Instrument Flight
IFH Ch 5–7 • Attitude Flying, Scan, Maneuvers, Partial Panel, Unusual Attitudes
Trust Your Instruments
In IMC, spatial disorientation is the #1 threat. Your body WILL lie to you. Maintain a disciplined scan, trust the instruments, and never chase a single gauge. The graveyard spiral — a nose-low, descending turn that goes unrecognized — is the leading cause of fatal IMC accidents. (AIM 8-1-5, IFH Ch. 3)
Key Takeaways
- GRABCARD lists the instruments required for IFR — it adds to (does not replace) the VFR day/night equipment.
- Three inspection cycles: pitot-static and transponder every 24 calendar months; VOR accuracy check every 30 days.
- On the cockpit check, the altimeter must read within 75 ft of field elevation and the suction gauge must sit in the green arc.
- Brief the missed approach before you need it — never read it for the first time at DA/MDA.
Instrument Cockpit Check
- Altimeter(s): Set current altimeter setting — must read within 75 ft of field elevation (14 CFR §91.411)
- Attitude indicator(s): Erect and stable after 5 minutes; ≤5° bank indication during taxi turns
- Heading indicator / HSI: Set to match magnetic compass heading — confirms gyro spin-up and precession within limits
- Turn coordinator: Shows correct direction of turn during taxi; ball moves opposite to turn direction
- VSI: Indicates zero (or note known calibration error for reference in flight)
- Airspeed indicator(s): Indicating zero (slight movement acceptable in strong wind; cross-check pitot heat functional)
- Magnetic compass: Full of fluid, card swings freely, showing known taxiway/runway heading
- Suction gauge: Check within green arc (typically 4.5–5.5 in Hg) — drives AI and HI in most piston GA aircraft
IFH Ch. 5 / ACS II.C
IFR Required Equipment — GRABCARD
The instruments and systems required to fly IFR
| Letter | Equipment |
|---|---|
| G | Generator or alternator of adequate capacity |
| R | Radios — two-way comm + nav suitable for the route/ATC |
| A | Altimeter (sensitive, adjustable for barometric pressure) |
| B | Ball — slip-skid indicator (inclinometer) |
| C | Clock — hours, minutes, and seconds |
| A | Attitude indicator (artificial horizon) |
| R | Rate-of-turn indicator (turn coordinator) |
| D | Directional gyro (heading indicator / HSI) |
GRABCARD adds to the VFR day/night equipment of §91.205(b)/(c) — it does not replace it.
Also: DME or suitable RNAV is required at FL240+ when using VOR for navigation — rarely a factor for piston GA.
14 CFR §91.205(d)
Required IFR Inspections
Currency cycles for legal IFR flight
| Inspection | Interval | Regulation |
|---|---|---|
| Pitot-static / altimeter system | 24 calendar months | §91.411 |
| Transponder | 24 calendar months | §91.413 |
| VOR accuracy check | 30 days (for IFR) | §91.171 |
| GPS database | Current cycle (for IFR nav) | AIM 1-1-17 |
| ELT battery | Per cumulative-use / expiry | §91.207 |
| Annual inspection | 12 calendar months | §91.409 |
14 CFR §91.171/411/413
Cockpit Setup for IFR
- ATIS/ASOS: Obtain current weather, altimeter setting, active runway, NOTAMs
- Program route: Enter departure, en route waypoints, destination, and alternate in GPS/FMS
- Set nav sources: Tune and identify VOR/ILS frequencies; verify course on CDI/HSI
- Radio stack: Set ground, tower, departure, CTAF, ATIS, and FSS frequencies in standby
- Brief departure: Review ODP or SID, initial heading, altitude restrictions, and departure frequency
- CRAFT clearance: Copy Clearance limit, Route, Altitude, Frequency, Transponder code
- Brief missed approach at destination: Be ready before you need it — do not read it for the first time at DA/MDA
- Backup plan: Know alternate airport weather and approach; have plates readily accessible
ACS II.A–C / IFH Ch. 10
Instrument Takeoff Procedures
- Align aircraft on runway centerline; set heading indicator/HSI to match runway heading
- Note compass heading for reference during initial climb (in case of heading indicator failure)
- Apply takeoff power smoothly; use rudder to maintain centerline, then transition to instruments
- At rotation speed, establish a pitch attitude of approximately 7–10° nose-up on AI (aircraft-dependent)
- Cross-check: Positive rate on VSI, airspeed increasing, altitude increasing — then gear up if retractable
- Maintain runway heading (or assigned heading) until otherwise instructed by ATC
- Transition to instrument scan immediately — do not look back outside once in IMC
- Common error: Fixating on one instrument during initial climb; maintain scan discipline
IFH Ch. 7
Key Takeaways
- The attitude indicator is ALWAYS the basic attitude reference — it is never demoted; other instruments refine it.
