The Army Black Hawk helicopter, weighing about 18,000 pounds and packed with four crew members and 10 Schofield Barracks soldiers, had emerged from the dust cloud it created on takeoff in northern Iraq when things rapidly went wrong.

According to a final Army report on the subsequent crash that claimed the lives of all aboard, Capt. Corry P. Tyler, the pilot in command, radioed, "I have a tail rotor quadrant light, RTB (return to base), direct back."

A pilot in a smaller two-seat OH-58D Kiowa helicopter had been watching nearby for any possible enemy tracer rounds as Tyler's helicopter and another Black Hawk lifted off sometime before 1 a.m.

Twenty soldiers with the 2nd Battalion, 35th Infantry "Cacti" out of Schofield had been brought in by helicopter the night before for a mission in Multaka, just west of the oil-rich city of Kirkuk.

Now they were being picked up for the ride back to Forward Operating Base Warrior.

Seconds into the flight, at an altitude of about 150 feet and as the helicopter fought for higher air, Tyler made his last radio call.

"1-2 is going down," he said.

Witnesses reported between one and four rotations as the helicopter plummeted back to earth.

The momentary indication that something was amiss was followed by indications far more alarming: dead silence on the ground. Everyone had been killed.

The Army investigation into the crash on Aug. 22, 2007, obtained by The Advertiser through the Freedom of Information Act, and the most detailed account yet of the fatal crash, found that the soldiers suffered blunt force injuries in an impact of 150 Gs.

One G is the force of Earth's gravity. A fighter pilot coming out of a dive can experience up to nine Gs.

It was the greatest single loss of life for the 25th Infantry Division since the Vietnam War, and the worst helicopter crash in Iraq since a CH-53 Super Stallion went down in western Iraq on Jan. 26, 2005. Of 31 killed in that crash, 26 Marines and a sailor were from Kane'ohe Bay.

As the one-year anniversary of the Black Hawk crash approaches this summer, the 224-page investigation doesn't provide a definitive answer as to what caused it.

GOUGED TAIL ROTOR

Amid the grief suffered by families across the U.S., a lawsuit against Black Hawk maker Sikorsky is being prepared in connection with the crash, said the father of one dead soldier.

Lt. Gen. Ray Odierno, the No. 2 U.S. general in Iraq who is set to take over the top job, signed a Feb. 10 "memorandum for record" that says the Corpus Christi Army Depot inspected the downed Black Hawk airframe and discovered a gouged and cut tail rotor shaft.

An "unknown foreign object" in the tail rotor housing traveled aft and became lodged between the housing and the tail rotor drive shaft, causing gouging and cutting damage to the tail rotor, which then failed by sheering forces while under torque, Odierno's memo states.

The Corpus Christi Army Depot report concluded that the failure of the tail rotor drive shaft was the primary cause of the crash. Tail rotor control cable failure was secondary and occurred after the tail rotor problem.

"I find no pilot or crew error," Odierno said. "Origin and responsibility for the foreign object causing damage to the tail rotor drive shaft is not known."

No crews had reported enemy contact in the area, the investigating officer noted, minimizing the possibility of the helicopter being hit by fire.

Richard Harmon, a fire chief in Willoughby Hills, Ohio, who lost his son, Cpl. Joshua S. Harmon, in the crash, said he refuses to look at the accident investigation report because it "talks too much in detail, and I don't want any visions or thoughts of what it could have been like, ever in my life."

He prefers to remember the 20-year-old "with the big goofy grin" who wanted to go to college and then medical school, and who went to Iraq as a medic to take care of fellow soldiers.

"He said, 'I truly believe that we are safer here because we have troops over there, and I want to take care of those troops,' " Harmon said.

Joshua Harmon, like the other Hawai'i soldiers, was at the later part of a 15-month deployment. He had already received a commendation medal for pulling a wounded fellow soldier out of sniper fire and administering mouth-to-mouth resuscitation, his father said.

Richard Harmon knows there was a problem with the tail rotor, and he said he and several other families are pursuing a lawsuit against the Black Hawk manufacturer, the Sikorsky Aircraft Corp., part of the United Technologies Company.

"My son and the 13 others who lost their life in that helicopter, lost their life because at some point in the chain, whether it was Sikorsky, the Army, a maintenance person, whoever made that tail rotor or part, somewhere in that chain, somebody didn't do their job," the elder Harmon said. "Because somebody didn't do their job, we lost 14 wonderful people that day."

"If anything comes out of this at all, I want to make sure that whatever it may be, that I did my part to at least identify what may have caused it, so no other family has to go through this."

SON LOVED THE ARMY

Bill Seideman, the father of Spc. Tyler R. Seideman, who also was aboard the helicopter, would not comment when asked about the findings in the Army investigation.

