radio.training

The PPL flight test diversion (Ex. 23D): heading, time and fuel in your head

What the flight test asks

Ex. 23D asks you to divert to an alternate using mental in-flight planning, dead reckoning, map reading and pilotage. Rulers, protractors, devices such as ForeFlight, computers and radio navigation aids are not used. Among the criteria: identify and record your present position, select an alternate, estimate an initial heading to fly direct based on a track line, estimate an approximate time en route, and estimate the flight time that will remain with the fuel on board on arrival.

The guide itself says this will require extensive ground training and practice. While you fly it, headings are held within 10 degrees and altitude within 200 feet.

A mental method

• Track: judge the line against the nearest meridian, which is true north. Round to 5 degrees.
• Drift: maximum drift is wind speed times 60, divided by true airspeed. Take a fraction of it by how far the wind is off your nose or tail: 15 degrees a quarter, 30 a half, 45 three quarters, 60 or more all of it. Point into the wind.
• Variation: east is least (subtract), west is best (add). That gives the magnetic heading.
• Groundspeed: true airspeed plus or minus the wind along your track, then distance divided by miles per minute.
• Fuel: time on board less time en route.

Tell ATS

Ex. 23D(h) asks you to simulate communication with ATS to inform them of your intention to divert. On a flight plan, the NAV CANADA guide's format is: call the flight information centre, say you are on a VFR flight plan from your origin to your destination and would like to make a change, then outline the change and a new ETA. The specialist repeats it back.

The diversion drill gives you a sketch, the wind and your airspeed over a real Fraser Valley call-up point, and checks your estimate, then shows the working.

Try the diversion drill → Read the nav log guide →