United States Air Force - USAF (since 1947)

The Board President could not find clear and convincing evidence to determine the exact cause of the engine power loss. He did find evidence to conclude that several factors combined to significantly contribute to the Mishap Airplane (MA) landing partially gear down. Specifically, a defensive system alert, the aircraft's low altitude and airspeed at the time of the malfunction, and the decision to respond to the alert at low altitude and airspeed combined to result in the MA landing partially gear down. All MA systems and performance were normal prior to the defensive system alert. An undetermined malfunction occurred during the defensive reaction that caused three of the MA's four engines to stabilize at an RPM (60%) which was not sufficient to maintain flight and the low altitude and airspeed at the time of the malfunction limited the time available for situation analysis and recovery. The Mishap Crew (MC) had never been exposed to a loss of three or four engines on takeoff in the C-130H2 simulator which resulted in an emergency situation the MC had not seen before at a low altitude and airspeed. Checklist actions taken by the MC did not recover the engines and the Mishap Pilot (MP) appropriately performed a limited power, controlled descent, and forced landing resulting in only minor injuries.

Conjunction of poor weather conditions and crew errors. The aircraft encountered windshear with downburst on descent and the crew ignored warnings. The combination of the following human factors placed the aircraft in a dangerous weather environment: poor mission planning, inattention, complacency, lack of procedural knowledge and restricted vision.

The crew’s failure to take appropriate action after allowing the aircraft to get 15 knots [17 mph] slow over the runway threshold. Had either pilot taken proper action to go around upon seeing the airspeed bleeding away by advancing power on both engines, this mishap could have been avoided.

The collision between the TU-154 and KC-135R aircraft was clearly an accident and not the result of any intentional conduct. The Accident Investigation Board, convened by AMC, determined that the accident was caused by the Kyrgyzaeronavigation air traffic controller who cleared a civilian airliner for takeoff without verifying that the KC-135R was clear of the runway. In addition to the air traffic controller, the AIB found evidence of several contributing factors involving the KC-135R aircrew, conflicting published airport notices, and a tower liaison employed by the U.S. Government to facilitate communication between the tower and U.S. aircrews. Although the AIB found the air traffic controller primarily at fault, the U.S. KC-135R crew and tower liaison shared responsibility for ensuring the KC-135R cleared the runway to a safe location following landing. The accident might have been avoided had any of them exercised better awareness of their situation.
In conclusion, the AIB determined the principal cause of the mishap was the Kyrgyzaeronavigation controller clearing the TU-154 for takeoff without verifying that KC-135R was clear of the runway, there was evidence the following factors also contributed to the mishap:
- The Kyrgyz air traffic controller's instruction to vacate at taxiway Golf after dark conflicted with a published Notice to Airmen (NOTAM) that limited that taxiway's use to daylight hours. The contractor safety liaison (LNO) employed by the U.S. Air Force to facilitate communication between its aircrews and Kyrgyz controllers did not clarify the apparent discrepancy.
- After questioning the Kyrgyz controller's instruction to vacate the runway at taxiway Golf, the LNO instructed the KC-135R crew to hold short of Alpha. The mishap KC-135R crew misperceived the LNO's instructions and responded "holding short of Golf." The LNO failed to catch the read-back error.
- The Kyrgyz controller failed to maintain awareness of the KC-135R's location.
- The LNO failed to maintain situational awareness and intervene when the controller's actions endangered the KC-135R and aircrew.
The KC-135R is assigned to the 92nd Air Refueling Wing, Fairchild Air Force Base, Wash. While deployed at Manas AB, the KC-135R and its aircrew were assigned to U.S. Central Command's 376th Air Expeditionary Wing, flying missions supporting coalition aircraft over Afghanistan.

Based on clear and convincing evidence, the Board President determined the primary cause of the mishap was the pilots' and flight engineers' failure to use the number three, fully operational, engine; the instructor's and primary flight engineer's failure to brief, and the pilots' failure to consider or utilize a 62.5 or 40% flap setting (instead of a 100% flap setting); and the pilots' attempt at a visual approach to runway 32, descending well below a normal glidepath for an instrument-aided approach or the normal VFR pattern altitude of 1,800 ft. There is substantial evidence that a contributing factor to this mishap was MP1's failure to give a complete approach briefing, in that, nonstandard factors, configuration, landing distance, and missed approach intentions were not addressed.

The accident investigation board determined that the crew's loss of situational awareness placed the aircraft in too low a climb with respect to the surrounding mountainous terrain. Responding to the situation, the crew did not use all available power and stalled the aircraft during a turning climb. This resulted in a loss of aircraft control and almost immediate crash.