Crash of a Cessna T207A Turbo Stationair 7 in Page: 1 killed

Date & Time: May 10, 2014 at 1545 LT
Operator:
Registration:
N7311U
Survivors:
Yes
Schedule:
Page - Page
MSN:
207A-0395
YOM:
1977
Location:
Crew on board:
1
Crew fatalities:
Pax on board:
6
Pax fatalities:
Other fatalities:
Total fatalities:
1
Captain / Total flying hours:
6850
Captain / Total hours on type:
48.00
Aircraft flight hours:
14883
Circumstances:
During a local sightseeing flight, the pilot noticed that the engine had lost partial power, and he initiated a turn back toward the airport while troubleshooting the loss of power. Despite the pilot's attempts, the engine would not regain full power and was surging and sputtering randomly. The pilot entered the airport's traffic pattern on the downwind leg, and, while on final approach to the runway, the airplane encountered multiple downdrafts and wind gusts. It is likely that, due to the downdrafts and the partial loss of engine power, the pilot was not able to maintain airplane control. The airplane subsequently landed hard short of the runway surface and nosed over, coming to rest inverted. The reported wind conditions around the time of the accident varied between 20 and 70 degrees right of the runway heading and were 14 knots gusting to greater than 20 knots. In addition, a company pilot who landed about 8 minutes before the accident reported that he encountered strong downdrafts and windshear while on final approach to the runway and that he would not have been able to reach the runway if he had a partial or total loss of engine power. Postaccident examination of the airframe and engine revealed no evidence of any preexisting mechanical malfunctions or failures that would have precluded normal operation. The engine was subsequently installed on a test stand and was successfully run through various power settings for several minutes. The reason for the partial loss of engine power could not be determined.
Probable cause:
The pilot's inability to maintain aircraft control due to a partial loss of engine power and an encounter with downdrafts and gusting crosswinds while on final approach to the runway. The reason for the partial loss of engine power could not be determined because postaccident examination revealed no mechanical malfunction or failure that would have precluded normal operation.
Final Report:

Crash of a BAe 125-700A in Saltillo: 8 killed

Date & Time: Apr 19, 2014 at 1946 LT
Type of aircraft:
Registration:
XA-UKR
Survivors:
No
Site:
Schedule:
Cozumel - Saltillo
MSN:
257191
YOM:
1982
Country:
Crew on board:
2
Crew fatalities:
Pax on board:
6
Pax fatalities:
Other fatalities:
Total fatalities:
8
Captain / Total flying hours:
12984
Captain / Total hours on type:
4470.00
Copilot / Total flying hours:
620
Copilot / Total hours on type:
67
Aircraft flight hours:
6166
Aircraft flight cycles:
4699
Circumstances:
Following an uneventful flight from Cozumel, the crew initiated an ILS/DME2 approach to Saltillo-Plan de Guadalupe Airport Runway 17. On final, the crew encountered poor visibility due to foggy conditions. Despite he was unable to establish a visual contact with the runway, the crew continued the approach and descended below the MDA when the aircraft collided with power cables and crashed on a building located in an industrial park, 1,448 metres short of runway. The aircraft was destroyed by impact forces and a post crash fire and all eight occupants were killed. The building was also destroyed by fire. At the time of the accident, the horizontal visibility was estimated to be 800 metres with a vertical visibility of 200 feet.
Probable cause:
The accident was the consequence of the decision of the crew to continue the approach below MDA in IMC conditions until the aircraft collided with power cables and impacted ground. The following contributing factors were identified:
- The approach was unstable,
- The decision of the crew to continue the approach below MDA without visual contact with the runway,
- Poor safety culture by the operator,
- The crew failed to comply with procedures related to an ILS/DME2 approach to runway 17,
- Lack of crew resources management,
- The crew failed to respond to the GPWS alarm,
- The crew did not monitor the altitude during the final approach,
- Poor weather conditions with a visibility below minimums,
- Inadequate maintenance controls,
- The crew failed to follow the SOP's.
Final Report:

