Take-off vs landing: which is louder?

People who live beside a runway and people who live 10 km out under the approach tend to give opposite answers to this question, and both are right. What you hear depends on how high a plane is when it passes you and how hard its engines are working, and those two things change in opposite directions for take-offs and landings.

The short answer: it depends where you live

Two of our sample reports show the two ends of this. In Winthrop, 0.8 miles (1.3 km) from Boston Logan, the loud days are the ones with northerly winds, with 130 loud take-offs a day. At Kew Green, 10 km from Heathrow, the loud days are the westerly ones, with 92 loud landings a day. On easterly days Heathrow's planes take off towards the east instead, but by 8 km out they are above 3,000 ft and fanning out onto their routes, and Kew Green counts 4 loud flights a day.

"Loud" here means above 65 dB outdoors, loud enough to interrupt a conversation.

Why take-offs are louder close to the airport

A plane taking off uses full or close to full power, and at that setting the engines are the loudest part of it. The noise spreads sideways as well as down, so homes beside the runway hear the take-off run and the start of the climb even though no plane passes over them.

Weight makes it worse. The Department for Transport notes that a heavily loaded plane is generally lower over the ground after take-off than a lighter one, so the same type passes lower, and louder, on a long-haul flight full of fuel than on a short hop.

Take-off noise near the airport is also what the rules target. At Heathrow the government sets noise limits for departing planes, checked at monitors about 6.5 km from where the take-off run starts: 94 dB(A) by day, 89 dB(A) in the late evening and early morning, and 87 dB(A) between 23:30 and 06:00, each for the loudest moment of the flight. Airlines that exceed them are fined. The limits apply to take-offs only; there is no equivalent for landings.

Why landings reach further out

Landing planes descend on a fixed 3° slope. That is shallow: about 170 ft of height for every kilometre from the runway. At Heathrow we measure landing planes at around 400 ft 2 km out, 1,400 ft at 8 km, and 1,800 ft at 10 km, over Kew and North Sheen. Take-offs are far higher at the same distance: 3,400 to 3,750 ft 8 km past the end of the runway. Our guide to how high planes fly when landing and taking off has the full figures.

Three more things make landings the bigger nuisance further out:

• They all use one line. By day at Heathrow, landing planes must join the final straight line no lower than 2,500 ft, about 8 nautical miles (15 km) from the runway. Take-offs turn onto a few set routes within a few kilometres, so their noise is shared between several areas: easterly take-offs from Heathrow split three ways, westerly ones two ways.
• The engines are not the only source. On approach the engines run at low power, but the lowered wheels and flaps make a noise of their own as the air rushes past them. NASA researchers have found that this airframe noise can be louder than the engines during the approach, which is why quieter engines do less for landings than for take-offs.
• A landing can be heard over a bigger area. When the Department for Transport modelled an Airbus A320neo at Stansted, a single landing was above 60 dB over 56 to 90 km², depending on the direction, against about 49 km² for a single take-off.

What the certification tests show

Every airliner type is noise-tested before it enters service, under international rules, at three points around the runway:

The results are in EPNdB, a certification unit that also accounts for how long the sound lasts and for any whine in it, so the figures are not what a sound meter in your garden would show. They do compare take-offs and landings on equal terms. For the heaviest version of each type, rounded, EASA's database gives:

The approach figure is the highest for every type, because the approach test point sits directly under a plane just 394 ft up. That matches experience: under the last couple of kilometres of an approach, landings are very loud too. The flyover figure, taken further out under the climb, is the lowest of the three for the twin-engined types, and above the lateral figure for the four-engined A380 and 747-400. The lateral figure is the one for homes beside the runway, where only take-offs pass at full power.

The type of plane matters as much: on approach, the 747-400 is 10 EPNdB louder than the A320neo. Our guide to the loudest and quietest passenger planes compares more types.

Night and early morning

The balance also changes with the time of day. At Heathrow no departures are scheduled between 23:00 and 06:00, but early arrivals may land from 04:30, and Heathrow says about 80% of its night flights land between 04:30 and 06:00. So under the approach, the planes that wake you are landings, while under the climb the day starts later. Night rules differ from airport to airport; our Heathrow page has its hours in full.

How to tell which one you will hear

Work out where you are in relation to the runways:

• On or near the extended centre line of a runway: you are under the approach in one wind direction and, close to the airport, under the climb in the other. Landings are the ones that stay low far out; take-offs are the louder ones close in.
• Beside the airport: take-offs, at full power, will be the ones you notice.
• Off to one side, further out: it depends on the departure routes, which the airport publishes, and on how often each runway direction is used.

Then watch real days. Our free flight map for Heathrow replays a whole day of landings and take-offs, so you can see which ones pass over a street and how high they are.