Two men in a plane that crashed during a test flight and sank into the Spokane River near Felts Field Thursday afternoon died after they were underwater for nearly 30 minutes. Witnesses said the plane sounded like it was having engine problems and appeared to lose power as it flew east over Millwood just before 4 p.m. “I knew something wasn’t right,” said David Dexter, who was east of Felts Field when he saw the plane fly overhead, then dip sharply toward the ground. “It sounded weird, like it was struggling.” Dexter said the plane pulled out of the sharp dip, then banked to one side before he lost sight of it. He said it sounded like the engine was whining at high RPMs even while losing altitude. Dexter didn’t hear a crash but a short time later the wail of numerous emergency vehicle sirens told him something was seriously wrong. Spokane County medical examiner’s deputy medical investigator Jim Uttke identified the men late Thursday night as Lyndon Amestoy and Richard Runyon, the Associated Press reported. The spokesman was not authorized to disclose ages or hometowns. The plane crashed into the river around 4 p.m., according to emergency dispatchers, and quickly sank. Spokane Valley Fire Deputy Chief Andy Hail said the pilot and passenger were underwater for about 30 minutes. The plane’s wreckage was submerged about 100 yards upstream and to the east of the Upriver Dam. Records on file with the Federal Aviation Administration indicate the plane is a 1996 Piper Malibu owned by Flying Colors Aviation LLC in Woodland Hills, California. Officials said initial information indicates the plane was considered experimental and had been on a test flight. Among those gathering were rock climbers who had been at the Minnehaha rocks when they saw the plane go down. Richard La Belle and Sam Carter, two of the climbers, said the unusual sound of the engine coming toward the rocks drew their attention. La Belle said he quickly turned and saw the aircraft coming toward the climbing rocks, which are located along Upriver Drive and the Centennial Trail directly north of the crash site. He said the plane banked sharply to the right and was inverted with the cockpit below the wings before the aircraft belly flopped onto the river. “It didn’t pierce the water, it slapped it,” La Belle said, adding that it sank quickly after hitting the water. He and other witnesses ran to the river and stood there helpless, he said. The heavy current and cold water prevented any attempt at rescue without special equipment. The plane was more than 100 feet from shore. La Belle said a few dozen police officers who apparently had been at the police gun range on the south bank of the river near the airfield ran to the shoreline, but they too, could not help. Although a Spokane fire station is located near Felts Field, Assistant Spokane Fire Chief Brian Schaefer said a passing Union Pacific freight train across Waterworks Lane slowed emergency crews from accessing the scene and the boat launch. Dispatch information indicated that crews were delayed by the train for perhaps 10 minutes or more. Schaefer said he eventually turned around and took the Greene Street Bridge to access the site from the other side of the river. When he arrived, Schaefer was in time to watch a wing or tail of the plane fall below the surface. “You’re just completely helpless,” Schaefer said. Emergency crews called Union Pacific to request that the train speed up. “Any delay is frustrating when you have seconds,” Hail said. Later, fire rescue crews in kayaks and an inflatable boat hovered over the wreckage in frigid water. The Spokane County Sheriff’s Office dive team searched the wreckage. A diver brought one man to the surface, said Racheal Hale, who lives nearby. He was put on a raft where firefighters began chest compressions as they took him to shore. By the time the raft came back to the site, divers had pulled the other man from the plane, Hale said. This is the second plane crash in Spokane this year. On Feb. 22, a single-engine Piper Malibu Mirage that had just taken off from Felts Field crashed near the Hamilton Street bridge in east Spokane, killing pilot Michael Clements. Crash investigators are examining the airplane’s fuel. Officials from the National Transportation Safety Board were on their way to Spokane Thursday to investigate the crash. Spokane Valley Fire Department spokeswoman Melanie Rose said the NTSB was planning to raise the plane today . The state Department of Ecology was deployed to the scene and reported via Twitter that a potential of 120 gallons of fuel spilled into the river.