London - Thousands of British Airways passengers suffered delays of up to 24 hours on Thursday after the airline’s computer systems went into meltdown.
Dozens of planes were grounded in the chaos, said to have been triggered by a glitch in BA’s global flight planning systems.
It is the latest in a series of disastrous computer failures at the airline and it could now face another multi-million pound compensation bill.
The airline has also had to deal with the fallout from industrial action by pilots over the summer.
The latest fiasco began on Wednesday evening when pilots found they were unable to file flight plans, which inform air traffic controllers of intended courses.
The outage led to crippling delays while pilots manually plotted their course on old-fashioned charts before back-up systems kicked in.
In the worst case, two flights from Cancun, Mexico, and Kingston, Jamaica, arrived into Gatwick almost 24 hours late.
A flight from Pittsburgh was also delayed, landing at Heathrow more than 12 hours behind schedule. The delays meant a small number of outbound flights had to be cancelled, including a flight from Gatwick to Orlando.
Passengers complained of being left in the dark over the cause of the outage. Some said they weren’t informed of problems until after they had checked in.
On Thursday night BA refused to confirm the cause of the computer crash. However, a number of passengers were told it had been caused by a glitch in BA’s navigation systems.
One passenger on a flight from Los Angeles to London said: "The woman I spoke to said the flight-plan generator had crashed. It seemingly means pilots cannot get journey details and are left stranded. We should have taken off hours ago. It’s chaos."
Another passenger affected was Jess Gale, whose flight from Boston was delayed by over two hours. The 25-year-old, who travelled to London for a romantic getaway with her boyfriend, said: "I was supposed to leave at 9.30pm and it was delayed by over two hours.
"At the time they said that the plane coming in was delayed, but once we got on the plane the pilot said the whole British Airways system was down and they had to do all the paperwork manually. If I needed to get here on time I’d think twice about flying British Airways again."
The airline is facing huge compensation bills for Thursday's disruption. Consumer group Which? said BA could fall foul of EU rules requiring them to pay up to €600 (about R9 700) for delays that are within the airline’s control.
Which? travel editor Rory Boland said: "This is the latest in a long line of British Airways technical glitches causing delays and cancellations and yet again it’s thousands of passengers who are paying the price - left tired, frustrated and with a lack of information and assistance from the airline."
BA installed a "cost effective" IT system in 2015, but it has repeatedly crashed – costing the company more than £100-million in compensation to passengers.
In August, a meltdown in the airline’s check-in systems caused 12 hours of chaos and left 20 000 passengers stranded.
The airline is also facing a record £183-million fine after hackers stole the personal details of up to half a million passengers last year. BA on Thursday night advised customers to check for possible delays on ba.com but said it planned to operate a full schedule on Friday.