- The "primary" instrument changes with phase: altimeter for level, airspeed for constant-airspeed climbs/descents, VSI for constant-rate.
- Three fundamental skills: cross-check (scan), interpretation, and aircraft control — integrated into smooth inputs.
- Trim after every attitude or power change — it is the single most important aid to smooth instrument flying.
Three Fundamental Skills
- Instrument Cross-Check (scanning): Continuous, logical observation of instruments for attitude and performance information
- Instrument Interpretation: Understanding what each instrument indication means relative to the desired flight condition
- Aircraft Control: Making smooth, coordinated, timely inputs based on cross-check and interpretation
- These three skills are learned separately but must be integrated into unified, smooth control responses
- Proficiency = ability to cross-check and interpret simultaneously while maintaining precise control
IFH Ch. 6
Control & Performance Method
- Control instruments display immediate attitude and power: Attitude Indicator (AI), tachometer, manifold pressure
- Performance instruments show actual results: Altimeter, airspeed indicator, VSI, heading indicator
- Navigation instruments show position: CDI, HSI, GPS course, bearing pointers, glideslope
- Step 1: Establish approximate attitude + power on control instruments (known values for the maneuver)
- Step 2: Trim to neutralize control pressures — essential for smooth, hands-off stability
- Step 3: Cross-check performance instruments to verify desired result is being achieved
- Step 4: Adjust attitude and/or power as needed based on performance deviations
IFH Ch. 6
Primary & Supporting Instruments by Phase
Which instrument leads for pitch, bank, and power
The AI is always the hub
The attitude indicator is never "demoted." The table below shows which performance instrument is primary for each control parameter in each phase — but every correction starts from the AI.
| Phase | Pitch | Bank | Power |
|---|---|---|---|
| Straight & level | Altimeter | Heading Indicator | Airspeed Indicator |
| Constant-airspeed climb/descent | Airspeed Indicator | Heading Indicator | Manifold/RPM (set for rate) |
| Constant-rate climb/descent | VSI | Heading Indicator | Airspeed Indicator |
| Standard-rate turn | Altimeter | Turn Coordinator | Airspeed Indicator |
IFH Ch. 6
Bank Instruments & Turns
- Attitude Indicator: Immediate, direct bank indication — basic reference for establishing bank angle
- Heading Indicator: Primary bank instrument in straight-and-level flight (constant heading = zero bank)
- Turn Coordinator: Primary bank instrument in standard-rate turns; shows rate of turn and coordination
- Magnetic Compass: Backup bank reference; affected by turning errors, acceleration errors, oscillation
- Standard-rate turn = 3° per second = 360° in 2 minutes
- Bank angle rule of thumb: (TAS ÷ 10) + 7 — at 100 KTAS: (100/10) + 7 = 17° bank
- Never exceed 30° bank on instruments unless required for an unusual attitude recovery
IFH Ch. 6–7
Pitch Targets & Level-Off Technique
- Level flight: Altimeter (primary), AI & VSI (supporting) — hold altitude precisely
- Level-off: Altimeter transitions to primary as target altitude is approached
- Guideline: Start level-off at 10% of vertical speed (e.g., 500 fpm climb → start 50 ft before target)
- In turbulence: Use the average of VSI fluctuations; rely more heavily on altimeter
- VSI correction rule of thumb: Pitch to produce a VSI rate twice the altitude deviation (100 ft off = 200 fpm correction)
IFH Ch. 6–7
Power Control & Trim
- Power indicators: Tachometer (fixed-pitch), manifold pressure + RPM (constant-speed prop)
- Smooth throttle movements; avoid fixating on power instruments while adjusting
- Know approximate power settings for your aircraft: cruise, climb, approach, slow flight
- Trim: The single most important aid to smooth instrument flying
- Trim after every attitude or power change — goal is hands-off straight-and-level at desired speed
- Improperly trimmed aircraft: Requires constant pressure, distracts from cross-check, leads to fatigue
- Trim for coordinated flight: Center the ball with rudder trim first, then aileron trim for wings-level
- Speed stability: A properly trimmed aircraft tends to return to its trimmed airspeed after a perturbation
IFH Ch. 6
Key Takeaways
- The radial (hub-and-spoke) scan radiates from the AI to each instrument and always returns to the AI — the recommended method.
