Investigators have determined that an aileron cable fracture on a Corendon Dutch Airlines Boeing 737-800 resulted from insufficient lubrication.
The Dutch Safety Board says the inspection interval for the cable at the time of the 8 July 2022 incident was 4,000 cycles or 24 months.
It had been inspected 20 months beforehand. But the inquiry could not verify whether the cable had been consistently maintained and lubricated, and says that determining the degree of wear during inspections is “difficult” owing to their size and accessibility.
The safety board adds that it cannot tell whether the inadequate lubrication or the inspection interval had the greater influence on the incident.
But it points out that the inspection interval was extended last year to 6,600 cycles or 36 months.
The aircraft (PH-CDF) had departed Heraklion in Crete for Amsterdam when, just after take-off, the crew noticed the jet was rolling to the left – although it remained controllable, partly owing to favourable weather conditions.
Its pilots used rudder and aileron inputs to counter the roll and diverted to Athens. None of the 179 passengers and six crew members was injured.
Inspection of the jet, originally delivered to TUIfly Nordic in January 2000, found that the cable between the left aileron and the feel-and-centring unit had broken.
Greek accident investigators passed the investigation responsibility to the Dutch Safety Board.
The inquiry says it also assessed a 2019 cable break on another 737-800, but states that only three such events have been reported to Boeing since 1997.
Over the past three decades, hundreds of millions of flights have been carried out without safety incidents using aileron cables of the Boeing 737,” it adds. “The Dutch Safety Board therefore does not consider it necessary to issue a safety recommendation.”
