Navigation Systems and Radar Services

Objective

Upon completion of this lesson, the student will demonstrate the ability to use navigation systems and radar services in helicopter operations per FAA-S-ACS-15 PH.VII.B. The student will identify and operate ground-based and satellite-based navigation systems, utilize radar services and transponder equipment, maintain aircraft position awareness, and execute navigation tasks while maintaining altitude ±200 feet and heading ±15°.

Content

Ground-Based Navigation Systems (PH.VII.B.K1)

VHF Omnidirectional Range (VOR) VOR stations transmit signals on frequencies between 108.00-117.95 MHz. Per 14 CFR 91.171, VOR equipment must be checked within 30 days if used for IFR flight. For VFR operations, regular checks ensure accuracy.

VOR identification occurs through Morse code identifiers broadcast every 10 seconds. A missing or incorrect identifier indicates the station is unreliable. Course determination uses the Course Deviation Indicator (CDI) and Omni Bearing Selector (OBS). The CDI shows whether you’re left or right of the selected course, while the TO/FROM flag indicates your position relative to the station.

Think of VOR like a bicycle wheel - the hub is the station, and 360 spokes represent the radials extending outward. Your helicopter’s position is somewhere along one of these spokes.

Distance Measuring Equipment (DME) DME operates by sending interrogation signals to ground stations, receiving replies, and calculating distance based on signal travel time. DME provides slant range distance, not ground distance, creating slight inaccuracies at close range and high altitude.

Automatic Direction Finder (ADF) ADF points toward Non-Directional Beacons (NDB) regardless of aircraft heading. The needle shows relative bearing to the station. ADF is susceptible to interference from thunderstorms, mountains, and coastal refraction effects, especially at night.

Satellite-Based Navigation (PH.VII.B.K2)

Global Positioning System (GPS) GPS provides worldwide position, velocity, and time information using a constellation of at least 24 satellites. Per 14 CFR 91.205, GPS equipment must meet Technical Standard Order (TSO) requirements for aviation use.

Database currency is critical - navigation databases must be current per 14 CFR 91.13. Expired databases may contain obsolete waypoint information, creating hazardous navigation errors.

Receiver Autonomous Integrity Monitoring (RAIM) RAIM uses satellite geometry and signal redundancy to detect GPS errors. With fewer than 5 satellites in view, RAIM may not function, compromising navigation integrity. The GPS unit will typically display “RAIM NOT AVAILABLE” warnings.

Radar Services for VFR Aircraft (PH.VII.B.K3)

VFR Radar Advisory Service Approach control and departure control provide traffic advisories, safety alerts, and limited radar vectoring for VFR aircraft on a workload-permitting basis. Services include traffic advisories using clock positions and altitude (e.g., “Traffic 2 o’clock, 3 miles, southbound, altitude unknown”).

Flight Following VFR flight following provides continuous radar monitoring and traffic advisories. Request flight following by stating: aircraft type and identifier, position, altitude, destination, and request for flight following.

Transponder and ADS-B (PH.VII.B.K4)

Transponder Modes

• Mode A: Transmits 4-digit squawk code for aircraft identification
• Mode C: Transmits altitude information from encoding altimeter
• Mode S: Enhanced system providing discrete aircraft addressing and data link capability

Per 14 CFR 91.215, transponders are required in Class A, B, and C airspace, and above 10,000 feet MSL (excluding airspace below 2,500 feet AGL).

Automatic Dependent Surveillance-Broadcast (ADS-B) Per 14 CFR 91.225, ADS-B Out is required in the same airspace requiring transponders, effective January 1, 2020. ADS-B broadcasts aircraft position, altitude, velocity, and identification to ground stations and other aircraft.

Risk Management

Management of Automated Systems (PH.VII.B.R1) Automation can reduce workload but creates complacency risks. Always maintain manual navigation skills as backup. Cross-check GPS positions with ground references and other navigation aids. Think of GPS as an incredibly accurate co-pilot, but you remain the pilot-in-command making navigation decisions.

Distractions and Situational Awareness (PH.VII.B.R2) Navigation system programming requires heads-down time, creating collision risks. Brief passengers about sterile cockpit procedures during navigation tasks. Use clearing turns before extended heads-down periods. Prioritize tasks: aviate, navigate, communicate.

System Limitations (PH.VII.B.R3) Each navigation system has specific limitations:

• VOR: Limited range at low altitudes due to line-of-sight requirements
• GPS: Signal blockage in canyons or near tall buildings
• ADF: Interference from weather and terrain
• DME: Slant range errors at close distances

Signal Loss Procedures (PH.VII.B.R4) Develop contingency plans for navigation failure. Always carry current sectional charts and maintain pilotage skills. If GPS fails, immediately revert to ground reference navigation and contact ATC if receiving flight following.