Crash of a Quest Kodiak 100 in Doyo Baru: 2 killed

Date & Time: Apr 9, 2014 at 0940 LT
Type of aircraft:
Operator:
Registration:
PK-SDF
Flight Phase:
Survivors:
Yes
Schedule:
Doyo Baru – Ninia
MSN:
100-0049
YOM:
2011
Country:
Region:
Crew on board:
1
Crew fatalities:
Pax on board:
6
Pax fatalities:
Other fatalities:
Total fatalities:
2
Captain / Total flying hours:
25530
Captain / Total hours on type:
1752.00
Aircraft flight hours:
1752
Aircraft flight cycles:
2211
Circumstances:
A Kodiak-100 aircraft, registered PK-SDF, on 9 April 2014 was being operated by PT. Adventist Aviation Indonesia as non-schedule flight from Doyo Baru Airstrip with intended destination of Ninia Airstrip, Papua. On board in this flight were 7 persons consist of one pilot and six passengers. This flight was the fourth flights for the pilot who has performed flights from Doyo Baru (DOB) – Puldamat (PUL) at 2138-2228 UTC; Puldamat (PUL) –Soya (SOY) at 2243-2247 UTC; Soya (SOY) – Doyo Baru (DOB) at 2256-2344 UTC. The flight time to destination was estimated of 1 hour with cruising altitude of 10,000 feet and the fuel on board were sufficient for 4 hours flight time. Doyo Baru Airstrip located at approximately 10 NM North West of Sentani Airport (WAJJ). Air traffic movement to and from Doyo Baru Airstrip was controlled by Sentani Tower controller. At 0015 UTC, the pilot contacted to Sentani Tower controller, requested for start engine and clearance to fly to Ninia. The requests were approved and to report when ready for departure. At 0021 UTC, the pilot reported to the Sentani Tower controller ready for departure from Doyo Baru Airstrip. The Sentani Tower Controller instructed the pilot to hold to wait an aircraft took off from Sentani Airport. At 0024 UTC, the pilot received clearance for takeoff with additional traffic information and to report after airborne. At 0027 UTC, Sentani Tower controller has not received reports from the PK-SDF pilot and tried to call but was not responded. After several observations toward Doyo Baru area and did not see PK-SDF aircraft, The Sentani Tower controller reported to the Chief Section of Sentani Tower Air Navigation. At 0030 UTC, The Chief Section of Sentani Tower Air Navigation clarified the condition of PK-SDF aircraft to one of Indonesian Adventist Aviation pilot in Doyo Baru and obtained information that the aircraft had experienced in accident during takeoff at Doyo Baru. An engineer after received the information went to the accident site and saw appearance of white smoke came out from the side of the river which was known as the accident aircraft located. After arrived at the accident site the engineer saw the Adventist’s staffs and local people tried to extinguish the fire on the aircraft engine by throwing some water and used two fire extinguishers while some people moved the passengers from the wreckage. Two occupants including the pilot were fatally injured and five other passengers were seriously injured. All occupants were taken to Yowari Hospital (Rumah Sakit Umum Daerah – RSUD Yowari).
Probable cause:
Contributing Factors:
- The failure to airborne was due to the aircraft was not in correct takeoff configuration which required wing flap 20° while the flap was found at approximately 6° position during impact.
- The actions to recover the situation by selection of emergency power and flap were not proper for particular condition.
Final Report:

Crash of a Piper PA-31-350 Navajo Chieftain in Lanai: 3 killed

Date & Time: Feb 26, 2014 at 2130 LT
Operator:
Registration:
N483VA
Flight Phase:
Survivors:
Yes
Schedule:
Lanai – Kahului
MSN:
31-7552124
YOM:
1975
Location:
Crew on board:
1
Crew fatalities:
Pax on board:
5
Pax fatalities:
Other fatalities:
Total fatalities:
3
Captain / Total flying hours:
4570
Aircraft flight hours:
12172
Circumstances:
The airplane departed during dark (moonless) night conditions over remote terrain with few ground-based light sources to provide visual cues. Weather reports indicated strong gusting wind from the northeast. According to a surviving passenger, shortly after takeoff, the pilot started a right turn; the bank angle continued to increase, and the airplane impacted terrain in a steep right bank. The accident site was about 1 mile from the airport at a location consistent with the airplane departing to the northeast and turning right about 180 degrees before ground impact. The operator's chief pilot reported that the pilot likely turned right after takeoff to fly direct to the navigational aid located southwest of the airport in order to escape the terrain induced turbulence (downdrafts) near the mountain range northeast of the airport. Examination of the airplane wreckage revealed damage and ground scars consistent with a high-energy, low-angle impact during a right turn. No evidence was found of preimpact mechanical malfunctions or failures that would have precluded normal operation. It is likely that the pilot became spatially disoriented during the right turn. Although visual meteorological conditions prevailed, no natural horizon and few external visual references were available during the departure. This increased the importance for the pilot to monitor the airplane's flight instruments to maintain awareness of its attitude and altitude. During the turn, the pilot was likely performing the additional task of engaging the autopilot, which was located on the center console below the throttle quadrant. The combination of conducting a turn with few visual references in gusting wind conditions while engaging the autopilot left the pilot vulnerable to visual and vestibular illusions and reduced his awareness of the airplane's attitude, altitude, and trajectory. Based on toxicology findings, the pilot most likely had symptoms of an upper respiratory infection but the investigation was unable to determine what effects these symptoms may have had on his performance. A therapeutic level of doxylamine, a sedating antihistamine, was detected, and impairment by doxylamine most likely contributed to the development of spatial disorientation.
Probable cause:
The pilot's spatial disorientation while turning during flight in dark night conditions and terrain-induced turbulence, which resulted in controlled flight into terrain. Contributing to the accident was the pilot's impairment from a sedating antihistamine.
Final Report:

