Lamberts and Mercator Plotting – Ibex Aviation Academy

Lamberts vs Mercator Plotting

Radio bearings can be plotted on Lambert Charts by following these steps
Step 1 – Convert Relative bearings to Magnetic Bearings
Formula for Magnetic bearings = Relative bearing + Magnetic heading
If the value of magnetic bearing is greater than 360 Subtract 360 from the result
Step 2 – Convert Magnetic bearings to the station (QDM) to Magnetic Bearings from the station (QDR)
Step 3 – Convert Magnetic Bearing (QDR) to True Bearings (QTE)
Get True Bearings by Applying Station Variation to Magnetic bearing in case of VOR Bearings
Get True Bearings by Applying Aircraft Variation to Magnetic bearing in case of ADF Bearings
Step 4 – Bearing to plot is obtained by applying calculated chart convergence
Alternately, the resultant bearing can be plotted from the false meridian at Ground station

Radio bearings can be plotted on Mercator Charts by following these steps
Radio signals from VDF, VOR or NDB take the great circle path to the aircraft
In the Mercator charts Rhumb lines are straight lines while great circles are curves
Therefore, the measured great circle bearings have to be converted to rhumb line directions for plotting on mercator chart
Step 1 – Apply conversion angle (1/2 convergency) at the end where bearing is measured for conversion from GC TO RL
Step 2 – For VOR and VDF (bearings measured at the station) apply variation and conversion angle at the station
Step 2A – For ADF or AWR (bearings measured at the aircraft) apply variation and conversion angle at the aircraft
Step 3 – Find the reciprocal and plot the reciprocal bearing from the ground station