Principles & why

A turn to a heading by instruments combines the scan-pattern doctrine (VIII.A) with horizontal motion for the first time in Area VIII. Three principles drive the task: the standard rate turn as the universal building block; load factor management without visual reference (the math from V.A applied to instrument flight); and the anticipation rule that makes the rollout precise.

The standard rate turn

A standard rate turn is a turn that completes 360° in two minutes, or equivalently, 3 degrees per second of heading change.

Why this rate matters:

• Predictable timing. A pilot can mentally plan a heading change because the duration is calculable. Need to turn 90°? That's 30 seconds at standard rate.
• Instrument cross-check timing. The 3°/sec rate is slow enough that the scan can keep up — the pilot can detect altitude or airspeed drift between rate-of-turn checks.
• Coordinated comfort. Standard rate at typical PPL airspeeds (80–120 kt) requires a bank of 15–19° — gentle enough that load factor doesn't dominate cockpit workload.

The bank angle for standard rate at any airspeed:

Bank (degrees) ≈ TAS (kt) ÷ 10 + 7

At 80 kt: 15°. At 100 kt: 17°. At 120 kt: 19°. The formula is approximate but close enough for in-the-cockpit calculation.

Load factor under the hood

The math from steep turns (V.A.PRI) applies directly:

V_S × √n = stall speed at load factor n n = 1 / cos(bank angle)

At 17° bank, n = 1.05 — only 5% increase in stall speed. At standard rate banks, load factor is gentle; the airplane isn't close to stall.

But the pitch attitude must change to maintain altitude:

• Wings level at 1g: pitch attitude X.
• 17° bank, holding altitude: pitch attitude X + back pressure to produce 5% more lift.

Without visual reference, the only feedback that you've added the right back pressure is the altimeter — if it stays steady, the back pressure is right. If it sinks, more back pressure; if it rises, less.

The scan must include the altimeter before rolling into the turn (entry baseline) and continuously during the turn (to detect altitude drift early). A pilot whose scan drops the altimeter during the turn doesn't notice the load-factor-induced sag until it's a ±100 ft bust.

Anticipation: half the bank angle for rollout

When you start the rollout from a 17° bank, the airplane continues to turn during the rollout itself. The rollout takes about 5 seconds in a typical trainer at standard rate. During those 5 seconds:

• The airplane's heading is still changing at decreasing rate.
• The integral of the changing rate is the heading change during the rollout.
• This integral is approximately half the bank angle in degrees of heading change.

So: a 17° bank rollout adds ~8° of heading change during the rollout. To arrive on target heading wings-level, begin the rollout when the HI shows target − 8° (in the direction of the turn).

The general rule:

Lead the rollout by half the bank angle.

For different bank angles:

• 10° bank → lead by 5°.
• 17° bank (standard) → lead by 8–9°.
• 30° bank → lead by 15° (rarely needed at standard rate).

This is the same anticipation discipline as the climb / descent level-off (B, C) — the airplane has rotational momentum; anticipate it.

Slide the bank angle to see how the rollout lead grows from 5° at 10° bank to 15° at 30°. Toggle to the climb or descent mode to confirm: it's the same anticipation rule with a different proportion factor.

Why this maneuver matters

Turns to headings by instruments are the third basic instrument maneuver (after S&L and climbs/descents) and the last building block before unusual attitude recovery (VIII.E). Combined, A + B + C + D make up the standard hood-time training package: straight flight, vertical changes, horizontal changes.

The maneuver also rehearses the load factor + altitude management discipline that becomes critical in the unusual-attitude recovery task (E) — where a nose-low recovery in a bank requires leveling the wings before pitching out to avoid an accelerated stall. The same load-factor math, applied at much higher consequence.

The scan compresses for the rollout window

In the steady-state turn, the scan is AI-centered with altimeter and turn coordinator as the most-checked primaries. At the rollout window (the last 10° of heading change before the target), the scan compresses:

• HI becomes the most-checked primary (timing the rollout).
• Turn coordinator falls off (the rollout is in progress).
• Altimeter stays critical (load factor releasing requires back-pressure reduction).

After the rollout, the scan returns to the straight-and-level pattern. The compression-and-release is part of the maneuver — VIII.D trains it explicitly.

The Turn phase shifts the bank primary to the Turn Coordinator (verifying the standard rate) and keeps ALT primary for pitch (because altitude is being held against load factor). HI is the rollout-window destination, not continuous primary.

What this task feeds into

VIII.D builds toward:

• VIII.E (unusual attitude recovery) — uses the bank-management and load-factor discipline trained here.
• Future approach training (CFII / IFR) — every instrument approach involves turns to headings, often at standard rate, often with anticipation rules.
• Visual flight discipline reinforced — the same standard rate and lead-the-rollout logic applies in any heading change, visual or instrument. Practiced under the hood, it transfers immediately.