Aviation Radio Navigation System Quiz

Early Airline Flights

• First scheduled airline flight in the US occurred just before WWI
• St. Petersburg–Tampa Airboat Lines operated for three months in 1914
• The airline folded due to lack of passengers during the spring
• Federal government sold surplus military aircraft after WWI.
• These inexpensive aircraft helped launch the aviation industry.
• Post Office Department used Army aircraft to establish the first official airmail service in 1918.

Airline Industry Stabilization

• The Post Office Department contracted airmail routes to struggling airlines
• Airlines used airmail contracts to subsidize passenger fares
• Airlines then bought larger, more luxurious, passenger aircraft
• Airline scheduling and operations became complex, as passenger and mail services were combined.
• Airlines needed methods for poor weather and night flying to survive and prosper.

Visual Navigation

• Early pilots relied on visual references like the horizon to navigate.
• Pilotage used maps and landmarks for navigation
• Crosswind correction was needed for constant course alteration.
• Road maps inappropriate for aerial navigation, Sectional charts were created for accuracy (about 8 statutory miles per inch).

Aeronautical Charts

• Sectional charts display relevant information for safe navigation
• Key elements on sectional charts include: cities, highways, railroads, airports, terrain features, and distinctive objects, federal airways, and air traffic control facilities.
• The sectional charts are scaled at a ratio of 1:500,000, which is approximately 8 statute miles per inch.
• A legend for the charts is included for easy interpretation.

Dead Reckoning and Flight Planning

• Dead Reckoning uses forecasted winds at cruising altitude alongside calculations to predict the angle of heading an aircraft must fly to counteract crosswinds.
• A sectional chart is crucial to verify the reliability of dead reckoning
• The first step in flight planning involves determining the true course, measuring its angle relative to the true north (via a device known as a plotter) and subsequently calculating the correct aircraft heading.

Aircraft Instrumentation

• Magnetic compasses indicate the heading relative to magnetic north and require pilots to account for the variation from magnetic to true north to use the information correctly.
• Variation differs at different locations.
• Heading indicator(a gyroscopic instrument) also displays direction without inaccuracies related to acceleration or turning errors and stray magnetic fields.
• However, it does require initial calibration by the pilot.

VFR Navigation

• Pilotage and dead reckoning are used for VFR navigation
• Airport and airway lighting were crucial for night and marginal weather
• Initial airport boundary lighting used 40 watt lights on wooden stakes around the runway perimeter.
• Rotating airway beacons provided consistent location cues for pilots.
• The beacons were set up at intervals along the airway and emitted a white light for visibility.
• Airport beacons are equipped with a green or a white lens.

Instrument Flying

• Attitude indicator, heading indicator, and the turn coordinator allow pilots to control their aircraft without relying on visual references.
• Flight instruments provide accurate information regarding aircraft attitude, direction and rate of turn.
• Altimeter, airspeed (indicator) are used for further instrumentation
• Advancements and reliance on cockpit instrumentation for navigation, enabling safe flight in clouds and reduced visibility
• The attitude indicator mimics the natural horizon and displays aircraft attitude.
• The heading indicator is crucial for maintaining flight direction.
• The turn coordinator provides information on the direction and rate of turn.

Electronic Navigation

• Four-course radio ranges were installed in the late 1920s (operated in the 190–565 kHz frequency band)
• Radio ranges provided navigation without requiring visual aids.
• NDB (nondirectional radio beacons) are used for bearings
• N.DBs transmitters provide omni directional signals.
• NDBs used to be a more common navigation tool, however, with more modern navigation systems, it is less used now.

Introduction of Marker Beacons

• These low-powered radio beacons transmitted distinctive signals useful for precise navigation
• To determine their location along the course of an approach

Automatic Direction Finder

• The ADF is an electronic device
• The ADF automatically determines bearing to a beacon.
• ADF system displays this information for pilot use.

Compass Locators

• Compass locators are located at runways in order to guide pilots during instrument approaches.
• The location is determined through the use of high-powered NDBs for en-route navigation

Visual Aural Range

• VAR ( Visual Aural Range) was later developed with improvements over the A-N range
• VAR operated within the very high frequency (VHF) band, around 63 mHz
• The VAR used overlapping signals, unlike the A-N range, which enabled the pilot to more accurately determine aircraft location.

VHF Omnidirectional Range (VOR)

• VOR offered multiple courses via a single transmitter
• VHF signals are immune to static and obstructions

DME Position Determination

• DME (Distance Measuring Equipment) uses the time of flight of a signal for distance measurements
• A coded pulse is transmitted at a regular interval from the interrogator
• When received, the ground-based transponder replies with a coded pulse.
• The time difference between transmission and reception allows calculating the distance between the aircraft and the ground station.
• This information is essential for accurate position determination

Tactical Air Navigation (TACAN)

• TACAN provides both bearing and distance information (rho-theta) to pilots, particularly in military operations
• TACAN and VOR facilities are set in close proximity (VORTAC)
• VORTAC aids serve both military and civilian aircraft for navigation needs.

Global Navigation Satellite System (GNSS)

• GNSS ( Global Navigation Satellite Systems) comprises space-based satellite systems providing global navigation.
• The signals enable the determination of location (latitude, longitude, and altitude) via inexpensive receivers.
• GPS (Global Positioning System) is a fully operational GNSS system with 24 orbiting satellites

Receiver Autonomous Integrity Monitoring (RAIM)

• RAIM is a critical function for GPS receivers
• RAIM checks the accuracy and integrity of satellite signals

Wide Area Augmentation System (WAAS)

• WAAS corrects potential errors exhibited by satellite and ground based receivers.
• WAAS provides highly precise position information by using ground-reference stations.
• WAAS improves accuracy by a factor of 10 to give more precise GPS positioning.

Ground-Based Augmentation System (GBAS)

• GBAS is similar to WAAS except that the ground based transmitter gives the signal directly to the aircraft.

Inertial Navigation System (INS)

• INS uses accelerometers that measure minute changes in aircraft speed and direction.
• INS calculates speed, direction, and time of arrival.
• INS is independent of ground-based navigation stations
• INS calculations are highly accurate over long periods

Performance Based Navigation (PBN)

• PBN (performance-based navigation) is a framework
• PBN specifications are not based on equipment but rather on defined operational needs.
• PBN provides additional latitude for choice of equipment

Approach Navigation Waypoints

• GPS-based approaches involve fly-by and fly-over waypoints
• Fly-by waypoints define a route change
• Fly-over waypoints require traversing a specific point

Runway Lighting

• Runway lights provide nighttime visibility with visual cues to aid pilots
• Runway lights are critical for instrument approaches, especially in reduced visibility
• Different types of lights exist (Low intensity, Medium intensity, and High intensity).
• Embedded lights like touchdown zone lighting and runway centerline lights exist and complement visual aids for safer navigation

Test your knowledge on the VHF Omni-directional Range (VOR) and VHF navigation systems used in aviation. This quiz covers the benefits, functionality, and historical context of these technologies. Explore concepts such as rho-rho position determination and VOR airway designators.