“Hang on,” were the final words from the pilot of a Hawaii Life Flight medical transport plane that spiraled down into the ocean off Kaupo, Maui, Dec. 15, killing all three crew members aboard, according to a preliminary report on the crash released today by the National Transportation Safety Board.

The report provides a timeline and other details surrounding the ill-fated flight but does not offer a probable cause for the crash, a finding that is not expected for months. However, a transmission from the pilot, who has been identified as Brian Treptow, suggests the trouble began roughly 20 minutes into the flight from Kahului Airport as he was navigating his initial approach to the Waimea-Kohala Airport on Hawaii island.

Another pilot who was flying in the area in a small private aircraft reported seeing the Hawaii Life Flight airplane start to turn right and then enter “a spiraling right descending turn, which steepened as the descent increased,” the NTSB report said. The pilot told investigators he watched the airplane continue its descent until it impacted the water and he lost sight of its lights.

The NTSB report says the Raytheon Aircraft Co. C90A twin-engine, turbine-powered airplane sank in an area of open ocean with an estimated water depth of 6,000 feet. Its wreckage and the three crew members — who included flight nurse Courtney Parry and flight paramedic Gabriel Camacho — have not been recovered.

The Hawaii Life Flight aircraft departed from Kahului Airport at 8:53 p.m. Dec. 15 en route to pick up a patient at the Waimea-Kohala Airport for transport to Honolulu. At 9:03 p.m., Treptow reported the aircraft had reached 11,000 feet above sea level. A Honolulu air traffic controller asked if the pilot could climb to 13,000 feet, and Treptow responded in the affirmative, the NTSB report said.

The flight followed an east-southeasterly heading along Maui’s northern coastline before turning southbound along the predetermined flight route. At 9:08 p.m. Treptow was further instructed to turn right, and a minute later was told to descend to 12,000 feet and a minute after that to 8,000 feet, with the pilot acknowledging each instruction from the controller, the report said.

At 9:12 p.m., the controller gave Treptow another heading and cleared the flight to fly direct to the “initial approach fix” for the approach to the Waimea-Kohala Airport, and the pilot acknowledged, the NTSB report said.

A minute later, when the controller tried to confirm he was flying as directed, Treptow replied, in part, referring to the plane’s registration number, “Uhh, 13GZ is off navigation here … we’re gonna … we’re gonna give it a try.”

The controller offered further instructions for a right heading and to maintain altitude at 8,000 feet, the report said, but just 11 seconds later came the final radio transmission from the pilot, “Hang on.”

An extensive search was launched by the U.S. Coast Guard and portions of airplane wreckage were found floating near and in the vicinity of the flight’s last known location, the report said. The search was officially suspended Dec. 19.

The NTSB report said the airplane was equipped with a cockpit voice recorder and an underwater acoustical beacon, as well as a cockpit-mounted Airborne ImageRecording System.

In a statement today, a Hawaii Life Flight spokesperson said the company needs “to respect the investigative process” and is referring any questions about the crash to the NTSB.

“Hawaii Life Flight is deeply appreciative of the continued support from the community and our partners in care during this challenging time,” the statement said. “The NTSB has released their preliminary factual report on this accident. We anticipate the final report to take a year or more … .”

NTSB Preliminary Report – Hawaii Life Flight by Honolulu Star-Advertiser on Scribd