Defense

March 17, 2014

Investigation board determines cause of KC-135 crash in May

The U.S. Air ForceAir Mobility Command has released the results of an accident investigation that examined what caused the May 3, 2013, crash of a KC-135 Stratotanker in the Kyrgyz Republic.

The crew of three, en route from the Transit Center at Manas to Afghanistan on a combat aerial refueling mission, perished in the mishap.

Upon takeoff, a flight control system malfunction, the board found, generated directional instability, causing the aircraft’s nose to slowly drift from side-to-side or “rudder-hunt.” This condition, not fully diagnosed by the crew, progressed into a more dangerous oscillatory instability known as a “Dutch roll.” The board identified that a poor layout of key information in the inflight manual and insufficient crew training contributed to the mishap by detracting from the crew’s ability to act on critical information during their troubleshooting to turn off either of two cockpit switches which may have eliminated the malfunction.

Having not recognized the Dutch roll condition, the crew initiated a left turn to remain on-course along the planned route of flight and used a small amount of left rudder to coordinate the turn. The use of rudder, while in a Dutch roll, increased the aircraft’s oscillatory instability. The ensuing large side-to-side movements of the aircraft varied the crew member’s foot pressure on the rudder pedal which caused inadvertent fluctuations in rudder position. These fluctuating rudder movements, coupled with slight right rudder use while rolling out of the turn, compounded the Dutch roll severity and produced extreme airframe stress that caused the KC-135’s tail section to separate from the aircraft. The subsequent, uncontrollable descent resulted in an in-flight explosion.

“Our hearts go out to the family members and friends of these Airmen,” said Brig. Gen. Steve Arquiette, who led the accident investigation board. “Having attended the memorial service at Manas and later interviewing many co-workers, I know these Airmen were highly regarded and are greatly missed. The investigation team, with the help of our industry and Kyrgyz government partners, pushed through months of intense fact finding for the primary purposes of understanding what happened that day and to honor the crew’s service to our nation.”

The three Airmen who perished are:

  • TSgt. Herman Mackey III, 30, of Bakersfield, Calif.†
  • Capt. Victoria Ann Pinckney, 27, of Colorado Springs, Colo.
  • Capt. Mark Tyler Voss, 27, of Boerne, Texas

A unique combination of six factors – flight control malfunctions, insufficient crew force training, incomplete crew checklist response, use of rudder while in a Dutch roll condition, crew composition, and cumbersome procedural guidance – all came together during the flight’s short 11-minute duration and resulted in this accident.

“The crew encountered a condition that they had not realistically experienced in training, and when coupled with decisions based on their relatively low recent experience levels, were presented with an unrecognized hazardous and difficult situation to overcome,” Arquiette said. “It has been the focus of our investigative team, throughout these months of hard work and travel to the accident scene in the Kyrgyz Republic, to do everything we can to fully understand the facts surrounding this tragic string of events.”

The aircraft was assigned to the 22nd Air Refueling Wing at McConnell Air Force Base, Kan., and was flown by members of the 92nd Air Refueling Wing at Fairchild Air Force Base, Wash. The crew and aircraft were flying out of the 376th Air Expeditionary Wing at the Transit Center Manas.

The report is available on the Air Force Freedom of Information Act Reading Room website, http://www.foia.af.mil/reading/.




All of this week's top headlines to your email every Friday.


 
 

 

Headlines July 6, 2015

News Long wait to come to America for Iraqis, Afghans who served U.S. troops Long wait times and a shortage of available visas for a huge backlog of applications remain major issues for the U.S. government’s Special Immigrant Visa program intended to ease entry to the United States for Iraqis and Afghans who served as...
 
 

News Briefs July 6, 2015

Russian MiG fighter crashes in southern Russia, pilot lives The Russian Defense Ministry says a Russian air force fighter jet has crashed in the south but its pilot ejected safely. The MiG-29 fighter jet went down July 3 near the village of Kushchevskaya in the Krasnodar region, 620 miles south of Moscow. The ministry said...
 
 
Army photograph by Doug LaFon

Army researcher’s interest in robotics leads to innovative device

Army photograph by Doug LaFon Dan Baechle, left, from the U.S. Army Research Laboratory Multifunctional Materials research team, has created a laboratory prototype of a device he designed to sense and damp out arm tremors for A...
 

 
Air Force photograph by TSgt. Joseph Swafford

Pave Hawk maintainers keep rescue birds flying

Air Force photograph by TSgt. Joseph Swafford Airman Joshua Herron, a 41st Expeditionary Helicopter Maintenance Unit HH-60 Pave Hawk crew chief, completes a 50-hour inspection on a Pave Hawk at Bagram Airfield, Afghanistan, Jun...
 
 
Air Force photograph by SrA. Benjamin Raughton

B-52s demonstrate strategic reach

Air Force photograph by SrA. Benjamin Raughton A B-52H Stratofortress is marshalled to a stop at Barksdale Air Force Base, La., after a 44-hour sortie July 2, 2015. Aircrew members and two B-52s from Barksdale AFB’s 96th ...
 
 

Soldier missing from Korean War accounted for

The Department of Defense POW/MIA Accounting Agency announced July 1 that the remains of a serviceman, missing from the Korean War, have been identified and will be returned to his family for burial with full military honors. Army Sgt. Joseph M. Snock Jr. of Apollo, Pennsylvania, was buried July 6, in Arlington National Cemetery. In...
 




0 Comments


Be the first to comment!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>