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Instrument rating · ACS IR.IV.A · lesson pack

Instrument Flight

Why this one matters

Spatial disorientation is a leading cause of fatal accidents in instrument conditions. The body’s balance sense was built for walking, not for banked turns in cloud, and it gives convincing but false signals. A steady scan and a habit of believing the instruments over your feelings is what keeps the airplane right side up.

1 · Know these cold

  • •Attitude plus power equals performance: set the attitude and power, check the performance instruments, then make small corrections.(Instrument Flying Handbook (FAA-H-8083-15B), Airplane Attitude Instrument Flying)
  • •The attitude indicator is the center of the scan. Look away to one instrument and back to it, again and again.(Instrument Flying Handbook (FAA-H-8083-15B), Airplane Attitude Instrument Flying)
  • •Scan errors: fixation (staring at one instrument), omission (leaving one out), and emphasis (trusting one too much).(Instrument Flying Handbook (FAA-H-8083-15B), Airplane Attitude Instrument Flying)
  • •A standard-rate turn is 3° per second. Bank for standard rate is about 15% of true airspeed.(Instrument Flying Handbook (FAA-H-8083-15B), Airplane Basic Flight Maneuvers)
  • •Your inner ear lies in cloud. The leans: a slow roll goes unsensed, and the abrupt correction feels like a bank the other way; hold wings level on the instruments, don't roll back. A graveyard spiral: power to idle, roll wings level on the attitude indicator, ease the nose to level, then add power.(Instrument Flying Handbook (FAA-H-8083-15B), Human Factors)
  • •Establish, trim, cross-check, adjust: set the attitude and power, trim off the pressure, cross-check the performance instruments, and make small corrections. Trim holds an attitude and airspeed, not an altitude.(Instrument Flying Handbook (FAA-H-8083-15B), Airplane Attitude Instrument Flying)
  • •Checkride standard: altitude ±100 feet, heading ±10°, airspeed ±10 knots, bank ±5° in turns.(Instrument Rating ACS (FAA-S-ACS-8C), IR.IV.A.S1)

2 · The lesson

The scan and the corrections
  • Control and performance method: control instruments (the attitude indicator and the power instruments, such as the tachometer and manifold pressure) set what the airplane does; performance instruments (altimeter, airspeed, heading, VSI, turn coordinator) show the result; navigation instruments (CDI, GPS, DME) show where you are.(Instrument Flying Handbook (FAA-H-8083-15B), Airplane Attitude Instrument Flying)
  • Primary and supporting method: for each maneuver, one instrument is primary for pitch, bank and power (for example altimeter, heading indicator and airspeed in straight and level cruise) and the others support it. Both methods lead to the same scan.(Instrument Flying Handbook (FAA-H-8083-15B), Airplane Attitude Instrument Flying)
  • Climbs and descents: at a constant airspeed, pitch controls airspeed and power sets the rate; at a constant rate, pitch controls the rate on the VSI and power holds the airspeed. Each change ends with trim and a cross-check.(Instrument Flying Handbook (FAA-H-8083-15B), Airplane Basic Flight Maneuvers)
  • Roll out of a turn about half the bank angle before the heading: about 8° early from a 15° bank.(Instrument Flying Handbook (FAA-H-8083-15B), Airplane Basic Flight Maneuvers)
  • Make changes with the attitude indicator in small amounts: a bar width or half a bar of pitch, a few degrees of bank.(Instrument Flying Handbook (FAA-H-8083-15B), Airplane Attitude Instrument Flying)
  • Straight and level, climbs, descents and turns each have a standard attitude and power for your airplane. Learn them.(Your airplane's POH/AFM)
  • Lead the level-off: about 10% of the vertical speed in feet before the target altitude.(Instrument Flying Handbook (FAA-H-8083-15B), Airplane Basic Flight Maneuvers)
  • Know each instrument’s limits: the VSI lags; the attitude indicator shows small errors after turns and speed changes that correct themselves, and older ones tumble past their limits (often about 100-110° of bank or 60-70° of pitch); the heading indicator precesses, so realign it with the compass in straight, level, unaccelerated flight; the compass errs in turns (UNOS) and speed changes (ANDS).(Instrument Flying Handbook (FAA-H-8083-15B), Airplane Attitude Instrument Flying)
When an instrument is wrong
  • If instruments disagree, find the odd one out by checking what else should agree with it. Then cover the bad one.(Instrument Flying Handbook (FAA-H-8083-15B), Airplane Attitude Instrument Flying)
  • Abnormal indications by source. Vacuum: the attitude and heading indicators drift together while the electric turn coordinator disagrees, with low suction. Pitot blocked: the airspeed drops to zero, or acts like an altimeter if the drain is blocked too. Static blocked: the altimeter freezes, the VSI reads zero. Normal heading-indicator precession is slow and steady and the attitude indicator agrees; a failure doesn't match the others.(Instrument Flying Handbook (FAA-H-8083-15B), Airplane Attitude Instrument Flying)
  • Once you've found the failed instrument, cover it and fly on the others.(Instrument Flying Handbook (FAA-H-8083-15B), Airplane Attitude Instrument Flying)
Your body and your equipment
  • Fatigue, stress, hypoxia, alcohol and medications slow the scan. Use IMSAFE before flying into cloud.(Instrument Flying Handbook (FAA-H-8083-15B), Human Factors)
  • The leans: after a slow roll you feel level while banked. The graveyard spiral: a descending turn feels level, and pulling back tightens it.(Instrument Flying Handbook (FAA-H-8083-15B), Human Factors)
  • Head movement in a prolonged turn can cause the Coriolis illusion: a strong tumbling sensation. Keep your head still and use your eyes; do head-down tasks with the wings level.(Instrument Flying Handbook (FAA-H-8083-15B), Human Factors)
  • Other illusions: somatogyral (a long turn stops feeling like a turn; stopping it feels like a turn the other way); somatogravic (acceleration feels like a climb, so you push over; deceleration feels like a descent); inversion (an abrupt level-off feels like tumbling backward); elevator (an updraft feels like a climb). Visual: false horizons from sloping clouds or ground lights, and autokinesis (a stationary light seems to move).(Instrument Flying Handbook (FAA-H-8083-15B), Human Factors)
  • An unfamiliar airplane or avionics display slows your scan. Get training in it before flying it in IMC.(Advanced Avionics Handbook (FAA-H-8083-6))

