Learjet crash probes icing and turbulence

The National Transportation Safety Board detailed the final moments of a Learjet 60 that crashed in Greenacres, Florida, on Sunday. The aircraft departed Austin-Bergstrom International Airport bound for North Eleuthera Airport in the Bahamas. All nine people on board died in the fiery impact.

Investigators focused on icy conditions and turbulence as primary factors. NTSB member Tom Chapman stated that the crew reported light clear ice and moderate turbulence to air traffic control at approximately 12:47 p.m. Eastern. At that time, the plane was at 35,000 feet with altitude deviations of about 700 feet. The outside temperature was minus 47 degrees Celsius.

The crew requested clearance to climb to 37,000 feet after encountering precipitation. Less than 30 seconds later, the aircraft transmitted a mayday call. Chapman noted that the transmission included the phrase 'we are in an overspeed condition, descending.' The remainder of the communication was unintelligible.

The plane struck the ground in a Palm Beach County neighborhood around 1 p.m. EST. Debris scattered over an area extending about a half-mile from the impact site. Tim Monville, a senior investigator with the NTSB, confirmed that one man on the ground was injured. He was in a vehicle leaving the adjacent area and sustained a leg injury. Monville said he was not aware of other ground injuries.

Wreckage analysis suggests the jet began breaking apart before it hit the ground. Chapman said the agency has evidence of in-flight breakup. The aircraft was equipped with a voice recorder, and investigators are working to locate the device to determine if it remains functional.

The NTSB said it would review safety trends for the aircraft model and the specific plane's history. Chapman stated there is no indication of a history of this type of accident with this model of aircraft. The agency said it would not speculate about the cause at this time.

A 20-year-old co-pilot was among the fatalities. Investigators did not comment on her role during the flight or whether she was at the controls. Officials have not yet publicly identified the victims. The NTSB said local authorities will handle victim identification.

The investigation is expected to take several days. The NTSB is working with the Palm Beach County Sheriff's Office, the FAA, air traffic control, Learjet Inc., and weather experts. Investigators are interviewing witnesses and asking the public to contact the agency at witness@NTSB.gov with photos or video of the crash. Anyone who finds debris is asked not to touch it and to contact authorities immediately.

Chapel said these are the first steps in a lengthy investigatory process. The agency extended condolences to the families and thanked first responders for their efforts.