- Three scan errors the DPE watches for: fixation (staring), omission (skipping an instrument), and emphasis (over-relying on one).
- Tighten the scan to the 3–4 most relevant instruments in high-workload phases (approach, turbulence).
- Instrument proficiency is perishable — it degrades without recency even for experienced pilots.
Cross-Check Patterns Compared
Selected Radial, Inverted-V, Rectangular
| Pattern | Scan Path | Best For |
|---|---|---|
| Selected Radial (hub-and-spoke) | AI ↔ each instrument, always returning through the AI | All phases; best situational awareness (recommended) |
| Inverted-V | AI → Turn Coordinator → AI → VSI → AI | Turns and climbs/descents |
| Rectangular | ASI → AI → ALT (top), then VSI → HI → TC (bottom) | Equal weighting — slow to return to the critical instrument |
IFH Ch. 6
Common Scan Errors
- Fixation: Staring at one instrument (e.g., watching altimeter needle while heading drifts unchecked)
- Omission: Failing to include a relevant instrument in the scan (e.g., forgetting the HI during straight flight)
- Emphasis: Over-relying on one instrument for information better obtained from another
- All three degrade situational awareness and can lead to spatial disorientation or loss of control
- Fixation often occurs when trying to correct a deviation — you stare at the instrument you want to fix
- Cure: Consciously force eyes back to the AI and resume the scan pattern; corrections should be small
IFH Ch. 6
Scan Rate & Adaptation
- No single "correct" scan speed — adapt to the phase of flight and workload
- During transitions (climbs, descents, turns): Increase scan speed to catch trend changes early
- In stable cruise: Relaxed but continuous scan; brief glances suffice for each instrument
- High workload (approach, turbulence): Tighten scan to the 3–4 most relevant instruments
- Instrument interpretation should become nearly instantaneous with practice
- Practice: Time under the hood is the only way to build reliable scan habits
- Even experienced IFR pilots degrade without recency — instrument proficiency is perishable
IFH Ch. 6
Glass Cockpit Scan Considerations
- PFD consolidates attitude, airspeed, altitude, heading, and VSI into one display
- Risk: Easier to fixate on the PFD because "everything is there" — still need to scan MFD, engine, and nav displays
- Scan pattern shifts from "six-pack" hub-and-spoke to PFD-center with glances to MFD and standby instruments
- Ensure standby instruments (usually analog) are included in periodic scan — they are your backup
- Color and trend information on PFDs can improve interpretation speed but can also cause complacency
- Failure modes differ from steam gauges: a single screen failure can remove multiple indications simultaneously
IFH Ch. 6 / AAH Ch. 2
Key Takeaways
- Standard rate = 3°/sec = a full 360° in 2 minutes — the standard for IFR maneuvering.
- Bank angle for a standard-rate turn ≈ (TAS ÷ 10) + 7; lead the roll-out by roughly half the bank angle.
- Glideslope descent rate ≈ groundspeed ÷ 2 × 10 fpm (e.g., 90 kt GS ≈ 450 fpm).
- A 45° steep turn pulls 1.41 G and raises stall speed ~19% — hold airspeed and add power.
