Ryanair is facing intensified industrial action in Spain as the SEPLA pilot union has announced strike dates for 19, 20, 22, 27 and 29 September.

Around 900 pilots will be invited to walk out in protest at the closures of Ryanair bases in Lanzarote, Tenerefe, Las Palmas and Girona, eliminating a total of 120 jobs.

The action would take place alongside strikes by Spanish unions USO and SITCPLA, which represent cabin crew. They have called for action across the country on 1, 2, 6, 8, 13, 15, 20, 22, 27 and 29 September.

SEPLA accuses Ryanair of seeking to establish a series of "low cost of a low cost" companies to drive down wages and standards. It cites the establishment of a base in Palma de Mallorca by Ryanair subsidiary Lauda and the creation of Buzz Air, a Polish subsidiary that is offering pilot jobs in the Canary Islands.

The union says Ryanair is continuing to hire pilots, and argues that this "would make these layoffs inadmissible". SEPLA also questions whether Ryanair has followed the correct procedures in dismissing employees.

SEPLA president Oscar Sanguino states that the union will continue to engage with Ryanair in an effort to avoid the strikes: "We will exhaust all the ways to avoid this, but we remember that we are only defending our jobs."

Ryanair is facing the threat of industrial action in several European countries by pilots and cabin crew who accuse the airline of providing poor employment conditions.

Responding to the strikes called by SEPLA, SITCPLA and USO, the budget carrier states: "As the closure of Ryanair's loss-making winter bases in the Canaries cannot, and will not, be reversed, these strikes are unnecessary and doomed to fail."

The base closures are "irreversible until such time as the Boeing Max delivery delays are resolved", adds the airline.

It notes that it will have 30 fewer Boeing 737s than planned this winter as a result of those delivery delays. "This aircraft shortage has forced [us] to close some loss making winter bases, and cut aircraft numbers at others," it says. "These difficult decisions have affected many Ryanair bases this winter, not just in Spain but across eight other countries."

Ryanair also argues that as "almost all" the traffic at the Canary Islands bases originates overseas it "can be better served by aircraft based in other EU countries" without such "high costs and inefficiency".

The airline – which expects to cancel six Spanish flights on 1 September and eight the following day – warns that the calling of strikes "just eight weeks before Brexit" amounts to "an act of great self-harm" by the unions.

This story has been updated to include Ryanair's reaction

Source: Cirium Dashboard