(CNN) The National Transportation Safety Board on Monday released a preliminary report on a deadly helicopter crash in New York's East River .

Five people died when the Liberty Helicopters chopper crashed on March 11. The passengers had chartered the trip for a private photo shoot.

The preliminary report does not provide analysis and does not discuss probable cause.

"The information in the report is preliminary and subject to change as the NTSB's investigation progresses," the NTSB said.

Key points from the report include:

The pilot said he gave a safety briefing to passengers before the flight

When the the helicopter crashed, the five passengers drowned because they were unable to break free from harnesses meant to prevent them from falling out.

The pilot told NTSB investigators he provided a safety briefing to the passengers before takeoff. The briefing included a description of how to use a cutting tool to cut their restraints, the pilot said.

During the flight, passengers could turn to face out of the helicopter's open sides to take photos.

When the helicopter was flying along the east side of Central Park, "the front seat passenger turned sideways, slid across the double bench seat toward the pilot, leaned back, and extended his feet to take a photograph of his feet outside the helicopter."

The pilot thought the chopper experienced engine failure

The pilot "observed engine pressure and fuel pressure warning lights and believed he had experienced an engine failure," the report says.

As the pilot made his way to the East River to execute an emergency landing, "he reached down for the emergency fuel shutoff lever, he realized that it was in the off position. He noted that a portion of the front seat passenger's tether was underneath the lever."

The pilot attempted to restart the engine as the helicopter fell toward the river, but the engine "wasn't spooling up fast enough," leading him to turn off the emergency fuel lever again.

According to the NTSB, the fuel flow control lever was found in the off position

The helicopter quickly began to fill with water as it landed in the river. The pilot attempted to unscrew the carabiner of the front seat passenger, but then "decided to egress the helicopter."

An NTSB examination of the helicopter found the engine was not impacted by "oil or fuel leaks, fire, or uncontainment," according to the report.

"The fuel flow control lever was found in the off position. The fuel shutoff lever was found in the open position."

The harness systems and restraint systems were made by different manufacturers

The restraint system for passengers was manufacturer-installed, but the harness system for the passengers was not installed by the helicopter manufacturer, the report states.

The harness system was comprised of off-the-shelf components consisting of a nylon fall-protection harness that was attached at the occupants' back by a locking carabiner to a lanyard, the report says. This allowed the passengers to move in the chopper.

A "small pouch was attached to the harness and contained a cutting tool."

Previous developments

The March 11 crash was the deadliest crash involving a national doors-off helicopter tour, and Liberty Helicopters' third crash in the past 11 years

Liberty Helicopters posted a statement on its website after the crash, saying it was "focused on supporting the families affected by this tragic accident and on fully cooperating with the FAA and NTSB investigations."

In the wake of the crash, the NTSB issued an urgent safety recommendation calling for the Federal Aviation Administration to ban commercial flights' use of harness systems that don't allow for easy release during emergencies.

The FAA issued an order suspending "doors off" flights involving "restraints that cannot be released quickly in an emergency." But NTSB Chairman Robert L. Sumwalt said "the FAA has not outlined how or when they plan to take action."

"Definitive action needs to be taken," he said.</s>NEW YORK — The National Transportation Safety Board has released the preliminary report on the crash of a helicopter earlier in the month.

Five people died after the helicopter they were passengers on went down March 11 in New York’s East River.

Three of the passengers had been taken to hospital with critical injuries after surviving the crash. Two others were killed in the crash.

A sixth person, the pilot, was able to free himself and was rescued.

Officials said, “The preliminary report summarizes the preflight activities, passenger briefing and the sequence of events leading up to the accident as described by the pilot during a post-accident interview.”

The preliminary report is available online here.</s>The National Transportation Safety Board issued its preliminary report Monday in the deadly East River helicopter crash.Five people died on March 11, when the AS-350 operated by Liberty Helicopter tours plunged into the river . The victims were identified as 34-year-old Daniel Thompson and 29-year-old Tristan Hill, both of New York; 26-year-old Trevor Cadigan and 26-year-old Brian McDaniel, both of Dallas; and 29-year-old Carla Vallejos-Blanco, of Argentina. The pilot, 33-year-old Richard "Rick" Vance, was the only one to survive the crash.The preliminary report summarizes the pre-flight activities, passenger briefings and the sequence of events leading up to the accident as described by the pilot during a post-accident interview.The NTSB's examination of the helicopter is detailed in the report, including continuity of flight controls, continuity of drive, condition of rotor blades and the position of controls and switches. Descriptions of the engine, emergency float system, seats and restraint systems are also contained in the report.Related: Expert says simple device may have prevented East River helicopter crash According to investigators:Vance said he he twice told the passengers, as part of two safety briefings, how to use the cutting tools located on the harnesses in the event they needed to cut themselves out. They were using restraints and tethers to allow them to reposition themselves around the chopper to take pictures.The doors were off, and some passengers sat on the side of the chopper floor, with their feet on the chopper's skids.At one point during the flight, the pilot noticed the front passenger's restraint was hanging from the seat. He asked the front seat passenger to put it back on. The pilot said this was not entirely unusual, and passengers have inadvertently done so in the past.Later, the front seat passenger turned sideways and extended his feet outside the helicopter. At that time, the helicopter turned right faster than the pilot expected and began to suffer what appeared at the time to be engine failure.After telling the passengers to get back in their seats as the aircraft began to descend, the pilot took several steps to restart the engine, but his first two tries were unsuccessful. He then began to prepare for a water landing and activated the floats at about 800 feet.He reached down and noticed the emergency fuel shut off level was in the off position, and a portion of the front seat passenger's tether was underneath the lever.He turned the fuel level back on and tried to restart the engine, and it began to work, but he didn't have enough altitude to fully restart. He positioned the lever back to off, hit the water, climbed up onto the belly and called for help.The full preliminary report is available online ----------
The US National Transportation Safety Board releases a preliminary investigative report containing new information on the accident, in which five passengers drowned when they were trapped in the wreckage.