(CNN) - When a Liberty Helicopters chopper plunged into the frigid East River on Sunday night, onlookers were stunned. But it was actually the third time in 11 years one of the company's helicopters crashed in New York.
The latest accident killed all five passengers on board. The pilot, who managed to free himself, was the sole survivor.
Liberty Helicopters describes itself as "the largest and most experienced helicopter sightseeing and charter service in New York City," with a fleet of 10 Airbus helicopters.
But it hasn't said much about the latest crash, deferring to federal authorities.
"We are focused on supporting the families affected by this tragic accident and on fully cooperating with the FAA and NTSB investigation," the company said on its website. "These agencies have asked us to respect the investigative process by referring all press inquiries to them for any further comment."
Sen. Chuck Schumer of New York has called for the Federal Aviation Administration to suspend Liberty's license "until their safety record and the circumstances of this latest crash are fully assessed," his office said.
Here's what we know about the company's previous two crashes since 2007:
2009: Crash with another plane kills 9 people
Investigators said a Liberty Helicopters chopper flew up to the altitude of a small private plane when the two aircraft crashed over the Hudson River in August 2009.
Nine people were killed, including all six on board the helicopter and three on the private plane.
The FAA said the helicopter and small plane were communicating on different radio frequencies "and were not aware of each other's positions."
Three months after the crash, the FAA tightened control of the airspace, separating low-altitude local aircraft flights over the Hudson River, such as a sightseeing helicopter, from flights going through the river airspace, such as the private plane.
2007: Helicopter crashes into Hudson River
In July 2007, a Liberty sightseeing chopper suffered a rotor blade separation midflight and crashed into the Hudson River.
All passengers were wearing inflatable life vests, and the pilot said she deployed pop-out floats, the National Transportation Safety Board said. The helicopter made an emergency landing in the water.
Neither the pilot nor the seven passengers were seriously injured.
2018: Details emerge from most recent crash
While the cause of Sunday's crash remains unclear, the pilot told investigators a passenger's bag may have inadvertently hit the emergency fuel shutoff button, a senior law enforcement official said.
The pilot, 33-year-old Richard Vance, has no prior accident nor incident history with the FAA, agency spokesman Jim Peters said.
He said the Eurocopter AS350 that Vance was flying had no incident history with the FAA.
More helicopter crashes than airplane crashes?
If it sounds like there are more helicopter crashes than airplane crashes, there's a reason for that.
"Helicopter companies tend to have higher rates of accidents than fixed-wing operations, in part because they're harder to fly," former NTSB managing director Peter Goelz said.
For example, helicopter pilots have to master the difficult technique of hovering.
"And they tend to fly in more congested areas that may have more challenging wind and weather patterns," Goelz said. "So you do tend to have higher accident rates."