Oxford Aviation Services v Civil Aviation Authority: judicial review of RAF Northolt civil flight safety dismissed

The High Court has dismissed a judicial review claim brought by the operators of three private airports — Oxford, Biggin Hill and Farnborough — against the Civil Aviation Authority's decision not to impose conditions on, or withdraw, the notification of RAF Northolt ("RAFN") for civil aircraft use. In a judgement handed down on 6 May 2026, Mr Justice Mould refused relief on all substantive grounds, granting permission on three of four grounds but finding none made out on the merits.

Background

RAFN has been notified under article 211 of the Air Navigation Order 2016 as available for civil aircraft operations — without conditions — since 2002. The claimants, whose airports service the same private business jet market as RAFN, contended that the CAA had subjected RAFN to a materially less rigorous safety regime than that applied to licensed civil aerodromes, creating an unlawful and commercially inequitable disparity.

Following a detailed letter of concern sent in January 2024, the CAA undertook a six-month investigation — including a safety assurance visit, liaison with the Military Aviation Authority ("MAA") through the Government Aerodrome Co-ordination Group ("GACG"), and a technical desktop review — before concluding that no regulatory action was warranted beyond a series of corrective observations issued to RAFN.

The grounds of challenge

Irrationality (Ground 1). The claimants argued the CAA had failed to conduct a rational safety assessment by omitting a gap analysis measuring RAFN's obstacle environment against the standards in CAP 168 and PANS-OPS. Mould J rejected this, applying the wide margin of appreciation afforded to expert regulatory bodies in technical and scientific matters set out in R (Mott) v Environment Agency [2016]. Crucially, CAP 168 does not apply to government aerodromes as a matter of law. Relying on the principles endorsed in R (Oxford Aviation) v Secretary of State for Defence [2015] EWHC 24 (Admin) — the earlier High Court judgement arising from the same aerodrome — the court confirmed that the CAA was entitled to rely on MAA assessments, the published Defence Aerodrome Manual and Aerodrome Operating Hazard Log, and its own specialist personnel, without being obliged to conduct a parallel gap analysis against civil licensing standards.

Reasons (Ground 2). Permission was refused. The judgement holds that the Decision — running to 76 paragraphs addressing each of the six grouped topics the CAA had identified — met the standard of propriety, adequacy and intelligibility established in Re Poyser and Mills' Arbitration [1964] and South Bucks DC v Porter (No 2) [2004].

Unlawful delegation (Ground 3). The claimants contended that paragraph 18(a)(ii) of the CAA–MAA Memorandum of Understanding effectively delegated the article 211 notification decision to the GACG — a joint body incapable of acting without MAA agreement. Mould J disagreed, reading the Agreement as a whole. Its express purpose is to facilitate the CAA's discharge of its own statutory functions; provisions confirming the CAA's sole decision-making authority under article 211 pervade the document. The GACG's role is collaborative, not determinative.

PANS-OPS interpretation (Ground 1A). A technical dispute arose over whether the 15-metre disregard threshold in paragraph 5.4.6.4 of PANS-OPS Volume II applies indirectly to the Obstacle Clearance Surface assessment under paragraph 5.4.6.6.1. Mould J declined to resolve it, applying the "tenability" principle from R (Corner House Research) v Director of the Serious Fraud Office [2009] AC 756. Since PANS-OPS is promulgated under the auspices of the Chicago Convention and the appropriate forum for resolving interpretive disputes is the ICAO's Instrument Flight Procedures Panel, a domestic court should not intervene unless the public authority's interpretation is untenable. The CAA's reading, endorsed by its specialist inspector, passed that threshold. The issue is to be referred to the IFPP.

Significance

The judgement consolidates the framework established in 2015 for the regulation of civil aviation at government aerodromes. It confirms that the CAA's safety obligations under article 211 can lawfully be discharged through collaborative oversight with the MAA, reliance on published military aeronautical data, and corrective observations — without replicating the full CAP 168 licensing regime. The tenability approach applied to the PANS-OPS question may also prove instructive in future cases involving unincorporated ICAO technical guidance.