LONDON - Thousands of British Airways (BA) passengers were left stranded after a massive technology failure disrupted hundreds of flights worldwide over the weekend.
The airline on Saturday (May 27) cancelled all its flights from Heathrow, Europe's busiest airport, and Gatwick in south London, after a power supply problem disrupted its flight operations worldwide.
While many of BA's computer systems are running again, London's Heathrow Airport said on Monday that there were still some disruptions to the airline's flights departing from the airport.
Here are some key questions facing the carrier following the disruptions.
WHAT CAUSED THE DISRUPTION?
Alex Cruz, the chairman and chief executive of BA, said on Saturday the failure was caused by a power supply problem and that there was no evidence of it resulting from a cyber attack.
The airline has also said it could not provide any further details at this stage, although many of its computer systems are running again.
BA had also previously suffered from other IT glitches that led to severe delays for passengers in July and September last year and some US airlines had also been plagued by similar computer outages caused by hardware problems, the Telegraph news website reported. Last August, Delta Air Lines cancelled hundreds of flights and delayed many others after an outage hit its computer systems.
Analyst Damian Brewer, at RBC Capital Markets, told the Telegraph that early diagnosis of the blackout suggests there were "fundamental management and planning weakness" by the airline's owner, the International Airlines Group (IAG), to prepare it for such incidents.
"It seems highly questionable why similar incidents with major US carriers in the last year have failed to see IAG move to ensure its airlines had plans in place to mitigate this risk, already seen elsewhere, and also to have contingency plans in place," he said.
"At present, it appears that BA management have seemingly not taken account of IT risk precedent already seen and already known at other carriers."
COULD OUTSOURCING HAVE BEEN BEHIND THE PROBLEM?
Meanwhile, the airline's GMB union pointed to the carrier's decision last year to outsource its IT jobs to India as a reason for the breakdown.
Mick Rix, the union's national officer for aviation, said: "This could have all been avoided. BA in 2016 made hundreds of dedicated and loyal IT staff redundant and outsourced the work to India. BA have made substantial profits in for a number of years, and many viewed the company's actions as just plain greedy."
The airline, however, has rejected the claim, saying: "We would never compromise the integrity and security of our IT systems". "IT services are now provided globally by a range of suppliers and this is very common practice across all industries and the UK government," it said.
Aviation expert John Strickland at JLS Consulting told the BBC that the issue would be one the airline would have to review. "Surely a business should be able to make an outsourcing decision without any problems, if it is done in a quality-controlled way. But this issue is part of the analysis that will have to be done by BA," he said.
HOW HAVE PASSENGERS BEEN AFFECTED?
The outage was especially bad timing for the airline because it came on a busy weekend ahead of a public holiday on Monday. Many British children are also starting their school half-term break.
While BA has declined to specify figures for flights or customers affected, Houston-based plane-tracking service Flight Aware saysthe carrier scrapped a combined 418 flights at Heathrow and Gatwick and delayed another 568 flights on Saturday. Another 115 flights, or 13 per cent of BA's services were cancelled as of 3.30pm UK time on Sunday, while 311 services, or 35 per cent, were delayed.
In addition to the travel disruptions, the airline's call centres and website were also affected. Passengers were also unable to rebook flights or retrieve luggage from the planes and there were also reports of travellers stuck for hours on grounded aircraft before being let back into the airport terminals.
At the height of the disruption on Saturday, some travellers also resorted to sleeping on yoga mats , according to Welsh international table tennis player Chloe Thomas whose flight to Germany for the World Table Tennis Championship in Düsseldorf was cancelled at the last minute.
"It's chaos, people are running about all over the place trying to rebook," she told The Guardian. "There's no one to help, no leadership. There are lots of people everywhere. There's nowhere to sit, so people are just lying on the floor, sleeping on yoga mats."
WHAT IS BEING DONE FOR PASSENGERS?
BA has said it is continuing to make "good progress" in its recovery. In a statement on Twitter on Monday, it said it would run a full schedule at London's Gatwick, adding that it intends to operate a full long-haul schedule from Heathrow along with a "high proportion" of short-haul service.
A BA spokesman said: "We apologise again to customers for the frustration and inconvenience they are experiencing and thank them for their continued patience."
The airline says that customers whose flights have been cancelled can claim a full refund or rebook to a future date for travel up until the end of November 2017, the BBC reported. They must also keep any food, transport or accommodation receipts in order to be able to make their claims.
The airline added: "We are refunding or rebooking customers who suffered cancellations on to new services as quickly as possible and have also introduced more flexible rebooking policies for anyone due to travel on Sunday and Monday who no longer wishes to fly to/from Heathrow or Gatwick. We have provided customers with hotel accommodation."
London's Heathrow said it had mobilised "additional Heathrow colleagues to assist passengers at the terminals and give out free water and snacks".
SOURCES: AFP, BLOOMBERG, REUTERS, THE GUARDIAN, THE TELEGRAPH, BBC