Helicopter Flight Instruments and Navigation Equipment

Objective

The student will demonstrate comprehensive understanding of helicopter flight instruments and navigation equipment required for IFR operations, including normal operation, failure modes, and risk management considerations. Upon completion, the student will accurately identify, operate, and manage all installed instruments and navigation systems to the standards of the Instrument Helicopter ACS Task IH.II.B, with emphasis on single-pilot IFR helicopter operations and automation management.

Measurable Outcomes (ACS IH.II.B):

• Explain the principles, operation, and limitations of pitot-static, gyroscopic/electric, and magnetic compass systems
• Describe operation of VOR, DME, ILS, GPS/WAAS, and RNAV systems in helicopter applications
• Identify failure modes and instrument/navigation system errors
• Demonstrate proper management of installed and portable navigation equipment
• Apply risk management principles for automated systems and navigation databases

Content

A. Pitot-Static Instrument System and Associated Instruments (IH.II.B.K1a)

System Components: The pitot-static system provides critical information for three primary flight instruments: airspeed indicator, altimeter, and vertical speed indicator. In helicopters, accurate pitot-static information is essential for compliance with ATC clearances and approach procedures where specific airspeeds and altitudes are mandatory.

Pitot Tube:

• Measures dynamic (ram) air pressure
• Typically mounted away from rotor wash and fuselage effects
• Must remain unobstructed—preflight inspection critical
• Heated pitot systems prevent ice accumulation in IMC (reference 14 CFR §91.205 for IFR equipment requirements)

Static Port(s):

• Measure ambient atmospheric pressure
• Usually flush-mounted on fuselage sides
• Some helicopters have alternate static source in cockpit (typically reads 50-100 feet lower in flight due to venturi effect)

Airspeed Indicator:

• Displays difference between pitot and static pressure
• Color-coded for VNE (red line), caution range (yellow arc), normal operating range (green arc)
• Helicopter-specific consideration: Forward airspeed in IMC must be carefully managed—many training helicopters lack stability augmentation systems, making high-speed IFR operations more demanding
• Errors: position error (varies by airspeed), density error (corrected with TAS calculations), blocked pitot (acts like altimeter), blocked static (airspeed reads lower in climb, higher in descent)

Altimeter:

• Aneroid barometer calibrated in feet
• Three-pointer design standard (smallest = 10,000 ft, medium = 1,000 ft, largest = 100 ft)
• Kollsman window for barometric correction
• 14 CFR §91.121 requires correct setting (below 18,000 ft: local altimeter; at/above 18,000 ft: 29.92” Hg)
• IFR requirement (14 CFR §91.411): Altimeter system and altitude reporting equipment must be inspected every 24 calendar months
• Errors: temperature (actual altitude lower than indicated on cold days—critical in mountainous terrain), non-standard pressure (altimeter reads high when flying from high to low pressure)

Vertical Speed Indicator (VSI):

• Displays rate of altitude change in feet per minute
• Operates on differential pressure rate-of-change principle
• 6-9 second lag in standard VSI (instantaneous VSI/IVSI available in some helicopters)
• Helicopter applications: used to establish and maintain precise climbs/descents during approaches; critical for compliance with “descend and maintain” clearances

Blockage Scenarios:

• Blocked pitot only: airspeed reads zero, altimeter and VSI unaffected
• Blocked static only: airspeed reads incorrectly, altimeter freezes, VSI reads zero
• Both blocked: all three instruments unreliable
• Alternate static source activation required—expect momentary fluctuations

B. Gyroscopic/Electric Instrument System and Associated Instruments (IH.II.B.K1b)

Gyroscopic Principles: Rigidity in space and precession govern gyroscopic instruments. Most training helicopters use electrically-driven gyros (attitude indicator, heading indicator) or vacuum/pressure-driven systems in older models.

Attitude Indicator:

• Displays pitch and roll relative to horizon
• Critical for helicopter IFR: Primary pitch and bank reference in IMC—helicopters have no natural aerodynamic stability, making continuous cross-check essential
• Modern attitude indicators: electric or solid-state AHRS (Attitude and Heading Reference System)
• Limitations: pitch limits typically ±60-70°, bank limits ±100-110°, tumbles if exceeded (not applicable to solid-state systems)
• Errors: slight pitch error during acceleration/deceleration, may precess over time
• Backup instruments required (14 CFR §91.205(d))—usually standby attitude indicator

Heading Indicator (Horizontal Situation Indicator):

• Displays helicopter heading without magnetic compass errors
• Must be periodically aligned with magnetic compass (approximately every 15 minutes due to precession)
• Slaved vs. unslaved: slaved systems (HSI with flux valve) automatically align; unslaved require manual adjustment
• Helicopter consideration: Vibration can accelerate precession—more frequent checks needed than in airplanes

Turn Coordinator:

• Displays rate of turn and roll rate
• Standard rate turn = 3° per second (360° in 2 minutes)
• Inclinometer (ball) shows slip/skid—critical for coordinated flight
• Helicopter-specific: Turn coordination in IMC requires smooth pedal inputs to prevent skidding; rotor system differences (underslung vs. semi-rigid vs. rigid) affect coordination requirements
• Electric-powered—remains operational if vacuum system fails
• Required backup instrument for IFR (typically serves as backup if attitude indicator fails)

Power Sources:

• Electric systems: 14V or 28V DC electrical bus
• Vacuum/pressure systems: engine-driven vacuum pump (typically 4.5-5.5” Hg suction)
• Failure recognition: electric failure shown by flags/OFF indicators; vacuum failure shown by suction gauge

C. Electrical Systems, Electronic Flight Displays, Transponder, and ADS-B (IH.II.B.K1c)

Helicopter Electrical Systems:

• Typical configuration: 14V or 28V DC system with alternator/generator and battery
• Battery: emergency backup (typically 30-45 minutes for essential avionics)
• Circuit breakers/fuses protect individual circuits
• Master switch controls entire electrical system
• Ammeter/loadmeter: monitors charging system performance
• Critical for IFR: Loss of alternator requires immediate action—most training helicopters cannot sustain full avionics load on battery alone for extended periods

Primary Flight Display (PFD):

• Integrates attitude, airspeed, altitude, heading, VSI, slip/skid in single display
• Tape-style presentations replace round dials
• Trend vectors show where parameters will be in 6-10 seconds
• Reversionary modes: PFD can display MFD information if MFD fails, and vice versa
• Helicopter applications: Synthetic vision systems (SVS) particularly valuable given high workload of single-pilot helicopter IFR

Multi-Function Display (MFD):

• Moving map with GPS position, navigation data, terrain awareness
• Engine parameters, traffic information, weather overlays
• Flight plan management interface
• System status and checklist pages

Glass Cockpit Failure Modes:

• Individual display failures: use reversionary mode per POH/AFM
• Complete electrical failure: revert to standby instruments (attitude indicator, altimeter, airspeed, compass)
• Partial panel procedures critical—standby instruments must remain functional per 14 CFR §91.205

Transponder:

• Mode A: 4-digit code only
• Mode C: code plus pressure altitude
• Mode S: Mode C plus unique aircraft identifier, enables ADS-B
• 14 CFR §91.413: transponder requires inspection every 24 calendar months
• Codes: 1200 (VFR), assigned codes for IFR, 7500 (hijack), 7600 (comm failure), 7700 (emergency)
• Operation: squawk assigned code, altitude reporting ON, select appropriate mode per ATC instructions

ADS-B (Automatic Dependent Surveillance-Broadcast):

• ADS-B Out required for operations in Class A, B, C airspace and above Class B/C veils (14 CFR §91.225)
• Broadcasts GPS position, altitude, velocity, and aircraft identification
• ADS-B In (optional): receives traffic (TIS-B) and weather (FIS-B) information
• Helicopter consideration: ADS-B provides situational awareness critical for single-pilot IFR operations—traffic awareness reduces collision risk during approaches

D. Magnetic Compass (IH.II.B.K1d)

Operating Principles: The magnetic compass is the only completely self-contained direction-indicating instrument in most helicopters. It aligns with Earth’s magnetic field and is required equipment for IFR (14 CFR §91.205(d)).

Construction:

• Magnetized steel bars attached to float in compass fluid (kerosene-based)
• Compass card rotates freely in housing
• Lubber line indicates helicopter heading

Compass Errors:

1. Variation: Difference between true north and magnetic north—shown on sectional charts as isogonic lines; corrected by applying variation to convert between true and magnetic headings
2. Deviation: Magnetic fields from helicopter electrical systems and metal components cause compass errors that vary by heading; recorded on compass correction card mounted near compass
3. Magnetic Dip Errors:
   • Acceleration/Deceleration Error (ANDS): Accelerate North, Decelerate South—compass lags on east/west headings during speed changes
   • Turning Errors (UNOS): Undershoot North, Overshoot South—compass leads/lags during turns through north/south headings
   • Errors most pronounced near magnetic poles, negligible near equator

Using the Compass:

• Primary heading reference only in straight-and-level unaccelerated flight on east/west headings
• Used to set/check heading indicator
• Helicopter IFR technique: During heading indicator failure, fly timed turns using turn coordinator and confirm final heading on compass after stabilizing

Compass Limitations:

• Unreliable during turns, climbs, descents, or speed changes
• Oscillates in turbulence (damping fluid reduces but doesn’t eliminate)
• Can be rendered useless by nearby electronic devices or metal objects

E. VOR, DME, ILS, and Marker Beacon Systems (IH.II.B.K2a)

VOR (VHF Omnidirectional Range):

• Line-of-sight navigation system operating 108.00-117.95 MHz
• Provides magnetic bearing TO or FROM station
• VOR receiver displays: CDI (Course Deviation Indicator), TO/FROM flag, OBS (Omnibearing Selector)
• CDI sensitivity: full-scale deflection = 10° for standard VOR
• Helicopter applications: VOR approaches common at non-towered airports lacking GPS approaches; most helicopter VOR receivers integrated into GPS/NAV systems
• 14 CFR §91.171: VOR system must be checked every 30 days for IFR—VOT (±4°), ground checkpoint (±4°), airborne checkpoint (±6°), dual VOR cross-check (±4°), or selected radial over known landmark (±6°)
• Service volumes: Terminal (T) 1,000-12,000 ft AGL 25 NM; Low altitude (L) up to 18,000 ft 40 NM; High altitude (H) up to 45,000 ft 130 NM

DME (Distance Measuring Equipment):

• Paired with VOR or ILS to provide slant-range distance in nautical miles
• Interrogates ground station, measures time for signal return
• Displays distance, groundspeed (computed from distance rate-of-change), and time-to-station
• Helicopter consideration: Low altitudes mean slant-range error minimal—at 6,000 ft AGL directly over station, DME reads 1.0 NM

ILS (Instrument Landing System):

• Precision approach system with localizer (lateral guidance) and glideslope (vertical guidance)
• Localizer: 108.10-111.95 MHz (odd tenths only), provides runway centerline guidance
  • Width: 700 feet at threshold (full-scale deflection = 2.5° each side, varies by runway length)
  • Usable 18 NM on centerline, 10 NM at 35° either side within 10° of centerline
• Glideslope: Typically 3° descent path (may vary by airport)
  • 329.15-335.00 MHz (paired automatically with localizer frequency)
  • Usable to 10 NM, full-scale deflection = 0.7° (narrower than localizer—approximately 1.4° total from full-up to full-down)
• Helicopter ILS considerations:
  • Most helicopter ILS approaches are to higher minimums than Category I (typically 300-400 ft HAT)
  • Slower approach speeds allow better tracking but make helicopter more susceptible to wind drift
  • Glideslope intercept from below preferred—descending through causes reverse sensing momentarily

