When aircraft have to land due to an issue that is not an emergency, they will often return to their point of origin. However, some late-night flights end up diverting elsewhere. Night curfews can cause this at airports.

Airports can be a touchy subject for local residents. While they are essential to allow people to travel the world quickly, many who live near the airport may get fed up with the noise of constant arrivals and departures. While this is harder to avoid during the day, some airports have curfews during the night to give residents some quiet hours to sleep.

How do curfews work?

There are several different types of curfews for airports. Some airports will have a blanket ban on flight operations between certain hours. This is the case in Frankfurt, where flights are generally banned between the hours of 23:00 and 05:00.

Some other airports have slightly different rules where aircraft below a certain noise threshold, such as Embraer’s super quiet E195-E2, are permitted to operate, but older noisier jets aren’t. In addition, some mix the two rules, with a blanket ban between certain hours and restrictions on either side.

Can any aircraft fly during a curfew?

There are several circumstances where aircraft operations can continue while a curfew is active. Firstly, any aircraft facing an emergency will typically be able to use the facility regardless of restrictions.

However, this isn't the case if the aircraft is returning out of caution for a maintenance issue. In 2019, a Lufthansa A340 flight that had departed from Frankfurt Airport decided to turn back over the Atlantic. As the aircraft would’ve landed after 23:00, it ended up touching down in Cologne, with the passengers taking busses for the two-hour drive back to the airline’s stronghold.

Other airports may have quotas in place for nighttime operations. This is the case at London Heathrow Airport. Heathrow is limited to 5,800 night operations between 23:30 and 06:00 each year. This averages out at around 15 per day. This allows flights with a genuine need to use the airport to land while discouraging frequently scheduled operations.

Tackling noise during the day

Of course, noise isn’t exclusive to nighttime operations, though it may be more noticeable with less other background noise. Some airports, such as Frankfurt, are well aware of this, undertaking several programs to reduce noise.

Frankfurt Airport charges aircraft based on the amount of noise they emit. They are placed in one of 16 categories depending on how much noise they generate. Such changes have prompted several airlines to switch to more noise-efficient aircraft at the airport. In 2015, LATAM would’ve paid a change of €869 for each A340-300 landing at Frankfurt. Meanwhile, its Boeing 787 only attracts a charge of €267.

The story was the same for Lufthansa. While its Boeing 747-400 attracted a charge of €2,173, the newer Boeing 747-8 was only changed €1,292. The Airbus A380 drew a bill of €1,298. Interestingly, Lufthansa has opted to bring the Boeing 747-400 back in the wake of COVID-19 but not the Airbus A380, despite the decrease in noise charges.

Between 2012 and 2015, The percentage of charges accounting for landing and takeoff noise increased by 120% at Frankfurt Airport. Higher costs are levied during night hours to try and encourage carriers to fly during the day.

What do you make of airport noise curfews? Let us know what you think and why in the comments!