Radio Navigation Oral Questions

Question 1

How does Distance Measuring Equipment (DME) work?

Answer 1

It is normally tuned automatically with a
paired VHF station (VOR/LOC).

Then, the Airborne DME unit transmits an interrogation signal.

Then, the ground DME facility receives and replies to the interrogation.

Then, the Airborne unit calculates the slant range distance to the station based on the reply time.

Question 2

What is the indication, when overhead flying the station?

Answer 2

Due to slant range error, it does not indicate “0”.

Question 3

What is slant range negligible to? What is an example?

Answer 3

Slant range error is negligible at 1 NM from the DME station per every 1000ft.

For example, at 5000 ft, slant range error is negligible when further than 5 NM of the station.

Question 4

What is a compass locator? How many watts is it? What is the range? Where is it installed?

Answer 4

A low-powered NDB transmitter.

It has at least 25 Watts

It has a 15NM range

It is installed at the OM or the MM on some ILS approaches.

Question 5

What are some of the limitations of a VOR?

Answer 5

• Cone of Confusion
• Reverse Sensing (if used correctly)
• Requires line-of-sight between aircraft and station

Question 6

What must be logged on a VOR check?

Answer 6

D - Date
E - Error (bearing error)
P - Place
S - Signature

Question 7

What is RNAV? What does it enable?

Answer 7

• Area Navigation
• RNAV is a system that enables navigation between any two points without the need to overfly ground-based stations.

Question 8

What are the different types of Area Navigation?

Answer 8

• Global Navigation Satellite System (GNSS)
  (e.g., GPS)
• VOR/DME RNAV
• DME/DME RNAV
• Inertial Reference Unit / System (IRU/ IRS)

Question 9

What is BARO-VNAV?

Answer 9

• An RNAV system that uses the barometric altitude to compute vertical guidance for the pilot.

Question 10

What is the Magnetic Reference Bearing (MRB)?

Answer 10

• The published bearing between two waypoints on an RNAV route.

Question 11

What is Requiremed Navigational Performance (RNP)?

Answer 11

A statement of navigation equipment and service performance.

RNAV with navigation monitoring and alerting.

Question 12

What equipment is needed for LNAV/VNAV minimums?

Answer 12

• Decision Altitude is rachieved by VNAV-approved WAAS, or BARO- VNAV systems.

Question 13

What equipment is needed for LNAV minimums?

Answer 13

Minimum Descent Altitude is achieved by a basic, unaugmented IFR-approved GPS.

Question 14

What equipment is needed for LPV minimums?

Answer 14

• Decision Altitude minimums require RNP achieved by WAAS.

Question 15

What is GPS? Who is operated by?

Answer 15

GPS is a Global Navigation Satellite System (GNSS) operated by the United States.

Question 16

Explain GPS? How many satellites are there orbiting Earth? How many are in view at all times?

Answer 16

The constellation consists of a minimum of 24 satellites (with some spares) orbiting above the earth at 10,900 NM. The system is designed so that at least 5 satellites are in view at any given location on earth.

Question 17

How does the GPS receiver calculate the distance to the GPS satellite?

Answer 17

The Aircraft’s GPS receiver calculates the distance to a GPS satellite based on the time lapse since the broadcast timestamp (obtained from an atomic clock onboard the satellite) and the time it received the signal.

Question 18

What would happen if you only used one GPS satellite to locate yourself?

Answer 18

Using only one satellite, the aircraft could virtually be on any point on a sphere surrounding the satellite, with the calculated distance (“pseudo-range”) as the sphere’s radius.

Question 19

How does the GPS use the satellite receivers to calculate the geographical position? Furthermore, how is the course and speed data calculated?

Answer 19

The GPS receiver uses the intersection of spheres, from multiple satellites, to calculate the aircraft’s geographical position. Course and speed data are computed from aircraft position changes.

Question 20

How many satellites are required for 2D positioning (latitude and longitude)?

Answer 20

• 3 Satellites

Question 21

How many satellites are required for 3D positioning (latitude, longitude, and altitude)?

Answer 21

• At least 4 satellites

Question 22

What is RAIM? What does it monitor?

Answer 22

• Receiver Autonomous Integrity Monitoring
• It is a function of GPS receivers that monitors the integrity of the satellite signals.

Question 23

How many satellites does RAIM require to provide Fault detection? What if it doesn’t meet the minimum required satellites, then what will you need?

Answer 23

• RAIM requires a minimum of 5 satellites for fault detection

Or

• 4 satellites + an altimeter input (baro-aided RAIM)

Question 24

How many satellites are necessary to exclude a corrupt satellite?

Answer 24

For fault exclusion, RAIM needs a total of 6 satellites or 5 satellites + Baro-aid.

Question 25

What does the GPS CDI Deflection needle show?

Answer 25

Distance

Question 26

What does the VOR CDI needle show?

Answer 26

The angular distance off course

Question 27

What navigational equipment should you check before every IFR flight?

Answer 27

- Check GPS NOTAMS - Check available RAIM prediction on your receiver

Question 28

What are GPS Augmentation Systems? What are they measuring?

Answer 28

Improves the accuracy of GPS by measuring errors received by reference stations at known geographical locations and then broadcasting those errors to supported GPS receivers.

Question 29

What is WAAS? Where is located?

Answer 29

Wide Area Augmentation System - Europe - In the U.S.

Question 30

How does WAAS work?

Answer 30

Ground stations (Wide-area Reference Stations and Wide-area Master Stations) measure GPS errors and produce correction signals. These corrections are broadcasted back to the satellite segment from which they are bounced back to aircraft GPS WAAS receivers to improve accuracy, integrity and availability monitoring for GPS navigation.

Question 31

What is SBAS? What does it comprise of?

Answer 31

Satellite Based Augmentation System - WAAS - Covers a wide area - It facilitates APV approaches such as LPV and LNAV/VNAV and LP approaches.

Question 32

What is Performanced Based Navigation (PBN)?

Answer 32

PBN is a general basis for navigation equipment standards, in terms of accuracy, integrity, continuity, availability and functionality for specific operation contexts (e.g., final approach, enroute, missed approach).

Question 33

When navigating from VOR to VOR, when do you change frequencies to maintain course guidance?

Answer 33

At that point depicted on the airway as the changeover point In the absence of a changeover point, the halfway point on the airway Whenever there is a bend in an airway

Question 34

What are the dimensions of victor airways?

Answer 34

Victor airways begin at 1200’ AGL and extend up to 17,999’ MSL. The width is 8nm (4nm from each side of the centerline)

Question 35

What is DME? When is DME equipment required?

Answer 35

DME is distance measuring equipment. It is a separate ground station that may be collocated with a VOR, ILS, or localizer. It provides slant range distance in NM. When using VOR navigation above 24000, DME or a suitable RNAV system is required.

Question 36

How many degrees of deviation does each dot represent? What angular deviation from a VOR course is represented by half-scale deflection of the CDI?

Answer 36

Each dot represents 2° of deviation. Half scale deflection is 5° off course.

Question 37

Where can you find the location of airborne, ground and VOT testing stations?

Answer 37

Chart Supplement (see back cover)

Question 38

What are the different methods for checking the accuracy of VOR equipment?

Answer 38

VOT Ground Check Airborne Airway Dual VOR