Crash of a Cessna 208B Grand Caravan in Kibeni: 3 killed

Date & Time: Nov 25, 2013 at 1340 LT
Type of aircraft:
Operator:
Registration:
P2-SAH
Survivors:
Yes
Schedule:
Kamusi – Purari – Vailala – Port Moresby
MSN:
208B-1263
YOM:
2007
Location:
Region:
Crew on board:
1
Crew fatalities:
Pax on board:
9
Pax fatalities:
Other fatalities:
Total fatalities:
3
Captain / Total flying hours:
2200
Captain / Total hours on type:
800.00
Circumstances:
On 25 November 2013, a Cessna Aircraft Company C208B Grand Caravan, registered P2-SAH and operated by Tropicair, departed Kamusi, Western Province, for Purari River, Gulf Province, at 0312 UTC on a charter flight under the instrument flight rules (IFR). There were 10 persons on board; one pilot and nine passengers . Earlier in the day, the aircraft had departed Port Moresby for Kamusi from where it flew to Hivaro and back to Kamusi before the accident flight. SAH was due to continue from Purari River to Vailala and Port Moresby. The pilot reported that the takeoff and climb from Kamusi were normal and he levelled off at 9,000 ft and completed the top-of-climb checklist. Between Kamusi and Purari River the terrain is mostly flat and forest covered, with areas of swampland and slow-moving tidal rivers. Habitation is very sparse with occasional small villages along the rivers. The pilot recalled that the weather was generally good in the area with a cloud base of 3,000 ft and good visibility between build-ups. The pilot reported that approximately 2 minutes into the cruise there was a loud ‘pop’ sound followed by a complete loss of engine power. After configuring the aircraft for best glide speed at 95 kts, the pilot turned the aircraft right towards the coast and rivers to the south, and completed the Phase-1 memory recall items for engine failure in flight. He was assisted by the passenger in the right pilot seat who switched on the Emergency Locator Transmitter (ELT) and at 0332 broadcast MAYDAY due engine failure on the area frequency. Checking the database in the on-board Global Positioning System (GPS), the pilot found the airstrip at Kibeni on the eastern side of the Palbuna River. The pilot, assisted by the passenger next to him, tried unsuccessfully to restart the engine using the procedure in the aircraft’s Quick Reference Handbook (QRH). The passenger continued to give position reports and to communicate with other aircraft. At about 3,000 ft AMSL the pilot asked for radio silence on the area frequency so he could concentrate on the approach to Kibeni airstrip, flying a left hand circuit to land in a south westerly direction. He selected full flaps during the final stages of the approach, which arrested the aircraft’s rate of descent, but the higher than normal speed of the aircraft during the approach and landing flare caused it to float and touch down half way along the airstrip. The disused 430 metre long Kibeni airstrip was overgrown with grass and weeds. It was about 60 ft above the river and 120 ft above mean sea level, with trees and other vegetation on the slope down to the river. The aircraft bounced three times and, because the aircraft’s speed had not decayed sufficiently to stop in the available length, the pilot elected to pull back on the control column in order to clear the trees that were growing on the slope between the airstrip and the river. The aircraft became airborne, impacting the crown of a coconut palm (that was almost level with the airstrip) as it passed over the trees. The pilot banked the aircraft hard left in an attempt to land/ditch along the river and avoid trees on the opposite bank. He then pushed forward on the control column to avoid stalling the aircraft and levelled the wings before the aircraft impacted the water. The aircraft came to rest inverted with the cockpit and forward cabin submerged and immediately filled with water. After a short delay while he gained his bearings under water, the pilot was able to undo his harness and open the left cockpit door. He swam to the rear of the aircraft, opened the right rear cabin door, and helped the surviving passengers to safety on the river bank. He made several attempts to reach those still inside the aircraft. When he had determined there was nothing further he could do to reach them, he administered first aid to the survivors with materials from the aircraft’s first aid kit. After approximately 20 minutes, villagers arrived in a canoe and transported the pilot and surviving passengers to Kibeni village across the river. About 90 minutes after the accident, rescuers airlifted the survivors by helicopter to Kopi, located 44 km north east of Kibeni.
Probable cause:
The engine power loss was caused by the fracture of one CT blade in fatigue, which resulted in secondary damage to the remainder of the CT blades and downstream components. The fatigue originated from multiple origins on the pressure side of the blade trailing edge. The root cause for the fatigue initiation could not be determined with certainty. All other damages to the engine are considered secondary to the primary CT blades fracture.
Final Report:

Crash of a BAe 146-200 in Balesin

Date & Time: Oct 19, 2013 at 1149 LT
Type of aircraft:
Operator:
Registration:
RP-C5525
Survivors:
Yes
Schedule:
Manila - Balesin
MSN:
E2031
YOM:
1985
Location:
Country:
Region:
Crew on board:
7
Crew fatalities:
Pax on board:
68
Pax fatalities:
Other fatalities:
Total fatalities:
0
Circumstances:
The aircraft was performing a charter flight from Manila to Balesin, carrying tourists en route to the Balesin Island Club. The approach and landing were completed in poor weather conditions with heavy rain falls. After landing, the four engine aircraft was unable to stop within the remaining distance. It overran, lost its nose gear and came to rest in the Lamon Bay, few dozen metres offshore. All 75 occupants escaped uninjured while the aircraft was damaged beyond repair.

Crash of a Cessna 208B Grand Caravan in Likawage

Date & Time: Oct 11, 2013
Type of aircraft:
Operator:
Registration:
5H-KEN
Flight Phase:
Survivors:
Yes
Schedule:
Likawage – Dar es Salaam
MSN:
208B-0384
YOM:
1994
Country:
Region:
Crew on board:
2
Crew fatalities:
Pax on board:
1
Pax fatalities:
Other fatalities:
Total fatalities:
0
Circumstances:
The single engine aircraft was engaged in a charter flight from Likawage to Dar es Salaam, carrying one passenger and two pilots. Ready for takeoff at threshold, the crew applied full power and maintained brakes. Despite the engine did not reach the takeoff power, the captain released brakes and initiated the takeoff roll. The aircraft rolled for about three-quarters of the runway when the engine reached the takeoff power. But the aircraft failed to rotate, continued, overran and eventually collided with trees, bursting into flames. All three occupants were slightly injured and the aircraft was partially destroyed by fire.

