UK air navigation service NATS has rejected budget carrier Ryanair’s claims that air traffic control operations favour London’s Heathrow and Gatwick airports, to the detriment of Stansted.

Ryanair has lodged a complaint to the European Commission and UK Civil Aviation Authority, based on delay figures in the first quarter of this year, which indicated that Stansted suffered far greater disruption than either of the larger hubs.

But NATS says these figures “coincide” with the introduction of new technology which affected the number of arrivals and departures at Stansted during that period.

London Luton airport, which also recorded large delay figures, was similarly disrupted, adds NATS: “Other airports were affected at other times over a six-month period.”

The air navigation service states that all carriers received advance notification of the timetable for the technology change, which is intended to increase capacity.

NATS dismisses Ryanair’s accusation that Heathrow was favoured over Stansted, insisting that it “does not discriminate” between airlines or airports.

“Ryanair performance this summer cannot be blamed on UK air traffic control,” it adds.

While the budget airline has claimed that NATS is not rostering sufficient air traffic control staff, NATS states that controller numbers are irrelevant because the airspace itself is capacity-limited.

“Additional aircraft cannot fly in that area safely without redesigning the airspace, which requires consultation with those affected on the ground,” it says. Raising controller numbers “will not make a difference”, it adds.

Ryanair's complaint comes a year after a formal CAA investigation cleared NATS of breaching licence conditions, after Ryanair and Stansted airport’s operator accused NATS of discriminating against Stansted flights and failing to provide adequate resources to manage traffic.

The airline's latest complaint states that London Heathrow is “being given special treatment”, citing CAA data for the first quarter of this year indicating that Stansted suffered 15,268min of air traffic control delays.

This figure included 13,420min attributed to air traffic control capacity but just 31min linked to staffing.

Ryanair points out that the Stansted total accounts for 52% of the overall 29,289min of delays recorded across the five main London airports during the first quarter.

The CAA data does not show any delays for Heathrow.

London Luton registered 8,814min of delays – some 30% of the total, and primarily due to capacity – while London Gatwick had 2,925min, the equivalent of 10%, all associated with staffing.

Ryanair has stressed that British Airways and EasyJet, large operators at Heathrow and Gatwick, are also shareholders in NATS – although it neglects to point out that EasyJet is also a major operator at Luton.

The Irish budget carrier’s chief operating officer, Peter Bellew, claims that NATS is not rostering sufficient air traffic control personnel, particularly during weekends, but that it is “hiding” this situation with “euphemisms” – using such terms as “capacity restrictions”.

“These disruptions are unfair and unacceptable,” he says, adding that Ryanair is demanding “urgent action” and putting forward a formal complaint regarding “blatant discrimination” to the European Commission and CAA.

The CAA says its position on the matter has not changed since its ruling last year.

While the CAA ultimately rejected Ryanair’s and Stansted’s previous complaint, its inquiry did find that the NATS’ En Route division had made “significant” cuts to operational staffing, and that resilience had been weakened by a combination of unplanned retirements, lack of overtime take-up, and sickness rates. There was no evidence, it added, of undue preference or discrimination.

Source: Cirium Dashboard