Marker Beacons:

• Transmit 75 MHz signal vertically at specific distances from runway
• Outer Marker (OM): Blue light, low-pitched tone (400 Hz), 2 dashes/second—typically at glideslope intercept altitude
• Middle Marker (MM): Amber light, medium-pitched tone (1300 Hz), alternating dot-dash—typically at Category I DA (200 ft HAT)
• Inner Marker (IM): White light, high-pitched tone (3000 Hz), 6 dots/second—Category II approaches
• Many ILS approaches now use DME fixes or GPS waypoints in lieu of marker beacons

F. RNAV, GPS, WAAS, FMS, and Autopilot (IH.II.B.K2b)

Area Navigation (RNAV) Concepts: RNAV allows point-to-point navigation without overflying ground-based navaids. GPS is the primary RNAV system for helicopters.

GPS (Global Positioning System):

• Satellite-based navigation providing 3D position, velocity, and time
• Requires 4+ satellites for 3D position fix
• RAIM (Receiver Autonomous Integrity Monitoring): Self-checks GPS accuracy; required for IFR (except with WAAS)
• GPS approach types:
  • LNAV: Lateral navigation only, non-precision (similar to VOR or NDB approach minimums)
  • LNAV/VNAV: Lateral and vertical guidance, non-precision (baro-aided or GPS-computed vertical)
  • LPV: Localizer Performance with Vertical guidance, precision-like (requires WAAS, minimums similar to ILS)
  • LP: Localizer Performance, lateral only (WAAS lateral, no vertical)

WAAS (Wide Area Augmentation System):

• Ground stations correct GPS errors, broadcast corrections via geostationary satellites
• Improves accuracy from ~100 meters to ~1 meter
• Enables LPV approaches with minimums as low as 200-250 ft HAT
• Helicopter WAAS GPS: Transformative technology—provides precision-like approaches at thousands of airports without ILS
• WAAS-capable GPS does not require RAIM prediction—integrity monitoring built into WAAS signal

GPS Database (Addresses IH.II.B.R5):

• 28-day update cycle to match aeronautical chart cycle
• 14 CFR §91.175 and AC 90-108: Current database required for IFR GPS approaches
• Expired database risk: Frequencies, waypoint coordinates, obstacle clearance data may be incorrect—pilots may use expired database for en route but NOT for approaches unless procedure verified against current source
• Flight plan filed as /G (GPS RNAV) requires operational GPS with current database

FMS (Flight Management System):

• Advanced GPS/NAV integration with flight planning, performance calculations, autopilot coupling
• More common in turbine helicopters; rare in piston training helicopters
• Functions: flight plan creation, active/standby flight plan management, procedure (DP/STAR) loading, holds, direct-to navigation

Autopilot (Helicopter-Specific Discussion):

• Critical understanding: Most piston training helicopters (R22, R44, Schweizer 300) have NO autopilot
• Turbine helicopters may have 2-axis (roll and pitch) or 3-axis (roll, pitch, yaw) autopilots with altitude hold, heading hold, and NAV/GPS coupling
• Single-pilot IFR implications: Without autopilot, helicopter IFR requires continuous manual control—significantly higher workload than fixed-wing, especially during approach procedures
• Autopilot failure modes: immediate disconnect if out-of-trim force detected, manual override via quick-disconnect button or control movement, reversion to manual flight required
• Risk management (IH.II.B.R1): If autopilot available, pilot must continuously monitor—automation complacency major risk factor; understand engagement/disengagement procedures; practice manual flight regularly

G. Electronic Flight Bags (IH.II.B.K3, IH.II.B.R4)

EFB Categories:

• Type A (Portable): Consumer device (iPad, Android tablet), not certified, operator-supplied
• Type B (Portable): Mounted device, connected to aircraft power/data, not certified
• Type C (Installed): Certified aircraft system with installation approval

Approved vs. Non-Approved Devices (IH.II.B.R2):

• Non-approved EFB (Type A/B): May be used for charts, flight planning, W&B calculations, checklists as reference only—cannot be sole source for IFR navigation; paper backup required if used for primary chart source
• Approved navigation devices: Panel-mounted GPS certified to TSO-C129, C145, C146 (WAAS)—may be used as primary navigation source for IFR
• AIM 1-1-17 and AC 91-78: Guidance on GPS use for IFR operations
• Portable GPS (e.g., Garmin aera, iPad with GPS): Not approved for IFR navigation—situational awareness only

EFB Applications:

• ForeFlight, Garmin Pilot, FltPlan Go: Moving map, geo-referenced approach plates, weather overlays, flight planning, W&B
• Risk management: Battery life (carry backup battery or charger), overheating (direct sunlight), software crashes, currency of data
• Best practices:
  • Charge before flight
  • Secure mounting to prevent interference with controls
  • Brightness reduction to extend battery, prevent night vision loss
  • Verify chart dates match current cycle
  • Have paper/backup charts for critical phases (approach plates for destination/alternate)

H. Risk Management Integration (IH.II.B.R1-R5)

Monitoring and Management of Automated Systems (IH.II.B.R1):

• Mode awareness: Always know what mode the autopilot or GPS is in (HDG, NAV, ALT HOLD, etc.)
• Immediate intervention: If automation behaves unexpectedly, disconnect and hand-fly
• Sterile cockpit: Minimize automation programming below 10,000 ft or inside FAF
• Helicopter-specific risk: Higher workload in manual flight means automation (if available) extremely valuable but creates complacency risk

