Sheryl Sandberg, Facebook's COO, took to the social network to reassure friends she was not aboard the crashed Asiana jet at San Francisco airport, despite having planned to take that flight.
One member of Ms Sandberg's party, David Eun, was aboard the crashed jet, but swiftly tweeted to announce that he was unharmed.
Ms Sandberg posted a message on her Facebook wall within an hour of the crash to explain that while she, along with family and colleagues, had planned to take the Asiana flight, they had switched to an alternative airline in order to use up air miles.
One member of her party, David Eun, went ahead with the original plan, but swiftly tweeted to announce that he was unharmed.
The Boeing 777 passenger jet, which had flown from Seoul in South Korea, crash-landed at San Francisco Airport on Saturday night, bursting into flames as it appeared to break apart. "Taking a minute to be thankful and explain what happened," wrote Ms Sandberg, who went on to explain that she and most of her party were not among the passengers on the crashed aircraft.
"Thank you to everyone who is reaching out - and sorry if we worried anyone. Serious moment to give thanks," she concluded.
The crashed jet was reported to be carrying around 290 people. Two have been reported dead and dozens injured.
One witness said the back of Asiana Airlines Flight 214 detached while it was touching down, and another described how the aircraft “cartwheeled” down the runway.
Some witnesses said the plane had approached the runway at an "awkward angle" and there was a "loud bang," according to KCBS.
The Federal Aviation Authority (FFA) said San Francisco airport was closed until further notice.
A spokesman said the sequence of events was still unclear, but it appeared the plane landed and then crashed.
Witnesses described how it appeared to be a normal landing, with the landing gear down, but the nose of the plane then went up and they heard a “popping” sound. One passenger said the plane seemed to “wobble” and then begin turning over.
Aviation expert Jim Tillman said it was a "miracle" that so may passengers appeared to have walked off the plane.