Ryanair pilots have denounced as “insane” attempts to pressurise them into flying with less fuel by imposing a cap on their safety reserves.

The low-cost airline is saving money by curbing the discretionary rights of pilots to request extra fuel.

The disclosure, made in internal company documents seen by The Sunday Times, has led to claims that the safety of passengers is being compromised as the price of oil soars.

Details of Ryanair’s policies emerged as the Civil Aviation Authority revealed that the number of emergencies declared in British airspace because of fuel shortages had doubled in five years. Last year, 27 planes were given the right to make priority landings, up from 11 in 2003.

There were also 18 “May-days” caused by fuel shortages in the same period, when British airports had to go on an emergency footing with fire engines on the runway.

Under European rules, every plane must carry a “contingency” load of about 5% of a trip’s fuel, and enough to divert to an alternative airport. Across the airline industry, captains also have a duty to anticipate delays from headwinds, storms and rerouting, and to request extra fuel to cope with this.

Pilots at Ryanair, Europe’s largest low-cost airline, must now abide by a limit of 300kg of extra fuel, costing £180. This provides about five minutes of extra stacking time for a Boeing 737.

Evan Cullen, a pilot with 19 years’ experience and president of the Irish Air Line Pilots’ Association, said commercial pressure on pilots to pare down the fuel they carry was compromising safety.

The internal Ryanair memo, sent to pilots in May, reveals that the company insisted that any request by a captain for extra fuel should be the “exception”. It referred to the 300kg maximum.

The memo shows that Ryanair is issuing warning letters to pilots who request extra fuel without explanation. Pilots claim such letters can be used in disciplinary proceedings.

The pilots have responded by complaining in anonymous postings on the Ryanair European Pilots’ Association website.

One says: “It is insane to push pilots to fly with the minimum fuel and take the risk of ending with a low fuel situation and maybe no place to go because the only diversion airport within reach will be mobbed by other aeroplanes.”

Pilots say Ryanair ranks them according to how much extra fuel they use. A spokesman for the airline rejected the pilots’ claims as “anonymous, unverified and inaccurate”. He said: “No pilot is allowed to fly with minimum fuel as these clowns claim.”

He admitted, however, that pilots were allowed extra fuel only in “exceptional cases”. He said Ryanair had suffered one Mayday in the past three years caused by fuel shortages.

A spokesman for the CAA said it would not comment because Ryanair’s fuel policy was monitored by the Irish Aviation Authority (IAA).

Additional reporting: Paul Eddy

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