The National Transportation Safety Board (NTSB) is launching investigations into two separate helicopter crashes over the weekend, which left at least one person dead.
A crash on the South Side of Chicago injured all four people onboard the medical helicopter, according to fire officials. Paramedics transported the patient in the helicopter via the Eurocopter 135 air ambulance in critical condition. The pilot and two other crew members were transported in stable condition.
The pilot may have saved lives by maneuvering the descending chopper into a grassy area and avoiding the major highways nearby, officials said. The helicopter landed Saturday evening on its belly and was smoking but not on fire, Lynda Turner, the deputy district fire chief, said.
"The pilot did an excellent job of landing a helicopter that was in an emergency situation," Turner said at a press conference.
On Sunday, an R44 helicopter with only the pilot on board crashed into a housing complex in Williamsburg, Virginia, causing the building to catch on fire, authorities said. Eyewitness video showed flames and thick smoke engulfing the entire two-story building.
Virginia State Police identified the lone death in the accident as 91-year-old Jean Lonchak Danylko. She was inside the building during the crash.
The pilot is still missing.
The causes for both accidents have yet to be determined. An NTSB spokesperson said the probes could take weeks or months.
The two accidents come in an era where helicopter crashes continue to be at a record low, according to the latest Federal Aviation Administration (FAA) statistics.
Since 2006, the number of worldwide civil helicopters has grown by 30 percent, according to government records, but the number of accidents has decreased by 30 to 50 percent.
Between 2001 and 2005, there were 7.97 helicopter accidents per 100,000 flight hours in the United States. In 2016 -- the year in which the latest statistics are available -- there were 3.45 accidents per 100,000 flight hours, the lowest on record.