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« Ответ #81 : 09.07.2015, 16:59:16 pm » |
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The ASC confirmed, one person on the ground received serious, another minor injuries. 39 passengers and 4 crew on board of the aircraft perished, 13 passengers and 1 crew member survived with serious injuries, 1 passenger survived with minor injuries.
The ASC reported that engine #1 showed no anomaly and no unusual maintenance whatsoever.
The ASC reported, that engine #2 also showed no anomaly with no unusual maintenance. To investigate the reason for the uncommanded autofeather of the right hand engine the investigation performed a continuity check on the wiring harness between Auto Feather Unit (AFU) and the #1 torque sensor, all measurements were within permitted limits. Slight water ingress was found when the connectors were removed, but the connector pins were dry.
Both AFUs as well as another AFU, where another uncommanded autofeather had occurred after GE-235, were sent to the manufacturer for further examination. AFU #1 passed all tests by the manufacturer. AFU #2 of the accident aircraft however failed the continuity test, the resistance between pins J and H fluctuated when the cable was moved by hand, reaching a minimum value of 0.35Ohm. Pins J and H are connected to the torque sensor. Following extensive testing and revised testing methodes the soldering of pins inside the 90 degrees J2 connector were examined under an optical microscope as well as a scanning eletronic microscope, which discovered coarsening and cracking in the stress zone adjacent to pin/solder interface, further away the solder microstructure was intact.
The wiring harness to the torque sensor was tested extensively with no anomaly identified.
The readout of BITE memory of AFU #2 showed no erors prior to the accident flight following a maintenance reset. AFU #2 recorded a torque of engine #2 at less than 25% torque over a duration of more than 30 seconds which triggered the autofeather command.
The ASC reported that video surveillance from dash board cameras of vehicles were helpful to the investigation in addition to surveillance videos from two tall buildings nearby. The videos show the aircraft passed near one of the buildings (without contact), the first contact of the aircraft was with the taxi.
8 sets of seats (2 seats per set) in the aft fuselage, with their associated structures including seat belts, remained intact and in position, the other 28 sets were dislocated, most of them badly damaged and twisted.
Impact forces were predominantly from front to back and caused multiple traumatic injuries. The fatalities were caused by those traumatic injuries as well as drowning.
The ASC reported that there were two captains, Captain A (42, ATPL, 4,914 hours total, 3,151 hours on ATR-72-500, 250 hours on ATR-72-600) was pilot in command occupying the left hand seat being pilot flying, Captain B (45, ATPL, 6,922 hours total, 5,687 hours on ATR-72-500, 795 hours on ATR-72-600) occupied the right hand seat and was pilot monitoring, a first officer complemented the crew occupying the observer's seat, the first officer (63, ATPL, 16,121 hours total, 7,911 hours on MD-80s, 5,306 hours on ATR-72-500) was in conversion training to ATR-72-600 with 8 hours on the aircraft type.
Опубликовано с avherald.com
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