Difference Between Approved and Non-Approved Navigation Devices (IH.II.B.R2):

• Only TSO-certified, installed GPS may be used for IFR navigation
• Portable GPS is supplemental only—provides awareness but not legal navigation authority
• VOR/ILS certified under aircraft type certificate—approved for IFR
• Paper or electronic charts: both acceptable if electronic charts current and accessible

Modes of Flight and Navigation Instruments, Including Failure Conditions (IH.II.B.R3):

• GPS modes: En route (±2 NM sensitivity), Terminal (±1 NM), Approach (±0.3 NM for LNAV/VNAV, ±350 ft for LPV)
• GPS failure recognition: Loss of RAIM, insufficient satellites, “LOI” (loss of integrity) annunciation—requires immediate reversion to alternate navigation (VOR, ADF if available, or radar vectors)
• Pitot-static blockage: Recognize unreliable instruments, use backup sources (GPS groundspeed/altitude)
• Gyro failure: Revert to compass, turn coordinator, GPS for heading information
• Electrical failure: Revert to standby instruments; if total electrical failure in IMC, ATC expects radio failure procedures (14 CFR §91.185)

Use of Navigation Databases (IH.II.B.R5):

• Currency critical: Verify database expiration date before IFR flight
• Approach procedure verification: Cross-check approach plate frequencies, course, minimums vs. GPS-loaded procedure
• Notam review: GPS-based approaches may be NA due to satellite outages or system issues—check NOTAMs

I. Regulatory References

• 14 CFR §91.121: Altimeter settings
• 14 CFR §91.171: VOR equipment check for IFR
• 14 CFR §91.175: Takeoff and landing under IFR—GPS database currency
• 14 CFR §91.205(d): Instrument and equipment requirements for IFR
• 14 CFR §91.225: ADS-B Out equipment and use
• 14 CFR §91.411: Altimeter system and altitude reporting equipment tests and inspections
• 14 CFR §91.413: ATC transponder tests and inspections
• AIM Chapter 1-1: Navigation Aids
• FAA-H-8083-15B (Instrument Flying Handbook): Chapters 5 (Flight Instruments), 9 (Navigation Systems)
• FAA-H-8083-25B (Pilot’s Handbook of Aeronautical Knowledge): Chapter 8 (Flight Instruments)
• AC 90-108: Use of Suitable RNAV Systems
• AC 91-78: Use of Class 1 or Class 2 EFB

Schedule

Note: Schedule assumes ground-based training. If conducted in helicopter, adjust for preflight/postflight time.

Equipment

Required References

• FAA-S-ACS-14 Instrument Rating – Helicopter ACS (current edition)
• FAA-H-8083-15B Instrument Flying Handbook
• FAA-H-8083-25B Pilot’s Handbook of Aeronautical Knowledge
• 14 CFR Parts 61, 91 (current edition)
• Aeronautical Information Manual (AIM), current edition
• AC 90-108 Use of Suitable RNAV Systems on Conventional Routes and Procedures
• AC 91-78 Use of Class 1 or Class 2 Electronic Flight Bag (EFB)
• Helicopter POH/AFM (specific to training aircraft—e.g., Robinson R44, R22, Schweizer 300CBi)

Training Materials

• Whiteboard and markers for system diagrams
• Instrument panel photographs or diagrams (pitot-static, gyroscopic, electrical systems)
• Sample avionics: PFD/MFD screenshots or training panels
• VOR sectional chart excerpt with isogonic lines
• ILS approach plate (helicopter-specific)
• GPS approach plate examples (LNAV, LNAV/VNAV, LPV)
• Sample compass correction card
• Magnetic compass demonstration model (if available)

Visual Aids

• Pitot-static system flow diagram
• Gyroscopic instrument cutaway illustrations
• Electrical system schematic for training helicopter
• ILS localizer/glideslope geometry diagram
• GPS constellation and WAAS ground station map
• EFB screenshot examples (ForeFlight, Garmin Pilot)

Equipment for Demonstration

• Training helicopter or approved flight training device with functional instruments and navigation equipment
• EFB (iPad or Android tablet) with current aeronautical database
• Handheld aviation GPS (for approved vs. non-approved discussion)
• Flashlight (for demonstrating instrument lighting and backup procedures)

Instructor Actions

1. Conduct lesson introduction by stating objectives and explaining this lesson establishes foundational knowledge for all subsequent instrument flight training—emphasize that single-pilot helicopter IFR demands intimate familiarity with every instrument and navigation system due to high workload and limited automation in most training helicopters.

2. Present pitot-static system overview using whiteboard diagram showing pitot tube, static port(s), and connections to airspeed indicator, altimeter, and VSI. Explain that unlike airplanes with enclosed cockpits, helicopter pitot-static systems must account for rotor downwash and vibration effects on static port placement.

3. Demonstrate pitot-static instrument readings by walking through example scenarios: level flight at constant airspeed (all instruments steady), climb at constant airspeed (altimeter increasing, VSI positive, airspeed constant), and blockage scenarios (blocked pitot: airspeed reads zero; blocked static: altimeter freezes).

4. Explain altimeter setting procedures per 14 CFR §91.121—local altimeter below 18,000 ft MSL, standard setting (29.92” Hg) at and above FL180. Use analogy: “The altimeter is like a clock that needs resetting as you move through different pressure zones—forget to update it and you’re flying at the wrong altitude without knowing it.”

5. Teach altimeter error sources with emphasis on cold weather operations. Show calculation: on a standard day at 5,000 ft indicated, actual altitude equals indicated; on a day 20°C below standard, actual altitude approximately 4% lower per 1,000 ft (approximately 4,600 ft actual at 5,000 ft indicated). State: “This matters in mountainous terrain—MEAs and approach minimums assume standard temperature.”

