CPL Navigation and Radio Aids 2 — Questions and Answers
Question 1: What does a VOR receiver indicate when the aircraft is directly over the station in the cone of silence?
- The CDI centers with a TO flag
- The CDI centers with a FROM flag
- The TO/FROM indicator fluctuates and the CDI swings erratically (Correct answer)
- The OFF flag appears and the CDI deflects fully left
Correct answer: The TO/FROM indicator fluctuates and the CDI swings erratically
In the cone of silence directly overhead a VOR, the weak signal causes the TO/FROM flag to fluctuate and the CDI to swing erratically.
Question 2: DME slant range error is most significant when the aircraft is:
- At low altitude and far from the station
- At high altitude and far from the station
- At high altitude and close to the station (Correct answer)
- At low altitude and close to the station
Correct answer: At high altitude and close to the station
At high altitude and close to the station, the aircraft's vertical distance represents a large fraction of the slant range, making the error between slant range and ground distance greatest.
Question 3: While flying outbound on the 180° radial (OBS 180°, FROM indication), the CDI deflects to the left. To intercept the 180° radial, the pilot should turn:
- Right
- Left (Correct answer)
- To heading 000°
- The CDI shows reverse sensing; turn right
Correct answer: Left
With a FROM indication and normal (outbound) sensing, the CDI deflects toward the course; the pilot turns left toward the needle to intercept.
Question 4: The FAA-permitted tolerance for an airborne VOR receiver check over a designated checkpoint is:
- ±2°
- ±4° (Correct answer)
- ±6°
- ±10°
Correct answer: ±4°
FAR 91.171 requires VOR airborne receiver check accuracy to be within ±4° of the published radial for the designated checkpoint.
Question 5: While flying a constant heading, an aircraft crosses the 350° radial then the 020° radial of a VOR in 2 minutes. Approximately how many minutes away is the station?
- 4 minutes (Correct answer)
- 6 minutes
- 12 minutes
- 20 minutes
Correct answer: 4 minutes
Time to station = (minutes elapsed × 60) ÷ degrees of bearing change = (2 × 60) ÷ 30 = 4 minutes.
Question 6: A High altitude VOR (HVOR) provides reliable signal service up to:
- 40 NM at all altitudes
- 100 NM from the surface to 18,000 ft MSL
- 130 NM between 14,500 ft MSL and FL600 (Correct answer)
- 200 NM above FL450
Correct answer: 130 NM between 14,500 ft MSL and FL600
An HVOR service volume extends 130 NM laterally between 14,500 ft MSL and FL600, supporting high-altitude en route navigation.
Question 7: VOR course scalloping (rapid CDI oscillation at a specific location) is most commonly caused by:
- Low battery voltage in the aircraft receiver
- Multipath signal reflections from terrain or structures near the VOR station (Correct answer)
- Aircraft flying above the published service volume
- Magnetic variation differences between the aircraft and the station
Correct answer: Multipath signal reflections from terrain or structures near the VOR station
Scalloping is caused by multipath interference — reflected VOR signals from nearby terrain, buildings, or structures that arrive slightly out of phase with the direct signal.
CPL Navigation and Radio Aids 2
What does a VOR receiver indicate when the aircraft is directly over the station in the cone of silence?