Contents:?

1. ADF Equipment Operation

2. ADF Navigation Procedures

1. ADF Equipment Operation

• ADF: An Automatic Direction Finder (ADF) is a radio navigation system that indicates direction to low and medium frequency (LMF) tranmistting stations, including nondirectional beacons (NDBs) and AM commercial broadcast stations

• ADF System Equipment Operation

• Also limited to line of sight

• NDB stations: 190-535 kHz

• AM broadcast stations: 535-1705 kHz

• Should never rely on commercial broadcast stations for primary navigation, but they are useful as supplementary VFR navaids

• When you tune an NDB station, listen carefully to the Morse code identifier to be sure you are receiving the correct station

• Bearing and Relative Bearing

• Bearings are stated in degrees, measured clockwise from the nose of the aircraft

• An ADF bearing indicator gives you the relative bearing, or angle, between your airraft and the station

• ADF Bearing Indicators

• Fixed-card

• Zero (North) always appears at the top

• The numbers correspond to the stations bearing relative to the nose

• The head of the needle points to the relative bearing

• Movable-card

• You can rotate the azimuth card so the magnetic heading is at the top

• Radio magnetic indicator (RMI)

• The radio magnetic indicator automatically adjusts the azimuth card to show magnetic heading

• Interpret a Fixed-Card ADF Bearing Indicator

• Interpret a Movable-Card ADF Bearing Indicator

• Rotate the azimuth card so your heading appears at the top of the indicator

• Read the magnetic bearing to the station under the arrow

• Read the magnetic bearing from the station under the tail of the arrow
  

• Interpret a Radio Magnetic Indicator

• Automatically rotates the azimuth card to reflect the aircraft's magnetic heading

• Always displays the magnetic bearing to a station at the head of the arrow

• Always displays the magnetic bearing from a station at the tail of the arrow

2. ADF Navigation Procedures

• Homing to a Station

• Tune and identify the station

• Turn until the needle points to the top of the ADF bearing indicator

• Keep the needle aligned with the nose and fly toward the station

• A crosswind component causes your aircraft to drift off course; you must keep changing your heading to keep the aircraft's nose pointed toward the station