Crash of an ATR72-201 in Tyumen: 33 killed

Date & Time: Apr 2, 2012 at 0735 LT
Type of aircraft:
Operator:
Registration:
VP-BYZ
Flight Phase:
Survivors:
Yes
Schedule:
Tyumen - Surgut
MSN:
332
YOM:
1992
Flight number:
UT120
Country:
Region:
Crew on board:
4
Crew fatalities:
Pax on board:
39
Pax fatalities:
Other fatalities:
Total fatalities:
33
Captain / Total flying hours:
2602
Captain / Total hours on type:
2522.00
Copilot / Total flying hours:
1825
Copilot / Total hours on type:
1765
Aircraft flight hours:
35523
Aircraft flight cycles:
49663
Circumstances:
On 01.04.2012 the the UTAir Air Division 1 crew (based at Surgut AP) was conducting a scheduled passenger flight UTA-119 on the АТR 72-201 VP-BYZ A/C from Surgut to Tyumen. The landing at Tyumen (Roschino) AP was performed at 17:41 (23:41 local time). Descending for landing at Roschino (Tyumen) AD was conducted in extended cloudiness with icing conditions. According to the FDR records, the flight crew used the aircraft ice protection system. At the time of flight UTA-119 landing at Roschino (Tyumen) AD the weather was as follows: surface wind 090°-7 m/s, visibility 1600 m, showers of moderate snow with rain, significant cumulonimbus (5-7 oct.) clouds, fractonimbus, cloud base at 140 m, temperature + 0.2°C, dew point + 0.2°C, QFE 735 mmhg (980 hPa), friction coefficient 0.6; moderate icing at cloud layer from 140 m to 4800 m. Forecast for landing: tempo visibility 500 m, showers of heavy snow with rain, vertical visibility 90 m. Weather at Roschino (Tyumen) AD at day time on 01.04.2012 and at night from 01.04.2012 to 02.04.2012 was formed by the cyclone trough forward part with the widespread precipitation area associated with warm front. A passage of the warm front through Roschino (Tyumen) AD was expected in the period from 20:00 to 21:00, with a temperature of 0°C and relative humidity 100% precipitations were fallen from the cumulonimbus and fractonimbus clouds in form of showers of snow with rain. Visibility in precipitations was 1200–1600 m with individual charges of heavy wet snow with visibility 600–700 m and vertical visibility 100 m. Precipitation was followed by east wind 9–10 m/s, direction 90–110°, with individual gusts up to 13–14 m/s. This direction of wind remained till 21:00. After the passage of front through the region of Roschino (Tyumen) AD, at 21:05 the surface wind changed its direction to the west 250° – 260° with gradual increase of wind speed from 2–4 m/s to 7–10 m/s. Precipitation in the form of showers of moderate snow with rain at Roschino (Tyumen) AD went on till 22:00, 01.04.2012. From 22:00, 01.04.2012 to 01:00, 02.04.2012 precipitation turned into showers of slight snow with rain with a temperature of 0°C and relative humidity 100%. According to the observations of weather stations situated at a distance of about 200– 250 km from Roschino (Tyumen) AD and affected by the cyclone on 01.04.2012 as well as on 02.04.2012 storm detecting information was sent to the Roschino (Tyumen) AD AMC about glaze-ice accretion of wet snow. After the landing the A/C was placed at stand 3 heading to the air terminal (MH 30°). According to the flight shift work schedule, the crew left for rest to the Liner Hotel at Roschino AP and had a rest till 23:30 (05:30 local time). After having their rest, the crew members arrived to the AP and started the preflight preparation for the UTA120 scheduled passenger flight from Tyumen to Surgut with visiting AMC where at 00:15 they got weather briefing and documentation. The Nizhnevartovsk AD had been appointed as the alternate AP. At the end of the weather briefing the PIC received Form АВ-11 No.1 and put his signature at the sheet of the "Log of flight crews’ weather briefings at Tyumen-Roschino AMC" indicating the flight number and the A/C number. The weather forecast and actual weather at the departure AD, destination AD and alternate AD as well as their technical conditions did not imply any hazard for the flight operation. At 00:20 the crew passed a medical examination at the AP pre-start medical station and was cleared for the flight. According to the intra-airport radio conversation, around the same time the PIC made his decision to fly. After the medical examination, the F/O visited the aeronautical information office and received a navigator’s briefcase and flight plan; which is recorded in pertinent logbooks. Further, the crew continued the preflight preparation in the briefing room. According to the load documents there were 39 passengers, 133 kg of cargo, 143 kg of passengers’ luggage, and 1 kg of mail registered for the UTA120 flight. The fuel on board was 2000 kg, the A/C TOW was 18730 kg, the A/C weight balance was 30.72% mean aerodynamic chord. The TOW and weight balance were inside the AFM (FCOM) limitations. According to an avionics technician's statements the crew arrived to the A/C around 00:30. By the external observation video camera records it can be seen that the PIC performed the preflight inspection very briefly. He lingered for a few minutes by the right engine then moved along the fuselage sides, then stopped by the left main gear, and finally went into the cockpit. The after-inspection FTLB entry made by the PIC was: "LC PERFORMED BY CDR", the PIC also put the time of inspection which was 00:40 and quantity of fuel 2000 kg. There were no remarks made against the A/C condition in the FTLB. By the