This proposal is for an Applicability and Policy Alignment Check.
GAL is in the process of reviewing and updating its Departure Noise Limits (DNL) scheme, which includes incorporation of a change in the minimum altitude to be achieved at the fixed monitoring point 6.5 km after start of aircraft roll from 1,000ft to 1,200ft.
Currently, departure noise is measured at 5 noise monitoring terminals (“NMTs”), located 6.5km from start of roll. The noise limits are subject to positional, equipment and tailwind adjustments. Aircraft are subject to a fine if they exceed the stipulated noise limits for the relevant time of day. The current limits have been reviewed in order to reflect modern fleet performance and new limits have been proposed.
During the course of the review, it was found out that a requirement related to altitude at 6.5km from start of roll, which is set at 1,000ft is no longer working well with the positional adjustments of the NMTs. Positional adjustments were originally calculated using the altitude requirement of 1,000ft. As modern aircraft tend to climb faster and fly higher over the monitors, the positional adjustments to the NMT noise readings need to be changed. Further analysis showed that aircraft typically meet at least 1,200ft altitude requirement at 6.5km from the start of roll, which is also the proposal for change.
The requirement is described in section AD 2.21 Noise Abatement Procedures in the AIP.
The key objective is to change the minimum required altitude at 6.5km from the start of roll in order to correct the noise monitor positional adjustments.
It was found out that a requirement related to altitude at 6.5km from start of roll, which is set at 1,000ft is no longer working well with the positional adjustments of the NMTs. Positional adjustments were originally calculated using the altitude requirement of 1,000ft. As modern aircraft tend to climb faster and fly higher over the monitors, the positional adjustments to the NMT noise readings need to be changed. Further analysis showed that aircraft typically meet at least 1,200ft altitude requirement at 6.5km from the start of roll, which is also the proposal for change.
The current minimum altitude at 6.5km from start of roll is 1,000ft.
The change is related to departures only. In 2022, there were 214,806 movements at London Gatwick airport.
Approximately 50% were departures.
This proposal only requires a minimum altitude change at 6.5km from the start of roll.