The Arkansas man said his 20-year-old son loved what he was doing in the Army, and the past nine months have been difficult, but "all things considered, I think we're doing pretty good."

In addition to Joshua Harmon and Tyler Seideman, the Schofield soldiers killed in the crash were Capt. Derek A. Dobogai, Cpl. Jeremy P. Bouffard, Cpl. Phillip J. Brodnick, Cpl. Nathan C. Hubbard, Spc. Michael A. Hook, Sgt. Garrett I. McLead, Staff Sgt. Jason L. Paton and Cpl. Jessy G. Pollard.

The crew, out of Fort Lewis, Wash., included Tyler, the pilot in command; Chief Warrant Officer Paul J. Flynn; Sgt. Matthew L. Tallman; and Spc. Rickey L. Bell. The four soldiers were assigned to the 4th Squadron, 6th Air Cavalry Regiment.

The Carlson Law Firm in Killeen, Texas, said it is exploring legal options on behalf of more than four families, but no lawsuit has been filed.

Paul Jackson, a spokesman for Sikorsky, said on Friday that the Army's safety investigation team did not identify any issues with Black Hawks after the crash that required Sikorsky action.

The Black Hawk has been the Army's workhorse helicopter since 1978, and about 1,500 have been delivered to the Army, as well as another 600 to other countries, accumulating more than 4 million flight hours, according to the company.

Black Hawks were grounded in 1985, 1986 and twice in 1987 because of crashes, and in 1994 the relatives of five soldiers killed in a 1990 crash near Fort Chaffee, Ark., received $9.75 million in a settlement.

In 2000, a federal jury awarded $22.9 million to the families of crew members and survivors in a 1993 Black Hawk accident in Germany.

The fallen Schofield soldiers were part of a 15-month deployment of more than 7,000 Hawai'i soldiers to northern Iraq during 2006 and part of 2007 that ended in October.

All of the helicopters operating in Multinational Division-North were under the control of the 25th Combat Aviation Brigade out of Schofield.

The Army said there were about 170 helicopters operating in the north, and about 70 of those were Black Hawks. Of all the aircraft, about 80 helicopters were from Hawai'i, while the rest came from other commands.

Officials said the airfield at Contingency Operating Base Speicher near Tikrit had more daily aircraft traffic than the airport in Phoenix, Ariz.

According to the Army, in addition to the Black Hawk crash during the deployment, two AH-64 Apache pilots were killed in a weather-related crash in November 2006; two pilots were injured when there was engine failure in an OH-58D Kiowa in March 2007; two Schofield soldiers were killed when their OH-58D Kiowa was shot down in May 2007; and there was one death when another OH-58D Kiowa hit a power line in July 2007.

The U.S. Army Combat Readiness/Safety Center said a total of 10 Sikorsky UH-60 and MH-60s have been lost in Iraq as a result of non-enemy fire and "environmental, materiel or human" causes.

ABOUT THE MISSION

According to the Army investigation into the Aug. 22, 2007, Black Hawk crash, the "small kill team" soldiers of the 2nd Battalion, 35th Infantry were taking part in Operation Baseball Bat IV to destroy or disrupt an improvised explosive device network operating along a supply route outside Kirkuk.

There were four helicopters sent in to pick up and protect the 20-man team, including two Black Hawks and two OH-58D Kiowas.

Both Black Hawks had to do "go-arounds" on the first attempt to land during the nighttime mission because of brownout conditions.

After the crash, "Saber 27" landed, and a pilot from the Kiowa helicopter made his way to the crash site as two medevac Black Hawks were dispatched from Forward Operating Base Warrior.

For unexplained reasons, the Army redacted from the released report all the pilots' names, as well as language it felt was too "graphic." Mission details also were omitted.

The "Saber 27" pilot said in a statement that he reached the downed aircraft after about 8 to 9 minutes, and that no sounds were emanating from it. The overhead engine deck had collapsed and crushed the right side, he said. The pilot said he checked the soldiers he could access, but found no pulses.

After the medevac choppers arrived, the second of the two Black Hawks that took part in the mission landed, and also helped with the recovery.

The air mission commander for one of the OH-58D Kiowas on the scene said the reaction time the crew had from the time the tail dropped and the helicopter spun right, to the time it hit the ground, was "next to impossible."

"I would describe it as almost inhuman to be able to respond to whatever emergency it was that presented this crew," the pilot said.

The UH-60 Black Hawk, with the tail number 06-27077, was manufactured in 2006 and valued at $5 million. The investigating officer found the aircraft "well under" the 22,000-pound maximum gross weight.

An aviation safety officer who had flown the crashed Black Hawk on the mission prior said it was "a sweet aircraft, so smooth that you could barely feel the rotors turning."