records of the external observation video camera, it can be seen that at 01:13 the boarding had been completed and the entrance door was closed. So, the A/C had been remaining at the AD under the influence of precipitations in the form of rain and wet snow with ambient temperature around zero degrees Celsius and wind velocity more than 10 m/s for more than 7 hours. There was no de/anti-icing treatment performed for the A/C before the flight. At 01:20 the flight crew performed the engine start, and after that passed through the Before Taxi checklist. At 01:24:46 the flight crew obtained clearance for holding position. At 01:32:08 after clearance for lineup position the flight crew reported: “Lining up”. At 01:32:58 the A/C started taking off. The takeoff was performed with flaps extended at 15°. The A/C lift-off occurred at 01:33:28 with a speed of around ≈127 kt. At 01:33:56 at height 600 ft2 and speed of 135 kt the A/P was engaged. At 01:34:00 at height 640 ft and speed of 139 kt the flaps retraction was started. At 01:34:08 after the retraction had been completed, at 690 ft and at a speed of 150 kt uncommanded development of right bank started. At 01:34:10 the A/P was disengaged. The bank angle reached around 40° to the right within 3 s and after that was counteracted by ailerons and rudder deflection. Further, the A/C banked to the left, which the flight crew was not able to compensate with full deflection of ailerons to the right. The A/C collision into terrain occurred at 01:34:35 with a pitch down angle ≈11°, left bank angle ≈55° and vertical rate of descent over 20 m/s. The ASL elevation of the accident area is about ≈110 m. The accident resulted in the A/C full destruction and partial damage by the ground fire. From the 43 persons onboard 4 crew members and 29 passengers were killed. Others sustained serious injuries.
Probable cause:
The immediate cause of the АТR 72-201 VP-BYZ aircraft accident was the PIC’s decision to takeoff without de/anti-icing treatment despite the fact that snow and ice deposits were present on aircraft surface and were discovered by the crew members during taxi which resulted in degradation of aircraft aerodynamic performance and stall during climbing after takeoff as well as inability of the crew to recognize stall and, consequently, failure to undertake recovery procedure. The aircraft stall occurred at the operational angles of attack right after flaps retraction with engaged autopilot before stall warning system activation and was caused by the loss of the wing lift effectiveness due to takeoff with non-removed ground icing. The system cause of the accident were shortcomings in ground handling activities and staff training in UTAir-Technik that became possible because of absence of due monitoring by the Technical and Operation Supervising Directorates of UTAir airline for compliance with airline requirements regarding ground handling and aircraft ground icing protection which resulted in erroneous evaluation of aircraft conditions by the PIC and aircraft mechanic (the shift head kept himself aloof from monitoring mechanic’s activities) after the aircraft has been on ground in icing conditions for a long time and in release the aircraft to fly without de/anti-icing treatment.
The contributing factors were:
- The shortcomings in the UTAir safety management system, which contains, all in all, general issues only and is not adopted for the implementation of Airline activities in particular areas, which did not allow to reveal and correct existing safety risks in a timely manner.
- The shortcomings in the UTAir-Technic quality management system, resulted in neglecting of certain requirements of the UTAir ground handling management manual regarding staff training and monitoring for aircraft de/anti-icing treatment which led to the situation when not sufficiently-qualified staff performed the evaluation of the aircraft surface conditions and made the decision on need for the aircraft to be de-iced/anti-iced.
- The absence at the time of the accident of basic regulations in force that establish state requirements for ground handling (de/anti-icing treatment in particular) including staff training and organization licensing.
- The shortcomings in crew members initial and recurrent training as far as the danger of ground icing, its influence on the aircraft aerodynamic performance together with aircraft anti-icing system operation features and design are concerned that did not allow the crew to make the only appropriate decision to return for de-icing/anti-icing treatment after the observation of the snow and ice contamination on the wing after anti-icing system activation in de-icing mode while taxiing for takeoff.
- The methodological imperfection of the crew computer based and simulator training programs concerning the prevention of aircraft stall, identification of approach to stall and taking timely actions for recovery.
- The increasing need for number of flight crews to perform highly growing flights schedule which, with ineffective SMS, resulted in flight instructor work deficiencies during PIC training and absence of PIC skills to take correct decisions and to strictly comply with the regulations in force.
- The possible fatigue of the crew members due to the violation of the work and rest balance while performing split flight shifts together with a large number of unused days-off.
Final Report:

