Is this house under a flight path? 5 ways to find out

People talk about "the flight path" as if it were one line in the sky and a house were either under it or not. An airport has several paths, used on different days, and each is a corridor that is narrow in some places and kilometres wide in others. The question worth answering is how many planes pass close enough to be loud, and on how many days.

Why "under a flight path" is not a yes or no

Three things decide how much a house hears.

Whether it is under a landing or a take-off path. Landing planes fly the last 15 km or so along a straight line from the end of the runway, all in the same place and at the same height. Further out, air traffic control brings them onto that line from wide areas, so the planes are spread over many kilometres. Take-offs follow set routes at first and then fan out. At Heathrow each departure route is a corridor 3 km wide, 1.5 km either side of its centre line, until planes reach 4,000 ft; after that, controllers can turn them straight towards their destination. At Gatwick, departures stay on their route until 3,000 or 4,000 ft, depending on the route.

How far to the side it is. A plane does not have to pass directly overhead to feel overhead. In 2017 the Civil Aviation Authority proposed counting a plane as an overflight when it passes more than 48.5 degrees above the horizon and below 7,000 ft. At that angle a plane is about 3 dB quieter than it would be directly overhead at the same height, which is roughly the smallest difference most people notice. So the higher the planes, the wider the band that hears them: a plane 400 m to the side counts as overhead at 2,000 ft, but not at 1,000 ft, where it sits lower in the sky.

How often that path is used. Planes take off and land into the wind, so each approach, and each set of take-off routes, is only busy when the wind blows from the right side.

At Heathrow, planes landed towards the west on 62% of days over the last year and towards the east on 26%; on the rest, the direction changed during the day. Our Kew Green sample, 10 km east of the runways, shows what that split does to one street: 92 loud landings a day with westerly winds, and 4 loud flights a day with easterly winds.

The five checks below answer all three questions for one address. For the wider checks before buying, such as night flights and what to ask the seller, see how to check aircraft noise before buying a house.

1. Draw the runway lines on a map

Open a satellite map, find the runways, and extend each one in a straight line beyond both ends for about 20 km. Most map apps have a measuring tool for this.

• If the house is within a few hundred metres of a line, it is under an approach. Every plane landing in that direction passes over it, at much the same height each time.
• Work out that height. On a normal 3-degree approach, planes descend about 170 ft for every kilometre, so they are roughly 1,700 ft up 10 km from the runway. At Heathrow they pass Kew, 10 km out, at about 1,800 ft.
• Draw a line for every runway. Heathrow's two approaches from the east run about 1.4 km apart: one over Chiswick and Kew, the other over Putney and North Sheen.

This shows the landings and the first kilometre or two of take-offs. It does not show where take-offs turn, which is the next check.

2. Look up the airport's route maps and flight tracker

Airports publish maps of their departure routes, and some have tools that start from an address.

• Route maps show where take-offs are meant to fly and how wide each corridor is. At Heathrow, more than 95% of departures stay within the published routes. Arrivals usually have no fixed route until they join the final approach, so maps show them as broad areas.
• Address tools. Heathrow's Your Area portal takes an address or a spot on the map and shows typical flight paths on westerly and easterly days, with noise contours. Its xPlane tool lists the Heathrow flights that passed a location up to 60 km from the airport, with heights and aircraft types, going back five years; it gives no noise readings. Gatwick's portal works the same way for its neighbours.
• WebTrak runs at airports in Europe, Australia and North America, including Heathrow, Gatwick, the New York airports and Sydney. It replays past flights with their heights and, near the airport's noise monitors, the levels they measured. Live views run behind real time: by 3 minutes at the Australian airports, and by about 21 minutes at the New York airports.

These tools are the most exact record of where planes flew. Their limit is that you look at one day, or one date range, at a time, and most give counts or tracks rather than how loud each plane was at your address.

3. Check the official noise contour map

A noise contour map shades the area around an airport by average sound level. In Europe, a strategic noise map must be published every five years for every airport with more than 50,000 flights a year, and the next round is due in 2027. The UK draws its contours for an average summer day and treats 51 dB as the level at which adverse effects begin. In the US, the FAA treats 65 dB DNL as the threshold for significant exposure.

If the house is inside a contour, it is under a flight path. If it is outside, it may still be. Contours average the noise over the day and the year, so a street with dozens of loud landings on westerly days and almost none on easterly days can fall outside the lowest band. Our guide to official airport noise maps explains what they show and what they miss.

4. Replay real days and tap the street

Our free flight map replays a whole day of landings and take-offs at an airport in about a minute. Tap the street and it tells you how many loud planes it heard that day, loud meaning above 65 dB outdoors, enough to interrupt a conversation.

Replay at least three days: a typical day in each runway direction and the busiest night. If the count is close to zero every time, the house is not under a flight path in any sense that matters. If one direction brings dozens, you know which days will be loud, and the airport's split of directions tells you how many of them to expect.

5. Watch and listen on the right day

A visit confirms what the maps say, as long as the planes are coming over the house that day. Check which way the airport is operating before you go. Heathrow posts it live on X as @HeathrowRunways, and at Schiphol the air traffic control service shows the runways in use, updated every five minutes.

Then stand outside for 15 minutes at a busy time of day. Count the planes and note how high they are in the sky: if you have to tilt your head back more than about halfway between the horizon and straight up, the plane is overhead by the CAA's definition. Our guide to viewing a house near an airport covers the timing in detail.

What a real answer looks like

By the end of these checks, "is it under a flight path?" should have turned into a few numbers:

A Flight Noise report gives the last two for the exact spot you pin, from every recorded landing and take-off of the last twelve months, with the heights, the runway split and a real day of each kind replayed plane by plane.