6. Describe gyroscopic instrument principles by explaining rigidity in space (“a spinning gyro wants to maintain its orientation in space—think of a spinning top resisting being tipped over”) and precession (“apply force to a spinning gyro, and it reacts 90° in the direction of rotation—this is why attitude indicators have limits”).

7. Demonstrate attitude indicator interpretation using cockpit panel or training device, showing pitch reference (horizon bar and pitch marks), bank reference (bank index at top), and miniature helicopter symbol. Explain that in helicopters, continuous reference to attitude indicator is essential because helicopters have no inherent stability—remove cyclic input in IMC, and the helicopter will roll or pitch uncommanded.

8. Explain heading indicator operation and precession—show that unslaved heading indicators drift due to bearing friction and earth’s rotation (approximately 3° per 15 minutes in training helicopters). Demonstrate setting procedure: align heading indicator to magnetic compass only when in straight-and-level unaccelerated flight on east or west heading.

9. Demonstrate turn coordinator use for establishing standard-rate turns (3° per second, full winglet deflection). Explain ball (inclinometer) function: “Ball toward turn = skidding (too much pedal), ball away from turn = slipping (not enough pedal). In helicopters, proper pedal coordination in IMC prevents loss of directional control and reduces pilot workload—step on the ball to center it.”

10. Present electrical system architecture specific to training helicopter using POH/AFM electrical diagram. Identify alternator/generator, battery, master switch, avionics master, circuit breakers, and essential bus (if equipped). Explain that loss of alternator in IMC requires immediate workload reduction—shed non-essential electrical loads, advise ATC, and plan to land ASAP (most training helicopters have 30-45 minute battery reserve at reduced electrical load).

11. Describe PFD operation and features using screenshots or training device: tape-style airspeed and altitude displays, attitude sphere, HSI, VSI tape, slip/skid indicator, trend vectors. Explain reversionary modes: “If your PFD fails, you can usually display its information on the MFD by pressing the reversionary button—but know where your standby instruments are and use them immediately.”

12. Explain MFD functions including moving map, flight plan display, traffic, weather, and engine parameters. Demonstrate how to interpret MFD moving map: magenta flight plan line, direct-to course, GPS track (extended centerline), bearing pointer, range rings. State: “The MFD is your strategic display—big-picture navigation, traffic, weather. The PFD is tactical—immediate flight control.”

13. Teach transponder operation by identifying Mode A/C/S selector, code entry, IDENT button, and altitude reporting. Explain required inspections (14 CFR §91.413: every 24 calendar months). Review special codes: 1200 VFR, 7500 hijack, 7600 radio failure, 7700 emergency. State: “In helicopters flying IFR at lower altitudes, your transponder provides ATC the only reliable method of tracking you on radar—keep it on and set correctly.”

14. Describe ADS-B Out requirements per 14 CFR §91.225—required in Class A, B, C, above Class B/C veils, and above 10,000 ft MSL (with exceptions). Explain ADS-B In benefits (traffic and weather) but emphasize limitations: traffic display shows only aircraft equipped with ADS-B Out or tracked by ATC radar; not all traffic shown.

15. Explain magnetic compass construction and use by showing compass or using demonstration model. Identify lubber line, compass card, correction card. State: “The magnetic compass is your only self-contained heading reference—if all electrical systems fail, the compass keeps working. But it has errors and is unreliable except in straight-and-level unaccelerated flight.”

16. Teach compass errors using ANDS/UNOS mnemonics—Accelerate North Decelerate South for acceleration/deceleration error on east/west headings; Undershoot North Overshoot South for turning errors through north/south headings. Demonstrate: “Flying east at constant speed, you accelerate—compass temporarily shows turn toward north even though you’re still heading east. Flying west, you decelerate—compass shows turn toward south.”

17. Present VOR system operation using sectional chart and approach plate. Explain VOR provides magnetic bearing to/from station, CDI shows deviation from selected course (full-scale = 10°). Demonstrate OBS usage: “Rotate OBS until CDI centers with TO flag—that radial is your bearing TO the station. Rotate 180° for the radial FROM the station.”

18. Teach VOR check requirements per 14 CFR §91.171—every 30 days for IFR, logged in aircraft records or pilot logbook. Review methods: VOT (±4°), ground checkpoint (±4°), airborne checkpoint (±6°), dual VOR cross-check (±4°), or selected radial over landmark (±6°). State: “This isn’t optional for IFR—if your VOR is out of date on checks, it’s not legal for IFR navigation.”

19. Explain DME operation and interpretation—provides slant-range distance in nautical miles. Demonstrate calculation of groundspeed-derived time-to-station. Explain slant-range error: “At altitude directly over DME station, your DME will read your altitude converted to nautical miles (6,000 ft ≈ 1 NM). For helicopters flying low, slant-range error is usually negligible.”

20. Describe ILS components in detail—localizer provides lateral guidance (centerline), glideslope provides vertical guidance (typically 3°). Explain localizer width varies by runway length (700 ft at threshold) but angular width is constant (full-scale = 2.5° each side). Explain glideslope is narrower (0.7° full-scale = 1.4° total) and more sensitive than localizer.

21. Demonstrate ILS needle interpretation using approach plate and HSI/CDI diagram. Explain fly-toward-the-needle technique: “Localizer needle right = fly right to intercept centerline. Glideslope needle up = you’re below glideslope, climb or reduce descent rate.” Emphasize reverse sensing if inbound course set incorrectly on OBS.

