If Gatwick is given a new runway, it is inevitable that Go-Arounds (and holding) will increase, with 101,000 extra flights a year.
Go-Arounds 
happen for a number of reasons. They will not be helped by a new runway, if Gatwick Airport is successful when the Secretary of State for Transport makes her decision in October.
Many go-arounds are caused by the slow movement of the previous plane on the runway. If a new runway is built just for short haul departures, then with all arrivals having to land on the main runway, there could be more holding of arrivals to accommodate all the long-haul (and some short haul) departures from the main runway.
Missed approaches are often due to: pilots not knowing Gatwick (this could increase as the airport seeks to attract new airlines with a new runway); too fast an approach due to lack of ‘time to go’ to touch down given by air traffic control; and occupied runway due to ground congestion, lack of knowledge of the airport, and lack of piers/ terminal space to park an aircraft.
With new airlines, you get new pilots who do not often fly into Gatwick. Even established airlines lease planes and crew, so they may not know where to go after landing, causing knock-on delays. With the complex traffic-light system and the crossing of the potential new runway to reach the terminals, this could slow ground movements, leading to more delays and holding.
Congested airspace also does not help and can cause go-arounds, as Gatwick sits under Heathrow flight paths, as well as flights destined for other airports. More planes flying into and out of Gatwick, especially during the peak times of other airports, all adds to congestion and delays. Delays cause more holding, more CO2 (using more fuel), and are not liked by airlines. Air traffic control will endeavour to get planes on the ground as quickly as possible, but this can also lead to go-arounds – missed approaches.
Gatwick already suffers with lack of ground staff as well as terminals, to accommodate the existing number of flights arriving and departing. A new runway alongside the main runway will inevitably make this situation worse, with the shortage of seasonal staff in the area. This could well lead to an influx of minimum-wage staff, but an important factor to consider is that ground crew need training and security clearance, so a big question-mark hangs over how Gatwick will resolve this.
Bad weather can also cause go-arounds and, with the impacts of global warming, it is forecast that extreme weather patterns will occur more frequently.
Training and testing of aircraft are often seen by residents as go-arounds, as they take off and land immediately, flying a circuit at very low heights.
Go-Around details:
https://aircraftnoise.gatwickairport.com/2021/03/29/go-arounds/
Flight performance report for the first quarter of 2025:
https://www.gatwickairport.com/on/demandware.static/-/Sites-Gatwick-Library/default/dw4186d301/images/Corporate-PDFs/Noise-Reports/AO-Quarterly/Q1%202025%20AO%20Report%20V2.pdf
www.cagne.org
June 2025