Diversion
General
A diversion is a situation where the pilot decides to land the aircraft at a different aerodrome than originally planned.
Diversions can be divided into three broad groups:
- Air turnbacks: These are situations where the aircraft returns to the departure aerodrome.
- En-route diversions: These are situations where the aircraft diverts to an alternate before reaching the vicinity of the planned destination aerodrome.
- Destination diversions: These are situations where the aircraft diverts to an alternate after reaching the vicinity of the planned aerodrome.
Reasons for Diversions
Diversions can happen for many reasons, e.g.:
- Adverse weather (e.g. due to thunderstorms or significant crossing)
- Aerodrome closure (e.g. due to the flight missing night curfew regulations)
- Emergency or abnormal situation at the destination (e.g. due to runway closure due to an aircraft accident)
- Emergency or abnormal situation on board (e.g. due to insufficient fuel, system failure or medical issues)
Alternate Aerodrome
An alternate aerodrome is an aerodrome to which an aircraft may proceed when it becomes either impossible or inadvisable to proceed to or to land at the aerodrome of intended landing, where the necessary services and facilities are available, where aircraft performance requirements can be met and which is operational at the expected time of use.
Alternate aerodromes can be divided into three groups:
- Take-off alternate: Is an aerodrome at which an aircraft would be able to land should this become necessary shortly after take-off, and it is not possible to use the aerodrome of departure.
- En-route alternate: Is an aerodrome at which an aircraft would be able to land in the event that a diversion becomes necessary while en route.
- Destination alternate: Is an aerodrome at which an aircraft would be able to land should it become either impossible or inadvisable to land at the aerodrome of intended landing.
Almost all flights require Destination Alternates, but Take-off and En-route alternates are only necessary in specific circumstances, and the departure aerodrome may also be an en-route or destination alternate for the same flight.