Crash of an Antonov AN-24RV in Strezhevoy: 7 killed

Date & Time: Jul 11, 2011 at 1156 LT
Type of aircraft:
Operator:
Registration:
RA-47302
Survivors:
Yes
Schedule:
Tomsk - Surgut
MSN:
5 73 103 02
YOM:
1975
Flight number:
IK9007
Country:
Region:
Crew on board:
4
Crew fatalities:
Pax on board:
33
Pax fatalities:
Other fatalities:
Total fatalities:
7
Captain / Total flying hours:
4570
Captain / Total hours on type:
4064.00
Copilot / Total flying hours:
9476
Copilot / Total hours on type:
5100
Aircraft flight hours:
48489
Aircraft flight cycles:
32783
Circumstances:
The twin engine aircraft departed Tomsk Airport at 1010LT on a flight (callsign IK9007/SP5007) to Surgut, carrying 33 passengers and a crew of four. About an hour and 26 minutes into the flight, the left engine's 'chips in oil' warning light came on. About eight minutes later, a burning smell was noticed in the cockpit and the captain decided to divert to Nizhnevartovsk Airport. During the descent, the left engine caught fire. Its propeller was feathered and the crew decided to divert to Strezhevoy Airport. But as the fire could not be extinguished, the captain eventually attempted an emergency landing in the Ob River. Upon landing, the aircraft broke in two and came to rest in shallow water. Seven passengers were killed while all other occupants were rescued.
Probable cause:
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.
Final Report:

Ground fire of a Tupolev TU-154B-2 in Surgut: 3 killed

Date & Time: Jan 1, 2011 at 1525 LT
Type of aircraft:
Operator:
Registration:
RA-85588
Flight Phase:
Survivors:
Yes
Schedule:
Surgut - Moscow
MSN:
83A588
YOM:
1983
Flight number:
KGL348
Country:
Region:
Crew on board:
8
Crew fatalities:
Pax on board:
126
Pax fatalities:
Other fatalities:
Total fatalities:
3
Captain / Total flying hours:
12202
Captain / Total hours on type:
2780.00
Copilot / Total flying hours:
3775
Copilot / Total hours on type:
3279
Aircraft flight hours:
32354
Aircraft flight cycles:
13147
Circumstances:
Ready for taxi, the crew started the engines when a short circuit occurred and a fire erupted in the rear compartment. The evacuation of all 134 occupants was initiated but three passengers died while 32 others were seriously injured. The aircraft was totally destroyed by fire. The OAT was -29° C at the time of the incident.
Probable cause:
A short circuit emerged while the aircraft generators were connected to the aircraft's electrical system after start-up of the engines, via an APU. The short circuit caused a strong fire in the generators compartment in the tail which spread rapidly through the fuselage. The cause of the fire was an electrical arc produced by electrical currents exceeding ten to 20 times the nominal loads when two generators not synchronized with each other were brought online but got connected together instead of being connected to parallel busses. The following contributing factors were identified:
- Poor technical conditions of contacts TKS233DOD responsible for connecting the generators with the electrical busses, that were damaged by prolonged operation without maintenance. A contact normally open was welded and fractured insulation material moved between contacts that are normally closed. These abnormal contact positions led to the connection between #2 and #3 generators.
- Differences in the schematic diagrams of generator 2 and generators 1 and 3. When the switch is moved from "check" to "enable" with no delay in the "neutral" position generator 2 is brought online without time delay which leads to increased wear of normally closed contacts in the TKS233DOD unit.
- The specific design of the electrical systems to ensure power supply to each bus from either the APU or either engine integrated drive generator.
Final Report:

Crash of a Tupolev TU-134A in Samara: 6 killed

Date & Time: Mar 17, 2007 at 1140 LT
Type of aircraft:
Operator:
Registration:
RA-65021
Survivors:
Yes
Schedule:
Surgut - Samara - Belgorod
MSN:
48390
YOM:
1976
Flight number:
UT471
Country:
Region:
Crew on board:
7
Crew fatalities:
Pax on board:
50
Pax fatalities:
Other fatalities:
Total fatalities:
6
Aircraft flight hours:
35154
Aircraft flight cycles:
22611
Circumstances:
The aircraft departed Surgut on a flight to Belgorod with an intermediate stop in Samara, carrying 50 passengers and 7 crew members. While descending to Samara-Kurumoch Airport, weather conditions worsened and the visibility was below minimums. After the approach checklist was completed, the crew lowered the landing gear, selected flaps down at 30° and continued the approach. In poor visibility, the aircraft descended below the MDA until it struck the ground at a speed of 320 km/h and crashed 304 metres from the runway threshold and 95 metres to the left of its extended centerline. The aircraft came to rest upside down and partially burned. Six passengers were killed, 21 other occupants were injured and 30 people escaped uninjured. At the time of the accident, the visibility was estimated to be 150 metres with an RVR of 200 metres for runway 23 and a vertical visibility of 300 feet in freezing fog.
Probable cause:
The decision of the crew to continue the descent below MDA in below minimums weather conditions until the aircraft impacted ground and crashed.
The following contributing factors were identified:
- Organizational, technical and procedural deficiencies in the work and interactions between the met office and ATC services as well as from the crew,
- Deficiencies in the standards and technical documentation of the Samara Airport that made it impossible for ATC to inform the crew on a timely manner about the readings from the KRAMS-4 weather station that indicated a deterioration of the weather conditions below airport minimums,
- At decision height, in the absence of reliable visual contact with the approach lights and airport environment, the flight crew failed to initiate a go-around procedure,
- ATC failure to use the full capability of the radar equipment because of contradictions in the relevant standards and procedures documents,
- Poor crew coordination and their delay in executing a missed approach procedure,
- Lack of unified federal regulations covering flight operations, ATC, met and other services, taking into account both domestic and international experience in flight safety.

