or the pilot is unconsciously rolling back out partway through.

Fix: standard rate first, then verify on the HI. The turn coordinator is the primary feedback for bank rate — if it shows less than standard, increase bank.

3. Altitude loss in the turn

What it looks like: during the turn, altimeter unwinds 50–100 ft. Load factor not anticipated; back pressure insufficient.

Why: same physics as the steep turn altitude bust (V.A.ERR #1) — without the visual horizon, the cue is the altimeter, which moves after the airplane has already sunk.

Fix: anticipate the back pressure at roll-in. The bank-with-load-factor relationship is the same as a steep turn, just at smaller bank. Add back pressure as you roll in; trim after stabilizing.

4. Late rollout — overshoot the target heading

What it looks like: the pilot waits for the HI to show the target heading before starting the rollout. The airplane continues turning during the rollout and overshoots by 5–10°.

Why: treating the rollout as reactive instead of anticipated. The half-the-bank-angle rule isn't being applied.

Fix: lead by half the bank angle. At 17° bank, start the rollout when the HI shows ~8° before target. Practice the calculation until it's automatic.

5. Early rollout — undershoot the target heading

What it looks like: the airplane is wings-level 5–15° short of the target heading. The pilot is now flying straight in the wrong direction and has to re-enter the turn.

Why: anticipation too aggressive — leading by more than half the bank angle. Common in pilots who've been burned by overshoot errors and overcorrect.

Fix: measure the lead; don't over-correct. Half the bank angle is the rule. If the actual outcome is undershooting, the lead estimate was too aggressive — back it off slightly next time.

6. Scan breakdown during the turn

What it looks like: during the turn, the pilot fixates on either the turn coordinator (watching the rate) or the HI (watching the heading change), and altitude or airspeed drifts unnoticed.

Why: the new flight phase introduces new instruments to scan; old primaries get dropped.

Fix: the scan continues. AI as anchor; altimeter for pitch (critical due to load factor); turn coordinator for bank rate; ASI for power. The HI is consulted at the rollout window, not continuously throughout the turn.

How errors compound. Over-banking (#1) increases load factor, which makes altitude harder to hold (#3), which forces a power adjustment that affects airspeed. Under-banking (#2) makes the turn take longer than expected, which can cause the pilot to lose track of the target heading and either over- or under-rollout (#4 or #5). The discipline that prevents the chain: calculate the bank before the maneuver, verify with the turn coordinator, and lead the rollout by half the bank angle. Three numbers, three checks, clean turn.