Instrument rating · ACS IR.IV.A
Instrument Flight
Instrument flight is flying the airplane by reference to the instruments alone. The skill is the scan: seeing what the airplane is doing and correcting before small errors grow.
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.
Can’t miss
- •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)
What you should know
The scan and the corrections K1 · K2
- 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 K3
- 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 R1 · R2 · R3
- 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))
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.
Scenarios
Decide what you would do first, then see the worked answer.
You keep busting altitude by 150 feet while copying a clearance.
What’s the fix? See the worked answer
Trim properly before writing, and glance at the attitude indicator between words.
Instrument Flying Handbook (FAA-H-8083-15B), Airplane Attitude Instrument Flying
The heading is slowly drifting and the airplane feels level.
What do you check? See the worked answer
The attitude indicator for a small unwanted bank; level the wings and re-trim. If the wings are level and the ball is centered, suspect heading-indicator precession and realign it with the compass.
Instrument Flying Handbook (FAA-H-8083-15B), Airplane Attitude Instrument Flying
You’re flying a different airplane type with a new glass display tomorrow, in IMC.
Is that a good plan? See the worked answer
Not without training in that display first. Fly it in VMC with an instructor until the scan is natural.
Advanced Avionics Handbook (FAA-H-8083-6)
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.
Now train it
Say it out loud, hear it asked, and take the quick check in this lesson’s practice pack. It tracks your shaky spots.
Got it?
When it feels solid, practice instrument flight out loud with our examiner.
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Go to the source (free)
Teaching this? The instructor lesson plan →
Sources
- Instrument Flying Handbook (FAA-H-8083-15B): Human factors; attitude instrument flying; basic maneuvers; emergency operations
- Advanced Avionics Handbook (FAA-H-8083-6): Automation
- Instrument Rating ACS (FAA-S-ACS-8C): Areas IV and VII
Study aid, not FAA guidance. Regulations change; check the current text at eCFR and the ACS. Checked against current sources 2026-11-13.