Have you ever been sound asleep on a hot summer night, windows open to allow some fresh air in, only to be rudely awakened by the loud noise of jet engines? Avoiding situations like this is only one of the reasons airports nighttime curfews exist.
Airport curfews mean that either no, or a limited number of flights are allowed to take off and land during certain time intervals, commonly between around 11 pm to 6 am. These are set up by local or state authorities and while in Europe they are the norm, the US generally lacks such regulation.
1. Why are curfews important?
Besides disturbing the quality of sleep of people living close to airports, noise pollution can have serious health impacts. On average, jet engines emit between 80 dB and 100 dB. For comparison, noise levels at a bar are around 75 dB to 80 dB, while the limit considered safe for humans is 85 dB, after which temporary or permanent hearing loss is likely to occur, depending on the time of exposure. Keep in mind that the decibel scale increases exponentially, thus an environment at 80 dB is in fact 10 times louder than one at 70 dB and 100 times louder than one at 60 dB.
Recent studies have also correlated living near airports with a higher risk of heart attack. Research led by Imperial College London analysing hospital admissions for cardiovascular diseases among residents whose homes are under Heathrow Airport’s flight paths found “evidence of a small increase in the risk” of being admitted to hospital among people who had experienced higher noise during the previous night.
Another study found that 220,000 local residents are “strongly inconvenienced” by the noise around Brussels Airport, 109,000 having their sleep seriously disturbed, 51,000 being exposed to an increased risk of hypertension and 2,000 being strongly at risk of developing ischemic heart disease (heart attack, angina pectoris, etc.). The study calculated that each night flight could have an impact of roughly €36,000 in health damage, according to Belga news agency.
From a different point of view, high levels of noise bring down the value of properties closer to airports, eventually deterring the development of residencies, missing an economic opportunity.
2. Impact on the industry
Both airports and airlines are at a loss when curfews are being implemented by authorities. Fewer flights means less revenue for both sides of the industry, however, airlines also have to pay for not respecting night intervals.
Curfews are not necessarily a complete ban and a limited number of flights, operated with low noise aircraft, are allowed at night. To bypass the restrictions, airlines acquire quitter planes. According to Simple Flying, the quietest double-aisled aircraft are the Airbus A380 and Boeing 787 Dreamliner, while for single aisle, the Boeing 737 MAX, Airbus A220 and Airbus A320neo take the lead. These are all relatively new, modern aircraft that airlines switch to not just for their quieter engines, but also for being more fuel efficient and generally more sustainable. Some airlines however cannot afford fleet renewal and are bound to strictly follow the curfews.
There are several outcomes for when airlines break these restrictions. Some flights, that are delayed for good reason and miss their intended take off or landing slots, could be allowed to break the curfew with no penalties. But this is not usually the case. In Brussels for example, where the city council has this year extended the night interval from 11 pm – 6 am to 10 pm – 7 am, the airport has recently announced that delayed flights, regardless of the reason, will no longer receive landing or take off slots, thus cutting the number of night flights by about 10%.
In most cases, airlines that do not respect night intervals are issues fines by local aviation regulators. These are usually high enough to determine airlines to simply cancel a flight instead of breaking the curfew. Repeat offenders at Sydney Airport are charged up to US$366,000 for example. On the other hand, according to a report from inewsource, San Diego’s penalties are so low that it registered 89 unauthorised flights during the night interval in 2022 and 337 violations over the past 6 years.