Electronic Flight Bag Usage (PH.VII.B.R5) EFBs provide excellent situational awareness but require proper mounting, backup power, and current database subscriptions. Per Advisory Circular AC 91-78, EFBs are considered electronic devices subject to 14 CFR 91.21 portable electronic device regulations.

Schedule

Equipment

Required References:

• FAA-H-8083-21B Helicopter Flying Handbook
• FAA-H-8083-25B Pilot’s Handbook of Aeronautical Knowledge
• FAA-S-ACS-15 Private Pilot Helicopter Airman Certification Standards
• Current Sectional Aeronautical Chart
• 14 CFR Parts 61, 91

Materials:

• Aircraft with operational navigation equipment (VOR, GPS, transponder)
• Aviation headset with intercom capability
• Current Airport/Facility Directory
• Navigation log sheets
• Flight computer or electronic calculator

Visual Aids:

• VOR/GPS navigation system diagrams
• Transponder control panel examples
• ADS-B system overview charts
• Radar service area maps

Instructor Actions

1. Brief the student on lesson objectives and explain how navigation systems enhance flight safety while requiring proper management to avoid over-reliance on automation.

2. Demonstrate VOR system operation by tuning a local VOR station, identifying the station using Morse code, and showing how to determine aircraft position using radial information.

3. Explain VOR course interception by setting up a practice intercept, demonstrating the relationship between CDI deflection, aircraft heading, and desired course.

4. Show GPS system startup procedures, database currency verification, and basic navigation functions including direct-to navigation and flight plan entry.

5. Demonstrate RAIM checking procedures and explain what actions to take when RAIM is unavailable or when GPS navigation becomes unreliable.

6. Practice requesting VFR radar advisory service using proper phraseology: “Approach Control, Helicopter 123AB, 15 miles south of Metro Airport, 2,500 feet, VFR to Mountain View Airport, request flight following.”

7. Explain transponder code setting procedures and demonstrate Mode C altitude verification by comparing transponder readout with aircraft altimeter.

8. Show ADS-B system operation and explain how it provides traffic information and weather data to equipped aircraft.

9. Demonstrate navigation system failure recognition and appropriate response procedures, emphasizing the importance of maintaining visual navigation skills.

10. Guide the student through a complete navigation scenario combining multiple systems while maintaining proper altitude and heading control.

Student Actions

The student will tune and identify VOR stations, demonstrate understanding of radial concepts, and show proper use of CDI and OBS controls for navigation. The student will operate GPS equipment including waypoint entry, direct-to navigation, and flight plan execution while maintaining awareness of database currency requirements.

The student will request and utilize VFR radar advisory services using appropriate communication procedures and phraseology. The student will demonstrate proper transponder operation including code setting and Mode C verification procedures.

The student will recognize navigation system malfunctions or signal loss and execute appropriate contingency procedures. Throughout all navigation tasks, the student will maintain assigned altitude ±200 feet and heading ±15° while demonstrating proper task prioritization and situational awareness.

Completion Standards

The student demonstrates satisfactory performance per FAA-S-ACS-15 PH.VII.B when able to:

Knowledge Standards:

• Explain ground-based navigation system operation, limitations, and regulatory requirements per PH.VII.B.K1
• Describe GPS principles, RAIM functionality, and database requirements per PH.VII.B.K2
• Identify available radar services and proper communication procedures per PH.VII.B.K3
• Explain transponder modes and ADS-B requirements per PH.VII.B.K4

Risk Management Standards:

• Demonstrate proper automated system management without over-reliance per PH.VII.B.R1
• Show effective task prioritization and maintain situational awareness per PH.VII.B.R2
• Identify and explain navigation system limitations per PH.VII.B.R3
• Execute appropriate signal loss procedures per PH.VII.B.R4
• Demonstrate proper EFB usage if applicable per PH.VII.B.R5

Skill Standards:

• Operate airborne electronic navigation systems effectively per PH.VII.B.S1
• Determine aircraft position accurately using available navigation systems per PH.VII.B.S2
• Intercept and track courses, radials, or bearings within ±10° per PH.VII.B.S3
• Recognize and describe station or waypoint passage indications per PH.VII.B.S4
• Identify navigation signal loss and execute proper procedures per PH.VII.B.S5
• Use correct phraseology and procedures when utilizing radar services per PH.VII.B.S6
• Maintain altitude ±200 feet and heading ±15° throughout navigation tasks per PH.VII.B.S7