Definition of Diversion
A diversion occurs when a flight is required to land at an airport other than its original destination due to circumstances outside the control of the pilot or airline, such as severe weather. According to the US FAA JO 7110.65, diversions can be categorized into three main types:
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Air Turnbacks: The aircraft returns to the departure airport.
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En-route Diversions: The flight diverts to an alternate airport before reaching the planned destination.
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Destination Diversions: The aircraft changes course after arriving near the intended airport.
Reasons for Diversions
Several factors can lead to a diversion:
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Adverse Weather: This includes thunderstorms, heavy rain, or flooded runways.
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Aerodrome Issues: Maintenance work or operational hours can prevent landings.
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Emergencies: Security threats, accidents, or medical emergencies may also necessitate a diversion.
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Aircraft Issues: Problems like system failures, fuel shortages, or unruly passengers can lead to rerouting.
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Clearance Issues: Sometimes, air traffic control may not permit landing, or en-route airspace restrictions can affect the flight path.
In most cases, the pilot in command decides on the new destination, which is usually one of the alternates listed in the flight plan. However, if all planned alternatives are unsuitable, other options may be considered. Before making a final decision, pilots often seek additional information from air traffic services (ATS) or their airline’s operations team, who can provide critical insights on weather conditions and airport accessibility.
Real-World Examples
Air Turnback – E75L, Dublin, Ireland, 2022
On October 19, 2022, an Embraer E175-200 had to return to Dublin shortly after takeoff when the First Officer became incapacitated. The Captain took over and declared a MAYDAY. Fortunately, the aircraft landed safely despite experiencing a bird strike on approach.
En-route Diversion – CRJ9, North of Los Angeles, 2021
On November 29, 2021, a Bombardier CRJ900 experienced a fuel imbalance shortly after takeoff from San Diego. After confirming the issue, the crew declared a MAYDAY and diverted to Los Angeles. The problem was traced back to a pre-flight error in fuel management.
Destination Diversion – AT72, East Midlands, UK, 2023
On January 17, 2023, an ATR 72-200 faced an electrical malfunction during its approach to East Midlands. The pilot declared a MAYDAY and successfully diverted to Birmingham, where the cause was found to be a wiring defect from prior maintenance.
These examples illustrate how diversions can occur due to various challenges, emphasizing the importance of pilots making informed decisions under pressure.
