The storm brewing around budget airline Ryanair continued on Tuesday, with the airline's chief executive branding a pilots' group which raised concerns a "joke".
The airline's share price rose by around 2 percent in trading Tuesday morning, after falling by 4.5 percent on Monday.
On Monday night, British broadcaster Channel 4 showed a program which alleged that pilots for Ryanair had "deep-rooted" concerns over the safety of the airline. The program, called Ryanair: Secrets from the Cockpit - Channel 4 Dispatches, raised serious concerns that the airline's employment practices could have an impact on passenger safety.
The program used a survey conducted by the Ryanair Pilot Group which claimed that 94 percent of more than 1,000 Ryanair pilots and first officers surveyed wanted regulators to conduct an inquiry into how working practices could affect safety at the airline.
Read more: Ryanair pilots raise safety concerns
Evert Van Zwol, chairman of the Ryanair Pilot Group, told CNBC: "We don't want this to end here. The problem in Ryanair is that people are very reluctant to come forward with genuine complaints about the safety within Ryanair.
"There is no reason to believe that these pilots are any less professional than any others in any other airline in Europe. However, there is a culture within Ryanair which could be one of the factors leading to this situation. We are calling upon the regulator to take this very seriously."
The Ryanair Pilot Group is central to the controversy, withRyanair claiming that it is in fact a "PR front for the European Cockpit Association," a trade body. Ryanair has always resisted the formation of unions.
Michael O'Leary, chief executive of Ryanair, described the group as a "joke" and pointed out that Van Zwol, currently a KLM pilot, had never flown for Ryanair.
"This is clearly an example of the European pilots unions desperately trying to unionize Ryanair,failing and playing the safety card," he added.
He pointed out that pilots could express any concerns confidentially within Ryanair or to the Irish Aviation Authority (IAA).
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The budget airline is planning to issue a defamation action against the broadcaster. In the light of the program, the Ryanair Pilot Group called for an inquiry into how practices like zero hour contracts, where pilots are only allowed to work for Ryanair but are not guaranteed a certain number of hours, might impact safety.
The IAA was quick to reassure passengers that Ryanair is safe to fly, and issued a statement stating the airline's safety is in line with "all European Aviation Safety Requirements."
Concerns were raised last July at the airline after three Ryanair aircraft were forced to make emergency landings in Spain over fears they did not have sufficient fuel.
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O'Leary argued that the planes in each of these cases had enough fuel but the pilots were being cautious.
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