Standard-Rate Turn Reference
Bank angle and roll-out lead by true airspeed
- Standard rate = 3°/sec = 360° in 2 minutes — the standard for IFR maneuvering
- Bank angle rule: (TAS ÷ 10) + 7 (at 100 KTAS ≈ 17°; at 120 KTAS ≈ 19°; at 90 KTAS ≈ 16°)
- Turn coordinator: Miniature aircraft aligned with the standard-rate index mark
- Roll-in: Coordinate aileron and rudder; slight back pressure to maintain altitude in the turn
- Roll-out: Lead the target heading by approximately half the bank angle (17° bank → lead ~8–10°)
- Maintain altitude: Altimeter is primary for pitch during a constant-altitude turn
- Common errors: Forgetting back pressure (altitude loss); inconsistent roll-out lead; skid/slip
| TAS (kt) | Std-Rate Bank | Roll-Out Lead |
|---|---|---|
| 90 | ≈16° | ≈8° |
| 100 | ≈17° | ≈8–10° |
| 120 | ≈19° | ≈10° |
| Steep turn | 45° (1.41 G) | ≈22–25° |
IFH Ch. 7
Straight-and-Level Flight
- Objective: Maintain constant altitude, heading, and airspeed simultaneously
- Primary instruments: Altimeter (pitch), Heading Indicator (bank), ASI (power)
- Pitch corrections: Make small changes (half bar width on AI); cross-check altimeter and VSI for trend
- Bank corrections: Wings-level on AI, confirmed by constant heading on HI
- Power corrections: Set approximate power for desired airspeed; fine-tune with ASI indication
- Trim is essential — a properly trimmed aircraft allows you to focus on scan instead of fighting controls
- Common error: Over-controlling pitch — chasing the altimeter leads to a PIO (pilot-induced oscillation)
IFH Ch. 7
Constant-Airspeed Climbs & Descents
- Climb entry: Simultaneously increase pitch (AI) and add power; ASI becomes primary for pitch
- Target pitch attitude: Approximately 2–2.5 bar widths above horizon (aircraft-specific)
- Level-off: Lead the target altitude by 10% of climb rate (500 fpm = lead 50 ft)
- Descent entry: Reduce power first, then lower pitch; ASI primary for pitch
- Level-off from descent: Add power and raise pitch simultaneously at lead point
- Cross-check: AI for attitude reference, ASI for airspeed, altimeter for progress, VSI for trend
- Trim after each power/pitch change — do not try to hold control pressure through the entire maneuver
IFH Ch. 7
Constant-Rate Climbs & Descents
- Used when ATC assigns a specific vertical rate (e.g., "climb and maintain 5,000, 500 feet per minute")
- VSI becomes primary for pitch — set pitch on AI to produce the desired rate, then fine-tune with VSI
- Power set to maintain desired airspeed while climbing/descending at the specified rate
- Same level-off lead applies: 10% of vertical speed before target altitude
- Constant-rate descents common on ILS glideslope: ~500 fpm at 90 KTAS on 3° glideslope
- Rule of thumb for glideslope descent rate: Groundspeed ÷ 2 × 10 = fpm (e.g., 90 kt GS = ~450 fpm)
IFH Ch. 7
Steep Turns (45° Bank)
- ACS requires demonstrating 45° bank turns on instruments; this is an advanced maneuver
- Load factor at 45° = 1.41G — requires significant back pressure to maintain altitude
- Stall speed increases by ~19% at 45° bank — maintain adequate airspeed
- Enter smoothly; increase scan rate once established — altitude changes happen fast
- Power increase may be needed to maintain airspeed due to increased drag
- Roll-out lead: Approximately half the bank angle (22–25° before target heading)
- ACS tolerances: ±100 ft altitude, ±10° heading, ±10 knots airspeed
IFH Ch. 7 / ACS III
Compass Turns & Timed Turns
- Timed turns: Use clock + standard rate (3°/sec) when heading indicator fails
- Example: To turn 90°, hold standard rate for 30 seconds (90 ÷ 3 = 30 sec)
- Compass turns: Magnetic compass has northerly/southerly turning errors and acceleration errors
- UNOS: Undershoot North, Overshoot South — for turns through N/S headings
- Lead/lag correction: ≈15° + half your latitude (at 40°N: lead/lag ≈35°)
- ANDS: Accelerate = North, Decelerate = South (errors on E/W headings)
- Compass is only reliable in unaccelerated, wings-level flight — stabilize before reading
IFH Ch. 7 / PHAK Ch. 8
Key Takeaways
- Vacuum failure kills the AI and HI (gyro-driven); fall back to the electric Turn Coordinator for bank and the magnetic compass for heading.
