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Airways New Zealand to trial 'Optimum Arrivals' into Auckland

Infonews Editor

Friday 20 April 2007, 3:29PM

By Infonews Editor

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Airways New Zealand, New Zealand's air navigation services provider, is to undertake a trial of a new type of approach procedure for Air New Zealand and Qantas international jet aircraft arriving at Auckland International Airport. Commencing mid-April, flights will be spaced to effectively allow them a 'glide descent' into the airport, from their top of descent point. These 'glide descent' profiles will be flown with the aircraft engines set at idle, thereby significantly reducing fuel burn and emissions.

Airways New Zealand says the purpose of the trial is to establish what the actual fuel burn is for an arriving flight where there is no requirement for any ATC intervention, and to gauge the potential fuel savings and associated emission reductions.

Lew Jenkins, Airways New Zealand's Main Trunk Manager, says Airways, Air New Zealand and Qantas have been working in close partnership to put the trial together.

"This is a perfectly safe procedure, and other flights will be controlled by Airways New Zealand's air traffic controllers to remain clear of the trial flight paths."

"All commercial airlines want to be safe but they also need to be profitable, fuel efficient, and environmentally friendly, and a key component in this equation is fuel. The airlines have plenty of detail on how their aircraft need to fly in order to burn the minimum amount of fuel, especially on the arrival segment, but traditionally this has been balanced by an air traffic control imperative driven primarily by on-time performance and runway capacity."

Jenkins says that this has meant that the way an aircraft needs to fly in order to use minimum fuel, particularly in the descent phase, is commonly at odds with the drivers for on time performance and runway utilisation.

"With the Optimum Arrival Trial, Airways will be looking in detail at what constitutes an 'optimum' arrival, ie, how much emphasis can be placed on chasing best fuel burn. From the trial we will be able to accurately gauge the impact this has on on-time performance and runway capacity and how accurately flights can arrive at an allocated time to provide spacing from other aircraft."

"We have chosen Auckland as the location for this trial because Auckland has a higher percentage of jet traffic than other airports, and they have a much higher percentage of international to domestic traffic than other locations."

Jenkins says the trial needs to happen in real time and in real conditions because simulators are not able to provide data to the level of accuracy that Airways requires to effect the trial.

"The subtle vagaries of the weather in particular, are only able to be produced in a simulator in crude blocks. We have also chosen only a very small group of aircraft to participate in the trial. These will be the Air New Zealand and Qantas 747 aircraft arriving into Auckland, which typically arrive at times of the day when other traffic is light. Therefore, there will be minimum disruption to other aircraft."

Airways New Zealand says the aircraft involved in the trial will be given a priority similar to a medical flight.

"They will fly the full arrival procedure at pre-agreed speeds and descent profiles, and they will not be given any speed control or level restrictions by air traffic control on their arrival."

Similar trials have been undertaken in other parts of the world, namely into Melbourne, Australia.

"This trial was called a 'Tailored Arrivals Trial' - 'tailored' in this context meaning that the arrival trajectory was calculated to fit each particular flight on each particular day at each particular time. The Australians were attempting to look at the current environment, including other aircraft around, and provide the most fuel-efficient arrival solution for each aircraft," said Mr Jenkins.

"A similar trial called a 'Continuous Descent Arrival' Trial (CDA) was undertaken in the Netherlands last year, and is similar to the trial Airways will undertake in Auckland. That trial was restricted to aircraft arriving into Amsterdam from the two participating airlines between the hours of 1130 local time in the evening and 0600 in the morning - the intention being to restrict the trial to a time when traffic was light."

A third trial is being run in San Francisco right now. This trial is called a 'Tailored Arrivals Trial'. It is very similar to the Australian trial but is using a larger number of aircraft in the trial.

"It probably does not matter too much what the names of the various trials are called - at the end of the day all these trials are looking at similar aspects of balancing the complex dynamics of efficient fuel burn and reduced emissions with accurate, on-time-arrival and an efficient utilisation of the runway capacity at the destination. Indications are that the savings will be significant."

Jenkins says the trial will provide the airlines and Airways New Zealand with the data and information required to help better define future air navigation planning and investment, which will achieve better industry economics, environmental benefits and safety.