Heathrow trials steeper approaches for landing aircraft in efforts to reduce noise on the ground
(photo: Heathrow Airport)
Wed 19 Aug 2015 – London’s Heathrow has started trialling steeper approaches for aircraft landing at the airport in efforts to reduce noise for residents on the ground. The international standard set by ICAO for most airports is a glide path of 3 degrees and the trial, which has been approved by the UK Civil Aviation Authority, will involve aircraft approaching at an angle of 3.2 degrees approximately 8 nautical miles (10 miles) from touchdown and will be used on all four runway approaches. The trial, which runs until 16 March 2016, will test whether approaches of up to 3.5 degrees at the airport are possible. Although optional, Heathrow is confident that a large number of airlines with the necessary onboard navigational equipment fitted to their aircraft will take part in the trial. Frankfurt Airport started a similar trial in October 2012, although the results are still being evaluated.
If adopted, Heathrow would become the only airport in the UK to introduce steeper approaches as a means to reduce noise on the ground. The preferred ILS (Instrument Landing System) glide path was increased from 2.5 degrees to 3 degrees by ICAO in 1978 but there are around 30 airports in Europe alone with glide path angles above 3 degrees in order to meet obstacle clearance requirements. One such airport is London City, where the approach angle is 5.5 degrees but is used by a different aircraft type mix than that experienced at major international airports such as Heathrow.
Heathrow says it expects aircraft will be 170 feet higher than usual at the 8nm point when the approach procedure comes into effect but accepts that evidence suggests only some residents may benefit from reduced noise. Mobile noise monitors have been deployed for the duration of the trial and the airport has pledged to summarise the findings afterwards in a report.
According to its 2013 sustainability report, Frankfurt’s airport operator Fraport says an initial evaluation on its steeper approach trial has shown the maximum level of noise produced has been reduced by 0.5 to 1.5 dB (A), depending on the measuring station and the type of aircraft. A Fraport spokesman said the trial is confined to the northwest runway and consultations with residents were ongoing as part of the evaluation.
Heathrow said it has already briefed a range of stakeholders about the trial, including the Heathrow Airport Consultative Committee and the Community Noise forum.
HACAN, which campaigns against Heathrow expansion, reports it receives more complaints about aircraft noise from London residents east of the 10-mile approach point for arrivals than it does from those living in areas closer to the airport. This, believes the group’s John Stewart, may be down to more of an acceptance of aircraft noise from those living around the airport, whereas those living further away experience less respite and may have moved into an area not expecting to be affected by a constant flow of low-flying air traffic.
“The number of planes flying over parts of Southeast London can be considerable, with HACAN having recorded over 40 planes an hour, the vast majority under 4,000 feet,” said Stewart.
“Heathrow has changed, and taken a new approach to addressing our impacts on communities, including when it comes to noise,” responded Matt Gorman, Heathrow’s Director of Sustainability and Environment. “Our ‘Blueprint for Noise Reduction’ has been driven by feedback from local communities and its role is to challenge the industry to think innovatively about ways to reduce noise. Steeper approaches are just one step in the right direction and, along with other quieter operating procedures and incentives to bring quieter aircraft into operation, will ensure fewer people are affected by noise, even with an expanded airport.”
Heathrow has asked airlines serving the airport to adhere to their scheduled daily night flight arrival times so that local communities can have predictable noise respite during sensitive hours. Since the start of its Fly Quiet programme, the number of airlines keeping to their schedule has remained static, reports the airport, but others continue to be in breach every quarter. Heathrow points out that this does not impact the overall number of flights operating in early morning hours as this is legally restricted by government, but its technical team is actively engaging with those poorly performing airlines.
Publishing its seventh quarterly Fly Quiet league (January to March 2015), Heathrow has commended Cathay Pacific, KLM, LOT and Finnair for their improved noise performance at the airport.