Why are some flights delayed in bad weather and others not?

There are numerous conditions under which your flight may be delayed while a neighboring one departs or lands on time. And this isn’t just about weather—it can also depend on factors like the pilots.

Answered by the Director of the Airport Operations Control Center

Whether a flight is delayed or not depends on many factors. For example, three key conditions are considered: the aircraft’s equipment and the destination airport’s compliance with ICAO (International Civil Aviation Organization) standards; the crew’s training for operating flights in challenging weather conditions; and the weather at departure and arrival airports, as well as at alternate airfields.

According to ICAO standards, each airport has three categories of landing minimums, which define permissible visibility ranges. For instance, Chișinău, as an international-status airport, is considered “all-weather.” Its runways are equipped with radio beacons and lighting systems necessary for landing aircraft in low-visibility conditions.

Another critical factor for flight safety (especially in adverse weather) is the condition of the runway. Primarily, this is determined by the friction coefficient. Even if the runway has the required equipment, heavy snowfall means it must be cleared quickly, along with taxiways. Heathrow Airport has two independent runways and a modern fleet of airfield maintenance vehicles. In winter, during snowfalls, runways are cleaned in patrol mode without stopping. While a convoy of 10–12 snowplows clears one runway (taking up to 35 minutes in heavy snow), the other remains operational for arrivals and departures. The equipment then shifts to the second runway and back, allowing the airport to operate normally without flight delays. In recent years, Brussels Airport (Belgium) has never closed due to weather conditions.