Diverting to an alternate destination

A diversion = destination changed in flight (e.g. deteriorating weather, sick passenger, aircraft problem).

Steps:

1. Choose alternate: suitable destination, suitable distance, suitable terrain.
   • Line feature leads there (road, powerline, railroad, river, shoreline): follow it. Simplest, recommended.
   • No usable line feature: draw free-hand track line. Break long diversion into shorter legs.
2. Start from a known fix: positively identified point, not an estimated position.
3. Estimate heading (TP 1102, Estimate Heading):
   • Many pilots assume track = heading, set it, then apply drift compensation method once established.
   • Wind already known strong: estimate and apply drift correction up front, adjust as needed.
4. Recompute once established: note time, use nearest winds aloft for new heading and ground speed, then arrival time and fuel consumption (TP 1102 log: new ground speeds, revised ETAs; PHAK ch.16).
5. Arrive at alternate (TP 1102 Low Level Navigation):
   • Do not interfere with other traffic.
   • Alternate in Control Zone: normal zone-entry requirements and procedures.
   • Uncontrolled airport: correct circuit-joining procedure.

Emergency (PHAK ch.16): divert promptly. Turn toward alternate first. Full plot, measurement and computation before turning only prolongs it.

Trap: diverting without telling ATC (or responsible person) the new destination: any search still targets the original filed route.

Practice