- A blocked static port affects ALL THREE pitot-static instruments; a blocked pitot affects only the ASI.
- Use timed turns at 3°/sec when the heading indicator is gone — count seconds for the degrees needed.
- Vacuum or electrical failure in IMC is an emergency — declare, keep it simple (standard rate, no steep turns), and get to VMC or an approach.
Instrument Failure Matrix
What you lose, what you keep, and what to do
| Failure | Lost | Still OK | Response |
|---|---|---|---|
| Vacuum failure | AI, HI | Turn Coordinator (electric), ASI, ALT, VSI, compass | TC for bank, compass for heading; declare; get VMC or an approach |
| Blocked static port | ASI, ALT, VSI (all affected) | AI, HI, TC | Alternate static source; if none, break the VSI glass |
| Electrical failure | TC, GPS, radios, transponder, nav displays | AI, HI (vacuum), ASI, ALT, VSI, compass | Declare; ATC primary radar; conserve battery |
| Vacuum + electrical | AI, HI, TC, GPS, radios | Pitot-static instruments + magnetic compass only | Partial panel: timed turns + compass; nearest suitable airport |
IFH Ch. 5–6 / PHAK Ch. 8
Vacuum System Failure
- In most piston GA aircraft, the AI and HI are vacuum-driven (suction gauge shows power status)
- Turn coordinator is electrically driven — remains functional during vacuum failure
- Pitot-static instruments (altimeter, ASI, VSI) are unaffected by vacuum failure
- The AI may tumble, show erroneous indications, or slowly precess after vacuum loss
- Cover or ignore the failed AI to avoid distraction — post a sticky note over it if possible
- Vacuum failure in IMC is an emergency — declare and get vectors to nearest VFR or an approach
- In glass cockpits: PFD failure removes AI + HI + ASI + ALT simultaneously; revert to standby instruments
IFH Ch. 6 / PHAK Ch. 8
Pitot-Static System Failures
- Blocked pitot tube (no drain): ASI reads zero — altimeter and VSI unaffected
- Blocked pitot tube + drain: ASI acts like an altimeter (increases with altitude, decreases on descent)
- Blocked static port: ASI, altimeter, and VSI all affected — freeze at time of blockage
- Alternate static source (if available): Slightly higher altimeter reading, slightly higher ASI due to lower cabin pressure
- If no alternate static: Break the VSI glass to introduce cabin air to the static system
- Icing is the most common cause of pitot-static blockage — ensure pitot heat is ON before entering visible moisture
PHAK Ch. 8 / IFH Ch. 5
Magnetic Compass Errors (UNOS / ANDS)
Turning and acceleration errors, and how to correct
Reliable only straight & level
The compass is trustworthy only in unaccelerated, wings-level flight. In turbulence, average the swings before reading.
| Error | When | Indication | Correction |
|---|---|---|---|
| Northerly turning (UNOS) | Turning through N/S | Compass leads on N, lags on S | Undershoot North (roll out early), Overshoot South (roll out late); lead/lag ≈ 15° + ½ latitude |
| Acceleration (ANDS) | On E/W headings | Accelerate → shows turn toward North; Decelerate → toward South | Read only in stable, unaccelerated flight |
| Oscillation | Turbulence | Card swings continuously | Wait for it to settle; average the swings |
PHAK Ch. 8 / IFH Ch. 6
Partial Panel Technique
- Bank reference: Turn coordinator — standard rate (miniature aircraft aligned with index)
- Heading reference: Magnetic compass (with turning error corrections)
- Pitch reference: Altimeter + ASI + VSI — interpret trends, not instantaneous readings
- Timed turns for heading changes: 3°/sec standard rate — count seconds for degrees of turn needed
- Keep maneuvers simple: Avoid steep turns; use standard rate only
- Trim is even more critical on partial panel — any control pressure becomes a distraction
- Practice partial panel regularly — vacuum failures are rare but survivable only if the skill is current
IFH Ch. 6
Electrical Failure Considerations
- Turn coordinator runs on electricity — if electrical system fails, TC fails too
- With both vacuum AND electrical failure: Only pitot-static instruments + magnetic compass remain
- GPS, radios, transponder, and all nav displays are lost with electrical failure
- Some aircraft have battery-backed standby AI/HI — know your aircraft systems
- Battery backup duration varies: Typically 30–60 minutes for standby instruments
- Declare an emergency immediately; ATC can provide radar vectors using primary radar returns
IFH Ch. 6 / ACS II.C
Key Takeaways
- Nose-high recovery: add FULL power, lower the nose to level, then level the wings (power first to prevent a stall).
