Asia

The probable causes of the crash were:
Following the inflight shut down of engine number one and feathering of the number one propeller the longitudinal (roll) control of the aircraft was lost due to load-bearing properties of the left wing and possible damage to the left hand aileron control wiring resulting in the aircraft's uncontrolled excessive roll to the left and subsequent impact with terrain. The fire started in the tail section of the #1 engine nacelle and spread forward and onto the wing. The fire was most likely fed by fuel leaking from a fuel line connection to the low pressure fuel pump at engine #1, the fuel most likely ignited due to contact with hot engine parts. Due to the disintegration of the aircraft and fire damage it was not possible to establish the location of fuel leaks and the cause with certainty. The inability of the fire suppression system to extinguish such a fire in its early stages as well as the lack of checklists/guidelines in the aircraft's flight manual for fuel leaks inside the engine nacelle contributed to the delay of more than 2 minutes to shut the engine down. The mountainous terrain underneath the aircraft, low level overcast cloud and lack of time due to continued fire did not permit the crew to select a proper site for an emergency landing.

The probable causes of the accident were the failure of the crew to go around and the descent well below decision height without visual reference to landmarks when the aircraft approached the airfield in weather conditions below the captain's, aircraft's and airfield's minima and in dangerous/adverse weather phenomena like thunderstorm, heavy rain and severe turbulence as well as the lack of appropriate response and required actions following terrain awareness warning system alerts resulted in a controlled flight into terrain, collision with obstacles and the destruction of the aircraft.
Contributing factors:
- the crew underestimated the weather conditions at the destination airport thus taking an erroneous decision to attempt an approach in thunderstorm and heavy rain showers,
- unsatisfactory meteorological support of the flight, the dispatcher and later air traffic control provided information about visibility, cloud and wind data that did not correspond to actual conditions that were significantly worse than minimums required,
- clearance for the approach by air traffic control despite the presence of dangerous weather phenomena (thunderstorm, heavy rain) at the aerodrome, which did not correspond to the standard operating procedures at Blagoveshchensk,
- inadequate staffing with a first officer who was performing his first flight after a prolonged leave without proper preparation and training,
- unsatisfactory crew interaction and the failure to adhere to standard operating procedures, especially the call outs of approaching decision height, the absence of a decision by the commander to continue the landing or go-around and the lack of action to recommend/initiate a go around by the first officer.

The Interstate Aviation Committee (MAK) released their final report in Russian concluding the probable causes of the accident were:
The catastrophe of the AN-24 RA-47302 occurred when ditching became necessary due to a fire in the left hand engine's nacelle. The destruction of the aircraft and loss of life was caused by collision with underwater obstacles that the crew could not anticipate or avoid. The fire in the left hand engine nacelle was caused by the fracture of a centrifugal breather releasing an air-fuel emulsion into the engine compartment as well as a delayed reaction to shut the engine down by the crew following an magnetic chip detector indication together with indications of oil pressure fluctuations, a burning smell and a low oil pressure indication. A delay in indicating engine vibrations to the crew as result of degradation of the engine vibration sensoring equipment, most likely caused by changes of the rotor speed of the engine as result of the aft bearing failure of the compressor rotor and/or misalignment of the sensor, which probably influenced the decision of the crew to shut the engine down with a delay. Cause of the fracture of the centrifugal breather was the destruction of the impeller due to prolonged exposure to hot air-fuel emulsion due to the failure of the aft compressor rotor support bearing. It was not possible to determine the cause of the destruction of the aft compressor rotor support bearing due to significant secondary damage. Most likely the destruction was caused by misalignment such as:
- Incorrect assembly of support parts mating with the compressor rotor during on-condition engine repairs,
- Or deviations from required geometry of support parts mating with the compressor rotor.
Contributing factors were:
- Psychological unpreparedness of the captain to shut the engine down due to lack of experience with the aircraft on one engine inoperative
- Late detection of the fire and as a consequence late attempts to extinguish the fire, it was however not possible to establish why the fire was detected late due to lack of objective information about the performance of the fire alarm systems.

Impact with a high swell during landing followed by a high bounce and hard landing resulting in both float attachments being damaged and detached with a major structural damages. Major contributing factor was higher than normal touch down speed due to abnormal landing configuration.
Contributing factors:
- Selection of inappropriate landing site (channel) and landing direction (tail wind) based on surface conditions present at that time,
- Simulation of multiple emergencies,
- Abnormal landing configuration (flaps at zero) for single engine landing,
- Time pressure to complete the training and return to commercial operations.

