A Helios Airways 737-800 was grounded by Cypriot aviation authorities last week after twice turning back with mechanical problems.

Safety concerns were first raised on Friday when a Heathrow flight returned to Larnaca; a cockpit warning light had shown a failure in a valve supplying air to the engines. The aircraft was passed as fit to fly over the weekend, but was forced to turn back a few minutes into Sunday’s flight to Glasgow with the same problem.

Helios said the malfunction did not endanger the flights, but passengers, who experienced breathing difficulties, reported freezing temperatures and water leaking from the cabin ceiling. Tony Bernie, a tour operator from Ireland, described the flight as “a terrifying experience.”

The stricken aircraft finally took off on Monday, after the faulty valve had been replaced, but 39 passengers refused to get on board. They were later flown home by Cyprus Airways.

The incident follows the August 15 tragedy in which Helios Airways flight 522 crashed into a mountainside in Greece. The 737-800 had twice been passed as fit to fly before taking off, but air-crash investigators have since concluded that the maintenance crew that signed the plane off left a pressurisation controller out of place.

Facilities at Larnaca have been described as “disgraceful” and “like a Third World country” by passengers, as the airport struggles with staff shortages and low morale. Both Larnaca and Paphos airports are to be sold to the private sector, and many employees face redundancy.