- Nose-low recovery: reduce power, LEVEL THE WINGS, then raise the nose — pulling in a bank tightens the spiral and piles on G.
- The graveyard spiral is the #1 IMC killer — an unrecognized nose-low descending turn.
- In IMC the vestibular system lies; the only reliable recovery is to trust and act on the instruments.
Unusual Attitude Recovery — Nose-High vs Nose-Low
Opposite power-and-control sequences — do not mix them up
| Nose-High | Nose-Low | |
|---|---|---|
| Recognition | Decreasing airspeed, climbing VSI, nose-up AI | Increasing airspeed, descending VSI, nose-down AI |
| Power | Add FULL power (prevent stall) | Reduce to idle (prevent overspeed) |
| Sequence | Power → lower nose to level → level wings | Reduce power → level wings → then raise nose |
| Critical caution | Do NOT pull back — it deepens the stall | Level wings BEFORE pulling — pulling in a bank tightens the spiral |
| If AI failed | ASI (increasing = nose dropping) + TC for wings | ASI + TC for wings; respect Vne/Vno |
IFH Ch. 7
Common Errors Leading to Unusual Attitudes
- Inattention to instrument indications (poor scan discipline)
- Fixation on one instrument during a correction
- Failure to recognize instrument malfunction (trusting a tumbled AI)
- Attempting to fly by "feel" instead of instruments in IMC
- Spatial disorientation from head movement, illness, fatigue, or hypoxia
- Turbulence combined with a slow or erratic scan
- Overcontrolling pitch or bank — chasing instruments leads to PIO
- Prevention > Recovery: A good scan catches the trend before it becomes an unusual attitude
IFH Ch. 7
Spatial Disorientation Illusions
- The Leans: Most common illusion — slow, unnoticed bank; sudden correction creates false bank sensation
- Somatogravic Illusion: Rapid acceleration (takeoff) creates false pitch-up sensation → pilot pushes nose down
- Inversion Illusion: Abrupt change from climb to level flight creates sensation of tumbling backward
- Graveyard Spiral: Unrecognized bank → nose drops → pilot pulls back (tightens spiral) → increasing descent rate
- Coriolis Illusion: Moving head in one plane while turning creates violent tumbling sensation
- Vestibular system is unreliable in IMC — evolved for ground use, not instrument flight
- ONLY reliable cure: Trust the instruments. There is no other option in IMC.
- If experiencing disorientation: Resist the urge to "correct" based on body feel; focus on AI, verify with other instruments
AIM 8-1-5 / IFH Ch. 3
Upset Prevention & Recovery Training (UPRT)
- UPRT emphasizes prevention through awareness, scan discipline, and CRM
- Startle factor: Practice unusual attitudes to reduce reaction time when it happens for real
- Any pitch > 25° nose-up or > 10° nose-down, or bank > 45° constitutes an upset per industry definition
- Recovery priorities: (1) Recognize, (2) Confirm with instruments, (3) Recover, (4) Stabilize
- Trained pilots recover in 2–3 seconds; untrained pilots may take 10+ seconds — altitude loss can be extreme
- ACS practical test includes unusual attitude recovery under the hood — expect this on your checkride
IFH Ch. 7 / ACS III.B
Go Deeper
Question about attitude instrument flying, the scan, or partial-panel procedures? Ask Kit for a CFI-level explanation.
“Walk me through flying partial panel after a vacuum failure in IMC”
Training aid only — verify all data against your POH and current FAA publications.