22. Teach helicopter-specific ILS considerations—slower airspeeds improve tracking precision but increase wind drift susceptibility; lack of autopilot in most training helicopters means continuous manual control throughout approach; missed approach climb performance may be limited, requiring early decision at DA. State: “In a helicopter ILS, you’re hand-flying a very sensitive system at low airspeed—small corrections, smooth control inputs, and constant scan.”

23. Explain marker beacon system (if installed in training helicopter)—OM (blue/low tone) typically at glideslope intercept, MM (amber/medium tone) at approximate DA for Category I approaches. State: “Many ILS approaches no longer have marker beacons—they’ve been replaced with DME fixes or GPS-derived waypoints on RNAV overlay approaches.”

24. Present GPS operation principles—satellite-based positioning using trilateration from 4+ satellites. Explain RAIM (Receiver Autonomous Integrity Monitoring) checks signal integrity and is required for IFR unless WAAS-equipped. Demonstrate how to check RAIM availability for flight using flight planning software or GPS unit RAIM prediction function.

25. Explain GPS approach types using sample approach plates:

• LNAV: Lateral navigation only, non-precision MDA (e.g., 500 ft HAT)
• LNAV/VNAV: Adds advisory vertical guidance, lower minimums (e.g., 350 ft HAT)
• LPV: WAAS-enabled precision-like vertical guidance, lowest minimums (e.g., 250 ft HAT)—comparable to ILS but not technically “precision approach”
• LP: Lateral precision without vertical—rare, used where terrain prevents vertical guidance

26. Describe WAAS benefits—ground stations monitor GPS signals, calculate corrections, broadcast via geostationary satellites. WAAS improves GPS accuracy from ~100 meters to <3 meters (typically <1 meter), enables LPV approaches. State: “WAAS transformed helicopter IFR—thousands of airports now have precision-like approaches without ILS. For single-pilot helicopters, this is a game-changer.”

27. Teach GPS mode awareness—en route (±2 NM), terminal (±1 NM), approach (±0.3 NM)—sensitivity increases automatically as you near destination. Explain GPS automatically sequences waypoints and transitions between modes, but pilot must verify proper sequencing. Demonstrate how to activate approach mode and verify course guidance.

28. Explain GPS database currency requirements per 14 CFR §91.175 and AC 90-108—current database (updated every 28 days) required for flying GPS approaches. Emphasize: “You can use an expired database for en route navigation, but NOT for approaches. If database is expired, you can fly the approach only if you independently verify all data (courses, waypoints, minimums) match a current published approach plate.”

29. Demonstrate GPS failure modes—loss of RAIM, insufficient satellites, “LOI” (loss of integrity) message. Explain immediate action: if GPS fails during approach, execute missed approach unless visual with runway environment; request radar vectors or proceed to alternate navigation source (VOR).

30. Discuss autopilot systems (if applicable)—explain that most piston training helicopters (R22, R44, Schweizer 300) have NO autopilot, but turbine helicopters may have 2-axis or 3-axis autopilots. Describe typical modes: HDG (heading hold), ALT (altitude hold), NAV (VOR/GPS tracking), APP (approach mode). Emphasize disconnect procedures and importance of manual flight proficiency: “Never become dependent on automation—practice hand-flying regularly so autopilot failure doesn’t create an emergency.”

31. Teach automation monitoring principles (IH.II.B.R1)—maintain mode awareness (know what mode autopilot/GPS is in at all times), brief expected automation behavior before each flight segment, immediately disconnect automation if it behaves unexpectedly, minimize programming below 10,000 ft or inside FAF. State: “Automation is a tool to reduce workload, not a replacement for flying skills. If you’re spending more time programming the GPS than flying the helicopter, you’re doing it wrong.”

32. Explain EFB types and limitations—Type A (portable consumer device) most common in helicopter training. Review approved vs. non-approved distinction: portable EFB is NOT approved for IFR navigation; may be used for charts, weather, flight planning only. Demonstrate EFB features: geo-referenced approach plates, synthetic vision, traffic overlay, weather.

33. Teach EFB risk management (IH.II.B.R4)—battery depletion (carry backup battery or paper charts), overheating in direct sunlight, software crashes, database expiration. Best practices: fully charge before flight, reduce screen brightness to extend battery, verify chart dates are current, secure mounting to prevent control interference, have paper backup for critical approach plates.

34. Demonstrate approved vs. non-approved navigation devices (IH.II.B.R2) using panel-mounted GPS and portable GPS side-by-side. Explain: “This panel-mounted GPS is TSO-certified and approved for IFR navigation—it’s your primary navigation source. This iPad with GPS is NOT approved—it provides situational awareness only. You cannot legally fly an IFR GPS approach using the iPad, even if it shows the same magenta line.”

35. Review failure mode recognition (IH.II.B.R3)—how to identify instrument failures (erratic indications, flags, cross-check with other instruments). Practice scenario: “Your attitude indicator shows 20° bank but turn coordinator shows level—which is failed? Compare with GPS track and magnetic compass. If attitude indicator gyro failed, it shows false bank. Revert to turn coordinator and standby attitude indicator.”

36. Conduct cockpit demonstration in helicopter or training device—have student physically identify each instrument and navigation component: pitot tube, static ports, circuit breakers, avionics master, transponder, GPS, VOR/ILS controls, heading indicator adjustment knob, altimeter Kollsman window, magnetic compass, standby instruments (if equipped).

37. Demonstrate instrument cross-check technique—show how to verify instrument accuracy by comparing related instruments: airspeed vs. GPS groundspeed (corrected for wind), altimeter vs. GPS altitude, heading indicator vs. magnetic compass, attitude indicator vs. turn coordinator in turns.

