Two serious incidents on Boeing 787 Dreamliners within hours of each other could force yet another major safety rethink for the beleaguered corporation, as its share price plunged.
A plane which caught fire at Heathrow Airport, caused the closure of the airport's runways, and another of the same make was forced to turn back to Manchester Airport due to technical problems.
The emergency services are dealing with an "incident" at Heathrow, involving an Ethiopian Airlines plane, which is a Boeing 787 Dreamliner.
Meanwhile, Thomson Airways said a Dreamliner flight from Manchester to Florida had to be diverted back to the UK earlier due to a "technical issue".
The Boeing design has been plagued with issues, having been due to launch in 2008 but delayed because of ongoing safety fears about its lithium ion batteries until 2011.
A picture of the Ethiopian Airlines plane at Heathrow
Airline experts have pointed out, however, that pictures of the plane show fire damage to the outside of the plane, near its tail — not close to any of the battery locations.
Thomson Airways became the first British carrier to operate the Dreamliner earlier this week, and is taking delivery of eight of the planes.
Ethiopian Airlines said its plane had been parked at Heathrow for more than eight hours before smoke was detected.
A statement from the airline said: "Smoke was detected from Ethiopian Airlines B787 aircraft...which was parked at London Heathrow airport for more than eight hours.
"The aircraft was empty when the incident was observed. The cause of the incident is under investigation by all concerned."
The US National Transportation Safety Board said that it was sending a representative to London to assist authorities with their investigation into the fire.
Arrivals and departures were suspended from Heathrow but runways have now been re-opened.
Shares in Boeing have fallen heavily as investors reacted to news of the fire, according to the BBC. In midday trading on Wall Street shares in the aircraft manufacturer had sunk almost 7%.
A Boeing spokesman said: "We're aware of the event. We have Boeing personnel on the ground at Heathrow and are working to fully understand and address this."
An Air Accidents Investigation Branch spokesman said: "We are aware of the incident at Heathrow and have sent a team to investigate."
The Metropolitan Police said the fire was "being treated as unexplained."
In first year of service, at least four Boeing 787 Dreamliners suffered from electrical system problems stemming from their batteries, including an electrical fire aboard an All Nippon Airways 787, and a similar fire found by maintenance workers on a landed Japan Airlines 787 at Boston's Logan International Airport.
Fifty Dreamliners were grounded in January because of persistant issues with the batteries, later modified with new batteries.
But British operators have so far been undeterred, and plan to roll out their own services on Dreamliners.
British Airways is taking delivery of the first two of its 24 Dreamliners, Virgin Atlantic said it "remains committed" to taking on the first of its 16 Dreamliners in September next year.
A spokeswoman said: "Virgin Atlantic is in regular communication with Boeing to understand all the technical issues around the aircraft and the airline remains committed to taking delivery of 16 Boeing 787-9 Dreamliners from autumn 2014.
"We are confident that Boeing and the relevant authorities are working hard to ensure that the appropriate action is being taken."
Three flights bound for Heathrow from Lagos, Shanghai and Delhi were diverted to London Gatwick due to the disruption, Virgin Atlantic said.