Crash of a Tupolev TU-134A in Surgut: 20 killed

Date & Time: Feb 27, 1988 at 0607 LT
Type of aircraft:
Operator:
Registration:
CCCP-65675
Survivors:
Yes
Schedule:
Minsk – Kuybyshev – Tyumen – Surgut
MSN:
2 35 17 05
YOM:
1972
Flight number:
SU7867
Country:
Region:
Crew on board:
6
Crew fatalities:
Pax on board:
45
Pax fatalities:
Other fatalities:
Total fatalities:
20
Aircraft flight hours:
18900
Aircraft flight cycles:
12656
Circumstances:
Following an uneventful flight from Kuybyshev, the crew initiated the descent to Surgut Airport by night. The visibility was reduced due to marginal weather conditions. On approach, ATC instructed the pilot to modify his trajectory and to follow the glide as the aircraft deviated to the left. At this time, it is believed that the captain got distracted. After the crew passed the decision height, the captain continued the approach despite the fact he did not establish any visual contact with the runway lights and failed to initiate a go-around. At a height of 38 meters and a speed of 286 km/h, the aircraft passed 50 meters to the left of the threshold and the captain decided to continue. ATC instructed the crew to go-around when, one second later, the aircraft touched the ground of a snowy field some 714 meters past the runway threshold and 113 meters to the left of the runway. With a positive acceleration of 4,8 g, the aircraft lost its right wing and came to rest upside down, bursting into flames. 31 people were injured while 20 others were killed, among them the copilot.
Probable cause:
It was determined that the crew adopted a wrong approach configuration and took the decision to continue the approach after passing the decision height without establishing any visual contact with the runway lights. The following contributing factors were reported:
- The captain got distracted,
- The crew failed to initiate a go-around procedure,
- The approach lights were not activated,
- The visibility was reduced due to the night and marginal weather conditions,
- Poor flight preparation,
- Poor approach planning,
- Inaccurate information were transmitted to the crew related to weather conditions and visibilty.

Crash of an Antonov AN-24RV in Tarko-Sale: 17 killed

Date & Time: Dec 9, 1977 at 1925 LT
Type of aircraft:
Operator:
Registration:
CCCP-47695
Flight Phase:
Survivors:
Yes
Schedule:
Tarko-Sale - Surgut
MSN:
27307602
YOM:
1972
Flight number:
SU134
Country:
Region:
Crew on board:
5
Crew fatalities:
Pax on board:
18
Pax fatalities:
Other fatalities:
Total fatalities:
17
Aircraft flight hours:
11791
Aircraft flight cycles:
8486
Circumstances:
Following a night takeoff from Tarko-Sale Airport, while climbing at a height of 120 meters and a speed of 295 km/h, the captain requested flaps up when the airplane started to descend with a rate of nine meters per second. The aircraft then rolled to the right by an angle of 30° and struck trees at a speed of 365 km/h before crashing 2,889 meters past the runway end. Four crew members and 13 passengers were killed while six other occupants were seriously injured. The aircraft was destroyed.
Probable cause:
The exact cause of the accident could not be determined with certainty. Eyewitnesses reported a red light facing the aircraft just prior to the accident but it was confirmed there was no other traffic in the vicinity of the airport at the time of the accident. It is possible that the red light may be a fire or a possible flare.

Crash of a PZL-Mielec AN-2 in Surgut: 14 killed

Date & Time: Nov 1, 1974 at 1456 LT
Type of aircraft:
Operator:
Registration:
CCCP-70766
Survivors:
No
Schedule:
Khanty-Mansiysk - Surgut
MSN:
1G132-21
YOM:
1971
Flight number:
SU662
Country:
Region:
Crew on board:
2
Crew fatalities:
Pax on board:
12
Pax fatalities:
Other fatalities:
Total fatalities:
14
Aircraft flight hours:
2591
Aircraft flight cycles:
3477
Circumstances:
Following an uneventful flight from Khanty-Mansiysk, the crew was cleared to continue the approach to runway 25 when he encountered marginal weather conditions with low clouds (130 meters above the ground) and limited visibility. While on approach at an altitude of 150 metres, the single engine airplane collided with a Mil Mi-8T. Registered CCCP-25686, it just took off from Surgut Airport bound to Nefteyugansk with 21 passengers and three crew members on board. Following the collision, both airplanes crashed in a wooded area, 600 meters from each other. Both machines were destroyed and none of the 38 occupants survived the collision.
Probable cause:
The collision was the consequence of wrong decisions on part of ATC at Surgut Airport who cleared the Antonov AN-2 crew to continue the descent while they actually had no idea of his real position. Following an accumulation of negligences, ATC failed to coordinate both movements, failed to inform both crews about the presence of a second aircraft in the traffic pattern and authorized the crew of the helicopter to take off while they did no have any idea about the exact position of the Antonov. The lack of visibility caused by the presence of low clouds remained a contributing factor, as well as the fact that the Antonov AN-2 crew continued the descent below weather minima.