38. Practice emergency procedures—demonstrate actions for alternator failure (shed electrical load, advise ATC, plan to land), pitot blockage (use GPS for speed reference), static blockage (use alternate static source), GPS failure (revert to VOR or request vectors), attitude indicator failure (use turn coordinator and compass).

39. Review regulatory compliance—14 CFR §91.171 (VOR checks), §91.205 (required equipment for IFR), §91.411 (altimeter/static system inspections), §91.413 (transponder inspections). Emphasize these are not optional and apply to all IFR operations including helicopters.

40. Conduct comprehensive oral questioning covering all knowledge elements—pitot-static system operation, gyroscopic principles, GPS approach types, VOR check requirements, compass errors, transponder modes, ADS-B requirements, EFB limitations, automation monitoring, database currency. Provide immediate feedback and correction of misconceptions.

41. Assign scenario-based evaluation—present failure scenario (e.g., “You’re on an ILS approach and your attitude indicator begins precessing—what are your immediate actions, what instruments do you rely on, and when do you execute missed approach?”). Evaluate student’s problem-solving and risk management decision-making.

42. Summarize key learning points at lesson conclusion—emphasize that thorough knowledge of instruments and navigation systems is foundational for safe single-pilot helicopter IFR operations, where workload is high and automation often limited or absent. Preview next lesson (basic attitude instrument flying).

Student Actions

1. Listen actively during instructor presentations, take notes on instrument systems, navigation equipment operation, and failure modes—organize notes by ACS task knowledge elements (K1a through K3).

2. Ask clarifying questions whenever instrument operation, error sources, or regulatory requirements are unclear—take responsibility for understanding rather than passively receiving information.

3. Participate in whiteboard exercises—draw pitot-static system schematic when requested, label gyroscopic instrument components, sketch ILS localizer/glideslope geometry to demonstrate understanding.

4. Study approach plates provided by instructor—identify localizer/glideslope frequencies, courses, minimums (LNAV, LNAV/VNAV, LPV), and differences between GPS and ILS approaches to same runway.

5. Review helicopter POH/AFM for training aircraft—identify electrical system schematic, circuit breaker locations, avionics descriptions, limitations, and emergency procedures for instrument/navigation system failures.

6. Practice instrument identification in cockpit or training device—accurately point to and name each component (pitot tube, static port, attitude indicator, heading indicator, turn coordinator, altimeter, airspeed indicator, VSI, VOR/ILS controls, GPS unit, transponder, magnetic compass, circuit breakers).

7. Demonstrate instrument setting procedures—set altimeter using Kollsman window, align heading indicator to magnetic compass (on east/west heading in straight-and-level flight), enter transponder code, set VOR frequency and identify station using Morse code or identifier.

8. Operate GPS/navigation system—demonstrate direct-to navigation entry, flight plan loading, approach selection and activation, CDI sensitivity verification, database expiration date check, RAIM status check (if non-WAAS GPS).

9. Interpret CDI indications—correctly state aircraft position relative to VOR radial, localizer centerline, or GPS course; determine corrections needed to intercept course; explain TO/FROM flag indications and reverse sensing scenarios.

10. Explain failure mode recognition—describe symptoms of pitot blockage, static blockage, gyro failure, GPS LOI, electrical failure; state backup instruments and procedures for each failure mode per POH/AFM.

11. Demonstrate compass error calculation—using compass correction card, determine magnetic heading for given compass heading; explain when compass indications are reliable and when they are not (ANDS/UNOS errors).

12. Practice EFB operation (if student uses EFB)—demonstrate chart navigation, approach plate display, geo-referencing, weather overlay, flight plan entry, database update check; explain limitations and backup procedures if EFB fails.

13. Answer instructor oral questions—provide accurate, complete answers regarding pitot-static system, gyroscopic instruments, GPS approach types, VOR check requirements, ILS components, transponder inspections, ADS-B requirements, automation monitoring, database currency.

14. Complete scenario-based problems—when presented with system failure scenario, correctly identify failed system, state immediate actions, determine alternate instruments/navigation sources, and explain regulatory implications (e.g., can you continue approach after GPS failure?).

15. Demonstrate cross-check technique—show instructor how to verify instrument accuracy by comparing related instruments (airspeed vs. GPS groundspeed, altimeter vs. GPS altitude, heading indicator vs. compass).

16. Review and self-assess understanding of all lesson content—identify weak areas and request additional explanation or practice; acknowledge proficiency when completion standards are met.

Completion Standards

The lesson is complete when the student demonstrates mastery of ACS Task IH.II.B to the following standards:

Knowledge (IH.II.B.K1-K3):

