NDB approaches
The ADF needle, bearings, and the timed final segment -- flown on the real NDB RWY 31 chart into Peoria.
14 min read · Instrument approach systems
After this lesson you can
- Compute a magnetic bearing to a station from a magnetic heading and a relative bearing reading.
- Explain the difference between homing and tracking, and why homing produces a curved path in a crosswind.
- List at least three of the common pilot-induced errors that make ADF navigation difficult.
- Locate the LOM, the procedure turn, and the timed final segment on a real NDB approach chart.
Direction finding by radio is the oldest navigation technique still taught for an instrument rating, and the most disorienting one for a pilot raised on GPS: the instrument does not tell you where you are. It tells you, at that instant, which direction the station lies from the nose of the airplane, and nothing more. Everything else -- your position, your track, your correction for wind -- has to be built from that single number, continuously, by the pilot.
The number of installations keeps shrinking, but the reasoning behind the needle is still tested and still worth understanding, because it is the foundation for interpreting any bearing-pointer instrument. This lesson works the bearing math, the technique of tracking versus homing, the errors that catch nearly every pilot at least once, and a real chart: NDB RWY 31 into Peoria (PIA), where the same NDB serves as the outer locator, the initial approach fix, and the final approach fix, all at once.
The rest of this lesson
- 1.The station and the needle
- 2.Homing versus tracking
- 3.Intercepting a bearing
- 4.The errors that humble everyone
- 5.Reading it on the chart: NDB RWY 31, Peoria
- 6.What this NDB approach demands of the pilot
These 6 sections, their figures, the checks along the way and the end-of-lesson quiz come with the IFR track. Paid once, yours for good.
Key terms
Try to recall each definition before turning the card.