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Investigation into crash that killed Tech. Sgt. Briggs reveals helicopter struck cable

12/05/2018 4:55 PM |

The HH-60G Pave Hawk helicopter that crashed in western Iraq last March, killing Riverhead native Dashan Briggs and six other service members, struck a galvanized steel cable strung horizontally between two 341-foot high towers, according to a United States Air Force Aircraft Accident Investigation Board report.

The report, the first detailed account of the crash, listed pilot error as a key factor. The investigation concluded that the pilots misinterpreted aircraft navigation displays, which caused the formation to overfly the intended destination. That led the aircraft to descend into an unplanned location. The cable, which was not clearly visible under the nighttime conditions, became entangled in the helicopter’s main rotor assembly.

No navigation or equipment problems were reported, the investigation concluded, nor were there any civilian injuries or damage to private property. The $49 million helicopter was destroyed on impact when it crashed near the city of Al-Qa’im.

“Based on the estimated impact acceleration forces, the crash was not survivable,” the report says.

Tech. Sgt. Briggs, Maj. Christopher Zanetis of Long Island City, Master Sgt. Christopher Raguso of Commack and Capt. Andreas O’Keeffe of Center Moriches were all members of the 106th Rescue Wing in Westhampton. The three other service members killed, who were pararescue team members, were Master Sgt. William Posch of Indialantic, Fla., Staff Sgt. Carl Enis of Tallahassee, Fla., and Capt. Mark Weber of Colorado Springs, Colo.

The report does not refer to any of the crew members by name, only by their title.

The mission on March 15, 2018, was to move two HH-60G Pave Hawk helicopters to a new location where they would be closer to respond in support of an upcoming operation. If any personnel or assets needed rescue in the upcoming mission, it would be the crews assigned to the 332nd Air Expeditionary Wing that would respond.

The crew of the 46th Expeditionary Rescue Squadron was six to seven weeks into their deployment and the work to that point had been described as “unremarkable” and “slow.”

Planning for the mission began on the morning of March 15. During a flight briefing that lasted between 30 and 45 minutes, the crews covered every aspect of the mission, including the weather, the flight route, possible threats or hazards, a mid-air refueling and other topics. The Operational Risk Management was assessed as low.

Clear skies were reported, although with no moon that night, combined with the dust and haze, visibility was three to four miles. The aircrew members used night vision goggles mounted to their helmets. About a half-hour into the flight, the helicopter, which was the lead in the formation, rendezvoused with an HC-130 for a mid-air refuel. That process took less than six minutes. From there, the next waypoint was the landing zone. 

Over the next 4 1/2 minutes, the helicopters proceeded toward the landing zone while starting a shallow descent from the refueling altitude. During that time period, the pilot was interrupted multiple times during navigation, including communications with the accompanying helicopter and requests for information from the crew and the Joint Terminal Attack Controller. The JTAC alerted the pilot to towers in the immediate area surrounding the landing zone.

By the time that communication ended, the helicopters had flown slightly to the northeast of the landing zone. The non-navigation tasks reduced the pilot’s ability to identify the error in the flight.

As the helicopter descended, the crew identified and avoided a set of power lines and four towers. Two towers were on the left and two on the right. After seeing those obstacles, the co-pilot decided to level off at 300 feet.

An overhead view, looking southeast, of the area where the helicopter crashed last March in Iraq. A cable connected to the towers, pictured at the top, was responsible for the crash. (U.S. Air Force photo)

Seconds before striking the cable, the co-pilot turned the helicopter left to avoid the north tower at its one o’clock position. The helicopter was traveling approximately 143 miles per hour when it struck the cable, which was strung between the towers about 1,000 yards apart. Immediately following the cable impact, the pilot and co-pilot “swiftly and calmly” switched control of the helicopter. The co-pilot made the call to land. At the same moment, the aircraft suffered “catastrophic structural failures” and could not be controlled before impact with the ground.

The accompanying helicopter was just under a half-mile away at the time of the crash. That helicopter turned right to avoid a tower and the light generated by the crash illuminated another tower and cables in front of them. The crew of that helicopter was able to climb to avoid the hazards. It was the first and only time either crew could visibly see the cables strung between different sets of towers.

The towers and cables in the area limited the crew’s ability to immediately land near the crash site. About 20 minutes after the crash, coalition ground forces arrived to secure the crash site. The second helicopter landed about 700 meters from the site about 40 minutes after the crash and two pararescuemen made their way on foot to assist. At the same time, a third helicopter landed with additional rescue crews.

The pararescuemen and a combat rescue officer worked with the coalition forces to locate and recover the bodies of the fallen airmen. They used fire extinguishers from the two helicopters and ground vehicles to battle the inferno. The ammunition on board had caused added explosions.

A statement of opinion written by Brig. Gen. Bryan Radliff, president of the Accident Investigation Board, listed several factors as contributing to the crash.

• The mission planning had created a flight route that contained additional waypoints beyond the intended landing zone. It’s unlikely the crew would have flown past the landing zone if the route had terminated at the landing zone, he wrote.

• A breakdown in communication between the crew and the two helicopters in the formation to detect and communicate the navigation error. “The [accompanying helicopter] failed to adequately provide the proper navigation support of overflying the intended [landing zone],” Brig. Gen. Radliff wrote.

• Low illumination conditions that evening rendered the night vision goggles insufficient to detect the cables. The helicopter was also not equipped with any sensors to identify cables strung between towers. The HH-60G did have a Wire Strike Protection System, but it was ineffective in this case because the cable did not get pulled through any of the wire cutters, which are located between the front tires and fuselage and between the fuselage and main rotor.

Toxicology tests on the crew members did not reveal any substances as a factor, nor was there any evidence lifestyle factors played a role in the crash. 

Two weeks after the crash, the bodies of three members of the 106th Rescue Wing, including Tech. Sgt. Briggs, 30, returned home for a service at Francis S. Gabreski Airport in Westhampton Beach. The dignified arrival came one week after the fallen service members were taken to Dover Air Force Base in Delaware.

Following a funeral service on March 29, a procession traveled from the Westhampton Beach Volunteer Fire Department to Pulaski Street School, Riverhead Middle School and the high school, where students lined the street to pay respects to the 2007 graduate. The procession continued to Calverton National Cemetery, where Tech. Sgt. Briggs was laid to rest.

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Top caption: An HH-60 Pave Hawk helicopter assigned to the 55th Expeditionary Rescue Squadron sits on the flight line at Al Asad Air Base in Iraq in 2017. It’s the type of helicopter that crashed last March and resulted in the death of seven service members, including Riverhead native Dashan Briggs. (U.S. Air Force photo/Master Sgt. Benjamin Wilson photo)

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