1. Accurately explains pitot-static system operation, including identification of pitot tube, static port(s), and connections to airspeed indicator, altimeter, and VSI—describes errors (position, density, temperature) and blockage scenarios with correct instrument indications for each scenario.
2. Describes gyroscopic principles (rigidity in space, precession) and operation of attitude indicator, heading indicator, and turn coordinator—identifies errors, limitations, and precession rates; explains setting procedures for heading indicator alignment with magnetic compass.
3. Explains electrical system architecture specific to training helicopter, including power sources, essential/non-essential buses, and battery backup duration—describes PFD/MFD operation, reversionary modes, and standby instrument use.
4. Accurately describes transponder operation (Mode A/C/S), required inspections per 14 CFR §91.413 (24 calendar months), and ADS-B Out requirements per 14 CFR §91.225—correctly states special transponder codes (1200, 7500, 7600, 7700).
5. Explains magnetic compass construction, operation, and errors—correctly applies ANDS (Accelerate North Decelerate South) and UNOS (Undershoot North Overshoot South) mnemonics; uses compass correction card to determine magnetic heading from compass heading.
6. Describes VOR system operation, CDI interpretation (full-scale deflection = 10°), TO/FROM indications, and reverse sensing—states VOR check requirements per 14 CFR §91.171 (30 days, tolerances for each method: VOT ±4°, ground checkpoint ±4°, airborne checkpoint ±6°, dual VOR ±4°, radial over landmark ±6°).
7. Explains ILS components (localizer, glideslope, marker beacons), including frequencies, sensitivities (localizer full-scale ≈ 2.5° each side, glideslope full-scale ≈ 0.7° each side), and typical glideslope angle (3°)—describes helicopter-specific ILS considerations (manual flight workload, airspeed management, missed approach performance).
8. Accurately describes GPS operation principles, RAIM requirements, WAAS benefits, and GPS approach types (LNAV, LNAV/VNAV, LPV, LP) with typical minimums—states database currency requirements per 14 CFR §91.175 (28-day cycle, current database required for approaches).
9. Explains GPS mode transitions (en route ±2 NM, terminal ±1 NM, approach ±0.3 NM for LNAV), automatic waypoint sequencing, and approach activation procedures—describes failure indications (loss of RAIM, insufficient satellites, LOI message) and required immediate actions.
10. Describes autopilot modes (if applicable to training helicopter) including engagement/disengagement procedures, disconnect methods, and limitations—acknowledges most piston training helicopters lack autopilot and explains implications for single-pilot IFR workload.
11. Explains EFB types (Type A portable, Type B mounted, Type C installed), features (geo-referenced charts, weather, traffic), limitations (non-approved for IFR navigation), and risk management (battery life, overheating, database currency, paper backup requirements).

Risk Management (IH.II.B.R1-R5): 12. Demonstrates understanding of automation monitoring principles—states importance of mode awareness, immediate disconnect if automation behaves unexpectedly, and maintaining manual flight proficiency; acknowledges automation complacency risks. 13. Correctly distinguishes between approved and non-approved navigation devices—states that only TSO-certified, installed GPS may be used for IFR navigation; portable GPS and EFB provide situational awareness only and are not legal for IFR navigation. 14. Identifies failure modes for pitot-static system (blocked pitot, blocked static), gyroscopic instruments (tumbling, precession), GPS (loss of RAIM, insufficient satellites), and electrical system (alternator failure)—states immediate actions, alternate instruments, and regulatory implications for each failure. 15. Explains EFB risk management practices including battery backup, mounting security, brightness adjustment, database currency verification, and paper chart backup for critical approach plates. 16. States GPS database currency requirements and risks of using expired database—correctly explains that expired database may be used en route but NOT for approaches unless procedure independently verified against current published approach plate.

Skills (IH.II.B.S1-S2): 17. Accurately identifies and locates all instruments and navigation equipment in helicopter or training device—pitot tube, static port(s), attitude indicator, heading indicator, turn coordinator, altimeter (Kollsman window), airspeed indicator, VSI, magnetic compass, VOR/ILS controls, GPS unit, transponder, PFD/MFD (if equipped), circuit breakers, electrical switches. 18. Demonstrates correct operation of altimeter (sets local altimeter setting via Kollsman window to within 0.01” Hg of provided value), heading indicator (aligns with magnetic compass on east/west heading to within ±3°), transponder (enters assigned code, verifies Mode C altitude reporting ON). 19. Operates VOR system by selecting frequency, identifying station using Morse code audio identifier or visual identifier, setting OBS to intercept desired radial, interpreting CDI deflection (correctly determines aircraft position relative to radial and required heading correction). 20. Operates GPS/navigation system by entering direct-to destination, loading flight plan, selecting and activating approach procedure, verifying appropriate CDI sensitivity, checking database expiration date—all actions performed correctly per avionics operating manual without instructor assistance. 21. Demonstrates GPS approach activation—loads approach, verifies approach type (LNAV, LNAV/VNAV, LPV), confirms GPS transitions to approach mode (±0.3 NM sensitivity), states minimums from approach plate matching GPS approach type. 22. Interprets CDI correctly for VOR, ILS, and GPS—states aircraft position (left/right of course), required correction, and fly-to intercept heading; correctly identifies reverse sensing condition and explains how to avoid it (set inbound course on OBS). 23. Demonstrates cross-check technique—compares airspeed indicator with GPS groundspeed (accounts for wind), altimeter with GPS altitude (within ±100 ft), heading indicator with magnetic compass (within ±5° on east/west heading), attitude indicator with turn coordinator in turn (verifies bank direction matches). 24. Operates EFB (if used)—demonstrates chart display, approach plate retrieval, geo-referenced position verification, weather overlay; verifies database currency (chart cycle date matches current AIRAC cycle); explains limitations and backup procedures. 25. Recognizes instrument failures when presented with simulated failure scenarios—correctly identifies failed instrument based on cross-check with other instruments, states alternate instruments to use, and explains required actions per POH/AFM (e.g., alternator failure: shed electrical load, advise ATC, plan to land ASAP).

Overall Performance:

• Student answers all instructor questions regarding instrument and navigation system operation, errors, limitations, and regulations with at least 80% accuracy and corrects any errors when prompted.
• Student locates and operates all instruments and navigation equipment in helicopter or training device without instructor assistance after initial demonstration.
• Student demonstrates complete understanding of helicopter-specific IFR considerations: high single-pilot workload, limited or absent automation, manual flight requirements, approach airspeed management, and risk management for system failures in IMC.
• Student acknowledges readiness to proceed to basic attitude instrument flying lessons, with full understanding that mastery of instrument/navigation systems is foundational for all subsequent instrument flight training.

Instructor Evaluation: The instructor confirms the student meets ACS Task IH.II.B standards by observing accurate explanations of all knowledge elements, appropriate risk management awareness, and correct demonstration of skills. Any deficiencies are identified, remedial instruction provided, and re-evaluation conducted until standards are met.