Shares of Boeing plunged as much as 7 percent after reports of a fire on an Ethiopian Airlines Dreamliner at London Heathrow Airport on Friday.
The internal fire took place on a Boeing 787 parked at Heathrow, according to an airport spokesman. The plane was on a remote parking stand, so there were no passengers on board and it was not scheduled to fly any time soon. The airport was closed to air traffic during the incident.
In a tweet from Boeing's Twitter account, the company stated, "We're aware of the 787 event @HeathrowAirport and have Boeing personnel there. We're working to fully understand and address this."
A spokesman for Boeing said the company would provide updates when they are able to do so.
The NTSB said it was sending a representative to investigate the issue at Heathrow Airport.
Also on Friday, Thomson Airways, based in Crawley, England, said one of its Dreamliner flights from England to the U.S. had to turn back after experiencing a technical issue.
"Thomson Airways can confirm that flight TOM126 travelling from Manchester to Sanford, Florida experienced a technical issue and the aircraft returned to Manchester Airport, as a precautionary measure," the company's statement says. "Passengers have disembarked and our dedicated team of engineers are now inspecting the aircraft. Our customers will be moved to an alternative aircraft to ensure they get away on their holiday as soon as possible. The safety of our customers and crew is of paramount importance and we would like to apologise for the delay caused."
Neal Dihora, equity analyst with Morningstar, said Boeing's stock is weak because investors fear the fire could be related to the battery issue from January 2013.
Until mid-April, the Federal Aviation Administration and other regulators grounded the global Dreamliner fleet for three months due to a battery catching fire on a plane parked in Boston, and another emergency landing in Japan. The batteries and their cases were redesigned as a result of the grounding.
Rick Seaney, CEO of FareCompare.com, said this incident would only lead to greater problems for Boeing if it leads to another grounding of the 787 feet.
"Given the pent up demand for the Dreamliner experience from fliers, I wouldn't expect their enthusiasm to wane," he said. "However, to the extent this triggers a follow-on grounding of the 787 fleet it certainly might mute the carriers' hankering for this aircraft."
Since launching commercially in 2011, there have been problems with the aircraft, dubbed The Dreamliner, around the world.
On June 23, a Boeing 787 made an emergency landing in Houston after a brake indicator light incorrectly indicated there was an issue.
After the plane landed safely, United Airlines said, "Following standard operating procedures, as a precautionary measure, the flight landed in emergency status."
After the Houston emergency landing, Dihora said some mishaps are expected with new airplane launches.
"I don't think it says much about the future of the aircraft," he said. "We tend to focus a lot on the Dreamliner because it is new and it has experienced larger issues in the past. Safety is the primary concern with all things in the air, so 'emergency' landings with new aircraft get increased following."
On June 12, an All Nippon Airways Dreamliner flight was canceled when an engine would not start. On the previous day, a Japan Airlines flight to Singapore returned to Tokyo because of a deicing problem. On June 18, a Denver to Tokyo flight was diverted because of an oil indicator light.