Crash of an Antonov AN-12B in Surgut: 7 killed

Date & Time: Jan 31, 1971 at 0441 LT
Type of aircraft:
Operator:
Registration:
CCCP-12996
Flight Type:
Survivors:
No
Schedule:
Tyumen - Surgut
MSN:
00 347 403
YOM:
1970
Country:
Region:
Crew on board:
6
Crew fatalities:
Pax on board:
1
Pax fatalities:
Other fatalities:
Total fatalities:
7
Aircraft flight hours:
391
Circumstances:
The airplane was completing a cargo flight from Tyumen to Surgut, carrying one passenger, six crew members and a load of 12 tons of herring from the Pacific. On final approach by night, at an altitude of 400 meters and a speed of 330 km/h, the captain requested 'flaps 15' when the airplane became unstable and rolled left and right. Few seconds later, the airplane entered a nose down attitude, reached the speed of 395 km/h and crashed in a left bank of 90° into an icy lake located 13,6 km from the runway threshold. The aircraft was totally destroyed and all sven occupants were killed.
Probable cause:
Loss of control caused by an excessive accumulation of ice on wing tips. The following factors were considered as contributing:
- Severe icing conditions,
- Misuse of the de-icing systems by the crew, especially with regard to air bleeding of the engines.

Crash of an Antonov AN-12B in Surgut: 14 killed

Date & Time: Jan 22, 1971 at 2136 LT
Type of aircraft:
Operator:
Registration:
CCCP-11000
Flight Type:
Survivors:
No
Schedule:
Omsk - Surgut
MSN:
5 3 436 10
YOM:
1965
Country:
Region:
Crew on board:
12
Crew fatalities:
Pax on board:
2
Pax fatalities:
Other fatalities:
Total fatalities:
14
Aircraft flight hours:
5626
Aircraft flight cycles:
2578
Circumstances:
The aircraft was completing a cargo flight from Omsk to Surgut, carrying two passengers, a crew of 12 (among them six reserve members) and a load of 12 tons of various construction equipments. While approaching Surgut Airport by night and icing conditions, at an altitude of 400 meters and a speed of 330 km/h, the pilot lost control of the airplane that crashed in flames 15 km short of runway. The aircraft was destroyed and all 14 occupants were killed.
Probable cause:
There were severe icing conditions at the time of the accident and the crew activated all de-icing equipment. Nevertheless, it appears that following the failure of a valve, the de-icing equipment was inoperative. An excessive accumulation of ice on the fuselage, the wings and all four engines caused the loss of control.

Crash of an Antonov AN-24B in Nizhnevartovsk: 24 killed

Date & Time: Oct 13, 1969 at 1727 LT
Type of aircraft:
Operator:
Registration:
CCCP-47772
Survivors:
Yes
Schedule:
Tyumen – Surgut – Nizhnevartovsk
MSN:
79901405
YOM:
1967
Flight number:
SU227
Country:
Region:
Crew on board:
4
Crew fatalities:
Pax on board:
52
Pax fatalities:
Other fatalities:
Total fatalities:
24
Aircraft flight hours:
2756
Aircraft flight cycles:
2298
Circumstances:
The crew started the approach to Nizhnevartovsk Airport by night and marginal weather conditions. Due to erroneous calculations, the aircraft was not properly aligned on the approach path and the captain decided to make a go-around. Six minutes later, he initiated a second approach. On short final, ATC asked the pilot if he has the runway in sight. As the answer was positive, the crew was cleared to land. Less than a minute later, the airplane struck tree tops, stalled and crashed in flames in a wooded area located 1,092 meters short of runway threshold. 32 occupants were injured while 24 others were killed, among them the copilot and a flight attendant.
Probable cause:
It was determined that the propellers went inadvertently into reverse when the crew activated the engine de-icing system. It was later discovered during investigations that there was a conception error on this type of aircraft between the de-icing systems and the thrust reversal systems that could activate simultaneously. Nevertheless, when control was lost, the flaps were deployed in an angle of 17° instead of 38° as prescribed, which was considered as a contributing factor.