6.50 Special Procedures

6.50.2 Describe the techniques and procedures for:  

(a) re-establishing position if lost or unsure of position; 

Estimate your most probable position (MPP) using:

• Time since last known position
• Heading flown
• Groundspeed (or airspeed if needed)

From this, draw a circle of uncertainty:

• Centre = DR position
• Radius increases with time (errors from wind/navigation)
• Moves along track if a steady heading is maintained
• Aircraft is likely displaced downwind, but could be anywhere in the circle

How to Fix Position

• Maintain a steady heading to prevent increasing uncertainty
• Observe ground features carefully (rivers, roads, towns, coastlines)
• Note their shape, direction, and sequence
• Compare what you see with the chart within the circle of uncertainty
• Match patterns to narrow down and establish a fix

Practical Techniques