When the aircraft approached the airfield in weather below minimums for the aerodrome descending on autopilot at a fixed vertical speed, crew failed to decide to go around in absence of visual contact with approach lights and landmarks and permitted the aircraft to descend below minimum descent altitude, which led to impact with trees and the ground in controlled flight.
Following factors were considered as contirbutory:
- unsatisfactory crew resource management by the commander who effectively removed the first officer from the control loop in the final stages of the accident flight and who subordinated himself to the navigator showing increased activity however in the state of mild alcoholic intoxication.
- the navigator was in the state of mild alcoholic intoxication
- unjustified weather forecasts by height of cloud base, visibility and severe weather including fog as well as the non-conformity of weather data of Petrozavodsk Airport transmitted to the crew 30 and 10 minutes prior to estimated landing.
- Failure to use indications by the ADFs and other devices of the aircraft while using indications by an unapproved satellite navigation system KLN-90 in violation of flight manual supplements for the TU-134.

The probable cause of the accident could be attributed to departure of the aircraft from controlled flight due to an external weather related phenomenon, mishandling of controls, spatial disorientation or a combination of the three.

Engine failure in flight for undetermined reasons.

FINDINGS:
1. The aircraft was airworthy prior the accident. There is no evidence that the aircraft had malfunction during the flight.
2. The crew had valid flight license and medical certificate. There was no evidence of crew incapacitation.
3. In this flight the SIC acted as Pilot Flying until the PIC took control of the aircraft at the last part of the flight.
4. According to company operation manual (COM), in a VMC (Visual Meteorological Condition), a “minimum, minimum” EGPWS alert while the approach was not stabilized should be followed by the action of abandoning the approach.
5. The cockpit crew did not conduct any crew approach briefing and checklist reading.
6. As it was recorded in the CVR during the final segment of the flight, both crews member were looking out-side to look for the runway. It might reduce the situational awareness.
7. At the final segment of the flight, the FDR recorded as follows:
• The approach was discontinued started at 376 feet pressure altitude (250 feet radio altitude) and reached the highest altitude of 585 feet pressure altitude. While climbing the aircraft was banking to the left reaching a roll angle of 38 degree. The torque of both engines was increased reaching 70% and 82% for the left and right engine respectively.
• During the go-around, the flaps were retracted to 5 and subsequently to 0 position, and the landing gears were retracted. The aircraft started to descend, and the pitch angle reached 13 degree nose down.
• The rate of descend increased significantly reaching about 3000 feet per minute, and finally the aircraft crashed into the shallow sea.
8. The rapid descent was mainly a result of a combination of situations such as high bank angle (up to 38 deg to the left) and the flaps retracted to 5 and subsequently to 0 position, and also the combination of other situations: engine torque, airspeed, and nose-down pitch.
9. The ERS button was determined in the CRUISE mode instead of TOGA mode. This had led the torque reached 70% and 82% during discontinuing the approach.
10. The flaps were retracted to 5 and subsequently to 0, while the MA-60 standard go-around procedure is to set the flaps at 15.
11. There was limited communications between the crew along the flight. This type of interaction indicated that there was a steep trans-cockpit authority gradient.
12. The SIC was trained in the first three batches which was conducted by the aircraft manufacturer instructor and syllabus, while the PIC was trained by Merpati instructor using modified syllabus. Inadequacy/ineffectivity in the training program may lead to actions that deviated from the standard procedure and regression to the previous type.
13. The investigation found that the Flight Crew Operation Manual (FCOM) and Aircraft Maintenance Manual (AMM) used non-standard English Aviation Language. This finding was supported by a review performed by the Australian Transport Safety Bureau (ATSB).
OTHER FINDINGS:
1. The DFDR does not have the Lateral and Longitudinal acceleration. These two parameters which were non safety related items were mandatory according to the CASR parts 121.343 and 121.344, and at the time of the MA 60 certification, the CCAR 121 did not require those two parameters.
2. Due to impact forces and immersion in water, the Emergency Locator Transmitter (ELT) did not transmit any signal.
FACTORS:
Factors contributed to the accident are as follows:
1. The flight was conducted in VFR in condition that was not suitable for visual approach when the visibility was 2 km. In such a situation a visual approach should not have been attempted.
2. There was no checklist reading and crew briefing.
3. The flight crew had lack of situation awareness when tried to find the runway, and discontinued the approach.
4. The missed approach was initiated at altitude 376 feet pressure altitude (250 feet radio altitude), the pilot open power to 70% and 82% torque followed by flap retracted to 5 and subsequently to 0. The rapid descent was mainly caused by continuously increase of roll angle up to 38 degree to the left and the retraction of flaps from 15 to 0 position.
5. Both crew had low experience/flying time on type.
6. Inadequacy/ineffectivity in the training program may lead to actions that deviated from the standard procedure and regression to the previous type.

Failure of the brakes is suspected.