Navigation and Radio Aids Flashcards
7 cards from real CPL practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Navigation and Radio Aids flashcards as text
When the ADF needle points to 000° on the relative bearing indicator, it means:
Answer: The NDB station is directly ahead of the aircraft
An ADF relative bearing of 000° indicates the NDB station is directly ahead of the aircraft, on the nose, regardless of magnetic heading.
What is the key difference between 'homing' and 'tracking' to an NDB?
Answer: Homing keeps the needle at 000° causing a curved ground path in crosswind; tracking applies a wind correction angle for a straight track
Homing points the aircraft directly at the station (ADF stays at 000°) but results in a curved, wind-drifted path; tracking applies a wind correction angle to maintain a straight ground track.
On an RMI (Radio Magnetic Indicator) with an ADF pointer, the TAIL of the needle indicates:
Answer: The magnetic bearing FROM the station
On an RMI, the head of the ADF pointer shows the magnetic bearing TO the station, and the tail shows the magnetic bearing FROM the station.
Which atmospheric phenomenon most severely degrades ADF/NDB accuracy?
Answer: Thunderstorms and precipitation static
Thunderstorms generate electromagnetic energy in the AM frequency band that attracts the ADF needle away from the NDB station, producing large bearing errors.
The 'night effect' on NDB signals causes bearing errors because:
Answer: The descending ionosphere at night causes sky waves to mix with ground waves, producing erroneous bearings
At night the ionosphere descends, allowing NDB signals to refract back to earth as sky waves that mix with the direct ground wave, causing bearing errors that worsen with distance.
An aircraft has a magnetic heading of 270° and an ADF relative bearing of 045°. The magnetic bearing TO the NDB station is:
Answer: 315°
Magnetic bearing to station = magnetic heading + relative bearing = 270° + 045° = 315°.
Why does an ADF receiver include a sense (omnidirectional) antenna in addition to the loop antenna?
Answer: To resolve the inherent 180° bearing ambiguity of the loop antenna alone
The loop antenna produces two nulls 180° apart with no way to distinguish which is correct; the sense antenna's phase comparison resolves the ambiguity to a single bearing.