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 30, 2014

News: Software to power F-35 running as much as 14 months late - Software needed to operate Lockheed Martin’s F-35 jet, the Pentagon’s costliest weapons system, may be as much as 14 months late for required flight testing, according to a Pentagon review.   Business: Lockheed will turn on JLTV production line In August; 6-D truck...
 
 

News Briefs July 30, 2014

U.S. military deaths in Afghanistan at 2,197 As of July 29, 2014, at least 2,197 members of the U.S. military had died in Afghanistan as a result of the U.S.-led invasion of Afghanistan in late 2001, according to an Associated Press count. At least 1,819 military service members have died in Afghanistan as a result...
 
 
Lockheed Martin photograph by Tom Reynolds

F-35B successfully completes wet runway, crosswind testing

Lockheed Martin photograph by Tom Reynolds F-35B aircraft BF-4, piloted by Lockheed Martin Test Pilot Dan Levin, starts down the runway as part of wet runway and crosswind testing at Edwards AFB, Calif. In an important program ...
 

 
boeing-chinook

Boeing delivers first U.S. Army multiyear II configured Chinook

Boeing July 29 delivered the first multiyear II configured CH-47F Chinook helicopter to the U.S. Army one month ahead of schedule. The delivery was celebrated in a ceremony at the production facility in Ridley Township, Penn. ...
 
 
Army photograph by SSgt. Angela Stafford

Engineers developing safer, more accurate tracer round

Army photograph Tracer rounds enable the shooter to follow the projectile trajectory to make aiming corrections. However, the light emitted by these rounds also gives away the position of the shooter. Engineers at Picatinny Ars...
 
 
NASA photograph by Carla Thomas

Katherine Lott awarded NASA Armstrong employee scholarship

NASA photograph by Carla Thomas Katherine Lott, the recipient of the 2014 NASA Armstrong Employee Exchange Council Joseph R. Vensel Memorial Scholarship, is congratulated by NASA Armstrong center director David McBride. Flankin...
 




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=""> <strike> <strong>