A Hong Kong Airlines A350-900 cancelled its climb out of San Francisco airport on Monday (29/07/19). Pilots reported a malfunction of flight controls. The Airbus was slotted into a hold at 6,000 feet in order to burn off fuel, landing five hours later.
According to FlightAware, Hong Kong Airlines Flight HX-61 had taken off from SFO at 14:15 local time on Monday. The aircraft was cleared to climb to 19,000 feet but shortly after departure the crew encountered a “flap issue”.
The problem was deemed serious enough to warrant the return of the aircraft to San Francisco. Despite the absence of an emergency squawk, the pilots requested to remain at 3,000 feet while they performed a series of cockpit warning checklists. The local air traffic controller (ATC) directed them instead to 4,000 feet and asked that they make clear their intentions.
Following various cockpit assessments, the crew requested vectors to the airport due to the unresolved glitch. However, with the aircraft fully laden with fuel the pilots were forced to lessen the aircraft’s landing weight. Its burn route lasted four hours and fifty minutes.
Fuel dump and burn
It is not clear whether HX-61 was fitted with the A350’s optional fuel jettison system. In any case, the crew did not opt (or were not permitted) to dump fuel. Instead, the aircraft circled over the area in order to burn off enough fuel to make a safe and controlled landing.The plane touched down at SFO at 19:20 local time. The departure had already been delayed by over an hour. According to SFGATE, a spokesman for the airport said the flight was, “rescheduled for Tuesday and departed at 09:30 the next morning” bound for HKG.
When extended, aircraft flaps change the profile of the wing. Doing so generates dynamic lift, which is why flaps are selected by degree prior to take off.
Not deploying flaps can have disastrous consequences. In 2008 a Spanair McDonnell Douglas MD-82 crashed on take-off due to an improper flap selection. An interim report also blamed a faulty alarm system that would have notified the crew of the condition.
The extension of wing flaps also increases wing drag and slows an aircraft, which is why flaps are extended by degree as an aircraft approaches an airport.
There are only sketchy details of the case of HX-61. But the pilots’ decision to return to SFO following the fuel burn indicates a far from straightforward problem.
As we reported, Hong Kong Airlines will cease to fly from Hong Kong to San Francisco from October 4th this year. The route from Hong Kong International airport has been operated for a little under two years. Its closure comes amid a financial downturn and is thought to be part of a restructuring program to regain a degree of buoyancy.
Since its inaugural flight in 2006, the airline has sought to disrupt Cathay Pacific’s stranglehold on the US and Canadian markets. However, Hong Kong Airlines’ long-haul operations which took off in 2017 (Vancouver, Los Angeles, et al.) have proved costly.
Further US route closures will be telling.