Context is everything – court adopts purposive approach to runway end safety area criteria


Landing at Wellington Airport, at the bottom of the North Island of New Zealand, can be hair-raising. A combination of strong cross winds, a tricky approach through hills and a short runway with water at either end has seen Wellington Airport listed as one of the scariest airports at which to land.(1) A recent Supreme Court judgment considered a judicial review application about the length of runway end safety areas (RESAs) under a proposed runway extension.(2) Users of the airport might be reassured by the Supreme Court's finding that, under the existing statutory regime, more than a cost benefit analysis is required; among other matters, a mandatory consideration includes the need to improve aviation safety.


Wellington International Airport Ltd operates Wellington Airport, which has 90-metre RESAs at each end of the runway. Wellington International Airport wished to extend the runway and approached the director of civil aviation to ask whether RESAs of 90 metres would be acceptable to him in respect of the extended runway. The extension involved a high cost per square metre, so there was a strong incentive for Wellington International Airport to seek the shortest possible RESA. The director advised that a 90-metre RESA would be acceptable.

The New Zealand Air Line Pilots' Association Industrial Union of Workers Inc issued judicial review proceedings challenging the director's decision. The union has long advocated for RESAs of at least 240 metres. The judicial review application was unsuccessful in the High Court but succeeded on appeal to the Court of Appeal. Wellington International Airport and the director each sought and were granted leave to appeal to the Supreme Court.

Regulatory framework

New Zealand is a party to the Convention on International Civil Aviation (agreed in Chicago in December 1944). The convention requires that airports servicing particular categories of aircraft have RESAs at each end of the runway. These requirements were implemented in New Zealand through the Civil Aviation Rules, made under the Civil Aviation Act 1990.

The Supreme Court summarised the existing relevant requirements under the rules as follows:

"(a) First, a RESA must extend to a distance of at least 90 m and, "if practicable", to a distance of at least 240 m, from the end of the runway strip (or the greatest distance practicable between 90 and 240 m).
(b) Second, a RESA must be "acceptable" to the Director of Civil Aviation (the Director)."(3)

In considering the appeal – as well as reviewing the international and national regulatory framework in detail – the Supreme Court noted changes to the act made in 2004 to implement a national transport strategy. Before the amendments, one of the minister's two functions was "promoting safety in civil aviation at a reasonable cost", assessed by a national cost-benefit analysis. Following the 2004 amendments, the act's focus shifted. The wording "promoting safety in civil aviation at a reasonable cost" is no longer in any of the sections setting out the objectives and functions of the minister or director and is no longer a core principle of the act.

The court held that an important effect of the 2004 amendments was to place a greater emphasis on the promotion of aviation safety. Cost remains one of a number of considerations when actions are taken under the act, as it is one of 12 mandatory considerations for the minister in the rulemaking process. In interpreting the Civil Aviation Rules, in order to ascertain the nature of the decision that the director was required to make, the Supreme Court considered not only the wording of the rules themselves but also the considerations that the minister was required to take into account when the rules were made.


Director's decision

In making his decision, the director had focused on what Wellington International Airport had proposed – namely, a 90-metre RESA – and had refused to consider alternative options, such as arresting systems, on the basis that they had not been proposed by Wellington International Airport. The court held that the director had erred by starting with the Wellington International Airport proposal and not with the requirements of the Civil Aviation Rules. As the rules required a RESA of at least 240 metres if practicable, that should have been the director's starting point. If a RESA of that length was impracticable, the director had then to consider whether a length between 240 and 90 metres was practicable. A 90-metre RESA could only be acceptable if that was not the case.

The court considered the meaning of 'if practicable'. The union argued that 'practicable' meant feasible in a physical sense (the interpretation accepted by the Court of Appeal), while the director and Wellington International Airport argued that it meant reasonably practicable as assessed on a cost-benefit basis (the approach taken by the High Court). The Supreme Court held that the meaning in its context was more nuanced than either contention.

The Supreme Court held that assessment of what is practicable must consider:

  • the context of the relevant rules;
  • the statutory framework which produced them; and
  • the particular circumstances of the relevant airport, including the context in which the director's approval was sought.

The Supreme Court disagreed with the Court of Appeal's view that 'practicable', when dealing with the construction of an aerodrome runway, meant what was feasible or actually able to be constructed, with cost only becoming a factor at the extreme. On the other hand, while accepting that a cost benefit analysis may help the director to reach a determination about what RESA length was acceptable to him, the director had erred in law by basing his decision on a cost/benefit analysis alone.

The Supreme Court noted that, since the director's decision, Wellington International Airport's runway extension proposal had changed and the latest proposal would require further approval by the director. The court directed that the amended proposal should be considered in light of its decision.


This decision reflects the contextual and purposive approach commonly employed by New Zealand courts when interpreting statutes. The Supreme Court rejected the Court of Appeal's approach of focusing on the dictionary meaning of 'practicable' and instead considered the meaning in context, considering not only the rule in which the word appeared but also the statutory regime under which the rule was made and the international conventions and policy documents which the statute sought to reflect. It found that the director's approach might have been appropriate in the context of an earlier version of the act, but that his decision should have reflected amendments to the act which effected changes adopted by New Zealand, domestically and by way of its international obligations.

For further information on this topic please contact Kerryn Webster at Wilson Harle by telephone (+64 9 915 5700), fax (+64 9 915 5701) or email ([email protected]). The Wilson Harle website can be accessed at



(2) Wellington International Airport Ltd v NZ Air Line Pilots' Association Industrial Union of Workers Incorporated , [2017] NZSC 199.

(3) Footnotes omitted.