Want it all on one page, with scenarios? Read the full lesson.

On the flight

ACS standards

  • Maintain altitude ±100 feet during level flight, selected headings ±10°, airspeed ±10 knots, and bank angles ±5° during turns.(Instrument Rating ACS (FAA-S-ACS-8C), IR.IV.A.S1)
  • Use proper instrument cross-check and interpretation, and apply the appropriate pitch, bank, power and trim corrections.(Instrument Rating ACS (FAA-S-ACS-8C), IR.IV.A.S2)

What your instructor is watching for

Your instructor watches for a steady scan that keeps returning to the attitude indicator, small corrections, trim after every change, and no fixation.

3 · Say it out loud

Answer each one out loud, then check yourself and mark how it went.

  1. Remember Recall it

    “What bank gives a standard-rate turn at 100 knots true?”

  2. Understand Explain why

    “Why is the attitude indicator the center of the scan?”

  3. Apply Use it on a flight

    “In cloud you feel sure you’re in a left turn, but the instruments show wings level. What do you do?”

4 · Common mistakes

  • Fixating on one instrument.

    Everything else drifts.

    Instead: Keep the scan moving and return to the attitude indicator.

  • Big corrections.

    You chase the needles.

    Instead: Small attitude changes, then wait.

  • Not trimming.

    Every distraction becomes an altitude change.

    Instead: Trim after every change.

5 · Quick check

Answer, then reveal. Flag anything you want to see again.

  1. 1. What is a standard-rate turn?

  2. 2. Name the three scan errors.

  3. 3. Level-off lead for a 500 fpm climb?

  4. 4. Which illusion makes a descending turn feel level?

  5. 5. Checkride bank tolerance in turns?

  6. Scenario6. Tired after a long day, you’re offered a short IFR flight in cloud. What do you consider?

Trained it? Now prove it: practice instrument flight out loud with our examiner.

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Connect it

One situation that runs across this lesson and its neighbors in the same ACS area. Decide first, then check.

Connect it · Flight by Reference to Instruments

In turbulent IMC the attitude indicator shows a steep nose-high bank, but the altimeter and airspeed are steady and the turn coordinator is centered.

What do you do? Decide, then see the worked answer

Cross-check by axis before you react. Pitch: altimeter, airspeed and VSI are steady, so the nose isn't high. Bank: the turn coordinator's miniature airplane shows no turn and the heading isn't changing, so the wings are level. A centered ball alone only says you're coordinated, not that you're level. Together they say the attitude indicator is failing. Check what shares its power source: if it's a vacuum gyro, check the suction and treat the heading indicator as suspect too. Use the heading indicator only if it's independently powered, verified, and agrees with the compass. Cover the failed gyros and fly partial panel: the turn coordinator for bank; the altimeter, airspeed and VSI for pitch; the compass for direction. Report the malfunction to ATC, as 91.187 requires, and ask for help that cuts your workload, such as no-gyro vectors or a simpler routing or approach. If the other instruments confirm a real unusual attitude, recover: nose high, add power, lower the nose, level the wings; nose low, reduce power, level the wings, raise the nose.

IFH (FAA-H-8083-15B), Attitude Instrument Flying, Unusual Attitudes; 14 CFR 91.187

Brings together: Instrument Flight · Recovery from Unusual Flight Attitudes

Teaching this? The instructor lesson plan →

Study aid, not FAA guidance. Sources: Instrument Flying Handbook (FAA-H-8083-15B); Advanced Avionics Handbook (FAA-H-8083-6); Instrument Rating ACS (FAA-S-ACS-8C). Checked against current sources 2026-11-13.