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Divergent Missed Approach Protection System (DMAPS)

The Divergent Missed Approach Protection System (DMAPS) is a set of air traffic management procedures designed to make flights safer and more efficient for air travellers.

The DMAPS procedures safely manage an approaching aircraft that is unable to land for any reason, by reducing complexity and uncertainty, in line with the global move towards safety-by-design instrument flight procedures. They also reduce delays, as well as fuel burn and the associated CO2 emissions.

DMAPS was introduced at Wellington Airport on 1 December 2022 and has been in place at Christchurch Airport since 2020.

Wellington Airport

How have flight paths changed at Wellington Airport?

The new DMAPS procedures safely manage an approaching aircraft that is unable to land for any reason, including low cloud, fog or wind shear, and so flies what is known as a missed approach procedure. The new system has, in turn, required adjustments to the flight paths for jet aircraft departing to the north over the northern suburbs and to the south over Cook Strait.

Previously, the pilot of an aircraft that had missed its approach would have either followed the same instrument flight path as that used by jet aircraft departing to the north, or flown a circuit manually over Wellington Harbour using visual cues, before landing at Wellington Airport or diverting to another.

Under the new DMAPS system, jet aircraft departing to the north and aircraft that have missed their approach no longer fly the same path – they are now on separate flight paths that diverge 30 degrees from one another. Departing jet aircraft now climb on a flight path that turns slightly to the west of the former path, while aircraft that have missed their approach now turn slightly to the east of the former path.

What are the benefits of the new flight path system at Wellington Airport?

The DMAPS procedures are what is known as a safety-by-design system. They increase safety and efficiency by reducing complexity and uncertainty.

Pilots can now fly a more consistent and predictable missed approach flight path that is clear of departing jet aircraft. They can use instrument flight procedures, rather than relying on flying manually using visual cues to avoid terrain and uncontrolled airspace.

This reduces potential risks and is in line with the global aviation industry’s move towards instrument flight procedures that build greater safety into the design of aviation systems.

Initial data for January to March 2023 shows DMAPS procedures are reducing delays for flights to and from Wellington Airport by an estimated 41% compared to the same period in 2021 and 2022, and are projected to reduce aircraft CO2 emissions by 847 tonnes per annum, or the equivalent of 439 fewer cars on the road.[1] The delay reduction was achieved despite higher traffic levels and more than twice the number of poor weather days as in the same period in 2021 and 2022.

In February 2023, delays were the lowest ever recorded since measurements in this format began in 2008, excluding the February 2021 COVID-19 pandemic period. 

The DMAPS procedures reduce delays because they allow air traffic controllers to safely reduce the size of the gaps they require between approaching aircraft, particularly in poor weather. In the past, they would have held aircraft on the ground or in the air, or slowed them down enroute, especially during peak traffic periods.

The new procedures reduce fuel burn and the associated CO2 emissions, because they reduce both delays for all aircraft, and the overall number of kilometres flown by departing jet aircraft.

What does DMAPS mean for residents?

The new DMAPS procedures mean that residents in some areas may notice more departing flights, while those in other areas may notice fewer departing flights.

They do not mean departing or approaching aircraft are flying at lower altitudes over the northern suburbs. There have been no changes to any approach flight paths to Wellington Airport due to the introduction of DMAPS procedures – these have not changed since 2018.

Some residents in some parts of the northern suburbs have reported concerns about aircraft noise following the changes, while less noise has been observed elsewhere.

Airways is New Zealand’s air navigation services provider. We provide air traffic control services and design safe and efficient flight procedures.

Wellington Airport is monitoring the noise impact. It commissioned a noise study before and after the introduction of DMAPS procedures which found that while the change would be noticeable to some residents in parts of the northern suburbs, it would be only a slight increase and within reasonable limits.

Airways and Wellington Airport have met with community representatives, and we’ve heard from local people at a community meeting. In response, extra noise monitors are being installed in the northern suburbs, at locations nominated by community representatives in Khandallah, Johnsonville, Broadmeadows and Ngaio. Wellington Airport will share the results with the community.


[1] Calculation based on current New Zealand car and SUV emissions average of 161 grams of CO2/km. Refer – The Clean Car Import Standard.