Crash of an Embraer EMB-120ER Brasília in Lagos: 16 killed

Date & Time: Oct 3, 2013 at 0932 LT
Type of aircraft:
Operator:
Registration:
5N-BJY
Flight Phase:
Survivors:
Yes
Schedule:
Lagos - Akure
MSN:
120-174
YOM:
1990
Flight number:
SCD361
Country:
Region:
Crew on board:
7
Crew fatalities:
Pax on board:
13
Pax fatalities:
Other fatalities:
Total fatalities:
16
Captain / Total flying hours:
20068
Captain / Total hours on type:
1309.00
Copilot / Total flying hours:
4660
Copilot / Total hours on type:
3207
Aircraft flight hours:
27362
Aircraft flight cycles:
34609
Circumstances:
The crew discussed some concerns about the aircraft prior to departure but at this time we are not prepared to elaborate on those concerns as there remains a lot of work to complete on the CVR analysis in order to determine the specific nature of the crew’s concerns. Associated 361 was cleared for take-off on runway one eight left at Lagos international airport. The wind was calm and weather is not considered a factor in this accident. Approximately 4 seconds after engine power was advanced to commence the take-off roll, the crew received an automated warning from the onboard computer voice which consisted of three chimes followed by “Take-off Flaps…Take-off Flaps”. This is a configuration warning that suggests that the flaps were not in the correct position for take-off and there is some evidence that the crew may have chosen not to use flaps for the take-off. The warning did not appear to come as any surprise to the crew and they continued normally with the take-off. This warning continues throughout the take-off roll. As we are in the process of verifying the accuracy of the flight data, we have not yet been able to confirm the actual flap setting however we expect to determine this in the fullness of time. It was determined from the CVR that the pilot flying was the Captain and the pilot monitoring and assisting was the First Officer. The ‘set power‘ call was made by the Captain and the ‘power is set’ call was confirmed by the First Officer as expected in normal operations. Approximately 3 seconds after the ‘power is set’ call, the First Officer noted that the aircraft was moving slowly. Approximately 7 seconds after the ‘power is set’ call, the internal Aircraft Voice warning system could be heard stating ‘Take off Flaps, Auto Feather’. Auto feather refers to the pitch of the propeller blades. In the feather position, the propeller does not produce any thrust. The FDR contains several engine related parameters which the AIB is studying. At this time, we can state that the Right engine appears to be producing considerably less thrust than the Left engine. The left engine appeared to be working normally. The aircraft automated voice continued to repeat ‘Take-off Flaps, Auto Feather’. The physical examination of the wreckage revealed that the right engine propeller was in the feather position and the engine fire handle was pulled/activated. The standard ‘eighty knots’ call was made by the First Officer. The first evidence that the crew indicated that there was a problem with the take-off roll was immediately following the ‘eighty knots’ call. The First Officer asked if the take- off should be aborted approximately 12 seconds after the ‘eighty knots’ callout. Our investigation team estimates the airspeed to be approximately 95 knots. Airspeed was one of the parameters that, while working in the cockpit, appeared not to be working on the Flight Data Recorder. We were able to estimate the speed based on the radar data that we synchronized to the FDR and CVR but it is very approximate because of this. In response to the First Officer’s question to abort, the Captain indicated that they should continue and they continued the take-off roll. The crew did not make a ‘V1’ call or a Vr’ call. V1 is the speed at which a decision to abort or continue a take-off is made. Vr is the speed at which it is planned to rotate the aircraft. Normally the non-flying pilot calls both the V1 and the Vr speeds. When Vr is called the flying pilot pulls back on the control column and the aircraft is rotated (pitched up) to climb away from the runway. During the rotation, the First Officer stated ‘gently’, which we believe reflects concern that the aircraft is not performing normally and therefore needs to be rotated very gently so as not to aerodynamically stall the aircraft. The First Officer indicated that the aircraft was not climbing and advised the Captain who was flying not to stall the aircraft. Higher climb angles can cause an aerodynamic stall. If the aircraft is not producing enough overall thrust, it is difficult or impossible to climb without the risk of an aerodynamic stall. Immediately after lift-off, the aircraft slowly veered off the runway heading to the right and was not climbing properly. This aircraft behavior appears to have resulted in the Air Traffic Controller asking Flight 361 if operation was normal. Flight 361 never responded. Less than 10 seconds after rotation of the aircraft to climb away from the runway, the stall warning sounded in the cockpit and continued to the end of the recording. The flight data shows characteristics consistent with an aerodynamic stall. 31 seconds after the stall warning was heard, the aircraft impacted the ground in a nose down near 90° right bank.
Probable cause:
The accident was the consequence of the decision of the crew to continue the take-off despite the abnormal No. 2 Propeller rpm indication and a low altitude stall as a result of low thrust at start of roll for take-off from No. 2 Engine caused by an undetermined malfunction of the propeller control unit.
The following contributing factors were identified:
- The aircraft was rotated before attaining V1.
- The decision to continue the take-off with flap configuration warning and auto- feather warning at low speed.
- Poor professional conduct of the flight crew.
- Inadequate application of Crew Resource Management (CRM) principles.
- Poor company culture.
- Inadequate regulatory oversight.
Final Report:

Crash of a Beechcraft C90A King Air in Idaho Falls

Date & Time: Sep 19, 2013 at 1553 LT
Type of aircraft:
Operator:
Registration:
N191TP
Survivors:
Yes
Schedule:
Pocatello – Idaho Falls
MSN:
LJ-1223
YOM:
1989
Crew on board:
1
Crew fatalities:
Pax on board:
2
Pax fatalities:
Other fatalities:
Total fatalities:
0
Captain / Total flying hours:
3975
Captain / Total hours on type:
2500.00
Aircraft flight hours:
4468
Circumstances:
The airplane was equipped with two main fuel tanks (132 usable gallons each) and two nacelle fuel tanks (60 usable gallons each). In normal operation, fuel from each nacelle tank is supplied to its respective engine, and fuel is automatically transferred from each main tank to its respective nacelle tank. While at the airplane's home airport, the pilot noted that the cockpit fuel quantity gauges indicated that the nacelle tanks were full, and he believed that the main tanks had fuel sufficient for 30 minutes of flight. The pilot did not verify by any other means the actual fuel quantity in any of the tanks. Thirty gallons of fuel were added to each main tank; they were not topped off. The airplane, with two passengers, then flew to an interim stop about 45 miles away, where a third passenger boarded. The airplane then flew to its destination, another 165 miles away. The pilot reported that, at the destination airport, he noted that the cockpit fuel quantity gauges indicated that the nacelle tanks were full; he surmised that the main fuel tanks were not empty but did not note the actual quantity of fuel. Forty gallons of fuel were added to each main tank. Again, the main tanks were not topped off, and the pilot did not verify by any other means the actual fuel quantity in any of the tanks. The return flight to the interim stop was uneventful. The third passenger deplaned there, and the airplane departed for its home airport. While on final approach to the home airport, both engines stopped developing power, and the pilot conducted a forced landing to a field about 1.2 miles short of the runway. The pilot later reported that, at the time of the power loss, the fuel quantity gauges indicated that there was still fuel remaining in the airplane. Postaccident examination of the airplane revealed that all four fuel tanks were devoid of fuel. The examination did not reveal any preimpact mechanical anomalies, including fuel leaks, that would have precluded continued flight. The airplane manufacturer conducted fuel-consumption calculations for each of the two city pairs. Because the pilot did not provide any information regarding flight routes, altitudes, speeds, or times for any of the flight segments, the manufacturer's calculations were based on direct routing in zero-wind conditions, nominal airplane and engine performance, and assumed cruise altitudes and speeds. Although the results are valid for these input parameters, variations in any of the input parameters can significantly affect the calculated fuel requirements. As a result, although the manufacturer's calculations indicated that the round trip would have burned less fuel than the total available fuel quantity that was derived from the pilot-provided information, the lack of any definitive information regarding the actual flight parameters limited the utility of the calculated value and the comparison. The manufacturer's calculations indicated that the accident flight leg (from the interim airport to the home airport) would have consumed about 28.5 gallons total. Given that the airplane was devoid of fuel at the accident site, the pilot likely departed the interim airport with significantly less than the manufacturer's minimum allowable departure fuel quantity of about 39.5 gallons per side. The lack of any observed preimpact mechanical problems with the airplane, combined with the lack of objective or independently substantiated fuel quantity information, indicates that the airplane's fuel exhaustion was due to the pilot's inadequate and improper pre- and inflight fuel planning and procedures.
Probable cause:
The pilot's inadequate preflight fuel planning, which resulted in departure with insufficient fuel to complete the flight, and consequent inflight power loss due to fuel exhaustion.
Final Report:

Crash of a PZL-Mielec AN-2R near Nyagan

Date & Time: Sep 18, 2013 at 1337 LT
Type of aircraft:
Operator:
Registration:
RA-33017
Flight Phase:
Survivors:
Yes
Schedule:
Surgut – Saranpaul – Arbyn – Surgut
MSN:
1G218-04
YOM:
1986
Country:
Region:
Crew on board:
2
Crew fatalities:
Pax on board:
5
Pax fatalities:
Other fatalities:
Total fatalities:
0
Aircraft flight hours:
5277
Aircraft flight cycles:
24822
Circumstances:
The aircraft departed Surgut on September 12 on a special flight to Saranpaul and Arbyn, carrying two pilots and five employees of the Sosvapromgeologya Company. On September 18, the crew was supposed to fly back to Surgut but due to poor weather conditions, decided to fly to Nefteyugansk. About an hour and 10 minutes into the flight, while cruising at an altitude of 700 metres, the engine temperature increased to 305° C. and the oil temperature to 90° C. In the same time, the engine lost power. The crew decided to reduce his altitude and to attempt an emergency landing when the aircraft crash landed in a field located 48 km west of Nyagan. There was no fire. All seven occupants were injured and the aircraft was damaged beyond repair.
Probable cause:
Most probably the accident with An-2 RA-33017 aircraft was caused by usage of uncoordinated automative fuel not specified by valid aircraft maintenance engineering documentation with low octane grade, mechanical admixture (rusting) that resulted in cylinder-heads temperature increase beyond operating limits, engine power loss, unintentional flight altitude decrease and the need of an emergency landing on saturated terrain.
The contributing factors could be:
- Unsatisfactory management of storage, refiling procedures and fuel quality inspection at Arbyn Airfield,
- Incorrect PIC's decision to perform a flight after detection of deviation from standards in fuel quick drain (color, consistency, mechanical mixtures).