Crash of a Cessna S550 Citation II in Indianapolis: 2 killed

Date & Time: May 22, 2019 at 1243 LT
Type of aircraft:
Operator:
Registration:
N311G
Flight Phase:
Flight Type:
Survivors:
No
Schedule:
Indianapolis - Minden
MSN:
550-0041
YOM:
1985
Crew on board:
1
Crew fatalities:
Pax on board:
1
Pax fatalities:
Other fatalities:
Total fatalities:
2
Captain / Total flying hours:
3530
Circumstances:
The pilot was conducting a personal cross-country flight in a turbofan-powered airplane. Shortly after departure, the airplane entered a witness-estimated 90° left bank with the nose parallel to the horizon; as the airplane began to roll out of the turn, the nose remained at or below the horizon before it dropped and the airplane impacted the ground. Flight track data revealed that, shortly after departure, the airplane's ground speed immediately began decreasing from its maximum of 141 knots during takeoff and continued decreasing until the last recorded data point, which showed that the airplane had a ground speed of 100 knots. The surface wind reported about 10 minutes before the accident was from 170° at 9 knots, gusting to 14 knots, which resulted in a 1- to 2-knot tailwind component. Given this information and the airplane's configuration at the time of the accident, the airplane's indicated airspeed (IAS) would have been between about 86 and 93 knots. The airplane's stall speed was calculated to be 100 knots IAS (KIAS) with a bank angle of 45° and 118 KIAS with a bank angle of 60°. Thus, the pilot failed to maintain airspeed or accelerate after departure, which resulted in an aerodynamic stall A pilot who had flown with the accident pilot twice before the accident reported that, during these flights, the pilot had flown at reduced power settings and slower-than-normal airspeeds. During the flight 1 year before the accident, he reached over and pushed the power levers forward himself. He also stated that every time he had flown with the pilot, he was "very behind the airplane." Postaccident examination of the engines revealed no signs of preimpact mechanical failures or malfunctions that would have precluded normal operation, and both engines exhibited circumferential rub marks on all rotating stages, blade tip bending opposite the direction of rotation, and debris ingestion through the gas path, indicating that the engine had power at impact. Further, the right engine full authority digital electronic control (FADEC) nonvolatile memory recorded no faults. (The left engine FADEC could not be downloaded due to damage.) The Airplane Flight Manual stated that the pilot must, in part, advance the throttle lever to the maximum takeoff detent for the FADEC's nonvolatile memory to record a logic trend snapshot 2 seconds after takeoff. The lack of a FADEC logic trend snapshot is consistent with the pilot not fully advancing the throttles during the takeoff and initial climb and is likely why he did not attain or maintain sufficient airspeed. The flight track data, pilot witness account, and airplane damage are consistent with the pilot failing to fully advance the power levers while maneuvering shortly after takeoff, which led to his failure to maintain sufficient airspeed and resulted in the exceedance of the airplane's critical angle of attack and a subsequent aerodynamic stall.
Probable cause:
The pilot's failure to fully advance the power levers during the takeoff and initial climb, which led to his failure to maintain sufficient airspeed and resulted in the exceedance of the airplane's critical angle of attack and a subsequent aerodynamic stall.
Final Report:

Crash of a Beechcraft 60 Duke in Loveland: 1 killed

Date & Time: May 15, 2019 at 1248 LT
Type of aircraft:
Operator:
Registration:
N60RK
Flight Type:
Survivors:
No
Schedule:
Broomfield – Loveland
MSN:
P-79
YOM:
1969
Crew on board:
1
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
1
Captain / Total flying hours:
7000
Captain / Total hours on type:
100.00
Aircraft flight hours:
3119
Circumstances:
The commercial pilot was relocating the multiengine airplane following the completion of an extensive avionics upgrade, which also included the installation of new fuel flow transducers. As the pilot neared the destination airport, he reported over the common traffic advisory frequency that he had "an engine out [and] smoke in the cockpit." Witnesses observed and airport surveillance video showed fire emanating from the airplane's right wing. As the airplane turned towards the runway, it entered a rightrolling descent and impacted the ground near the airport's perimeter fence. The right propeller was found feathered. Examination of the right engine revealed evidence of a fire aft of the engine-driven fuel pump. The fuel pump was discolored by the fire. The fire sleeves on both the fuel pump inlet and outlet hoses were burned away. The fuel outlet hose from the fuel pump to the flow transducer was found loose. The reason the hose was loose was not determined. It is likely that pressurized fuel sprayed from the fuel pump outlet hose and was ignited by the hot turbocharger, which resulted in the inflight fire.
Probable cause:
A loss of control due to an inflight right engine fire due to the loose fuel hose between the engine-driven fuel pump and the flow transducer.
Final Report:

Crash of a De Havilland Dash-8-Q402 in Yangon

Date & Time: May 8, 2019 at 1852 LT
Operator:
Registration:
S2-AGQ
Survivors:
Yes
Schedule:
Dhaka - Yangon
MSN:
4367
YOM:
2011
Flight number:
BG060
Country:
Region:
Crew on board:
6
Crew fatalities:
Pax on board:
28
Pax fatalities:
Other fatalities:
Total fatalities:
0
Captain / Total flying hours:
9646
Captain / Total hours on type:
1474.00
Copilot / Total flying hours:
580
Copilot / Total hours on type:
405
Aircraft flight hours:
8115
Circumstances:
The route of the aircraft on that day was DAC-RGN-DAC. At (18:03) the Bombardier DHC-8-402 aircraft, registered (S2-AGQ) contacted Yangon control tower and at (18:16) had ILS established and reported to the Yangon control tower. Due to adverse weather, Yangon control tower asked them to execute a go-around and the aerodrome operations was closed for the aviation safety for 2 hours. When the weather condition got better, the aerodrome operations was opened. And then the DHC-8-402 aircraft, registered S2-AGQ made RNP approach because only localizer was available at that moment. While the Bombardier DHC-8-402 aircraft was and making approach to runway 21, it was a bit higher than on slope 3 degree and landed on runway 21, remaining on the ground for upwards of 7 seconds, but the aircraft ran parallel to the runway, and then it flew up in the air up to 44 ft above the ground and sank again and collided with runway 03 and slid forward out of the runway and came to a complete stop on the over-run of the runway 03. There was no fire. All gears were collapsed and fuselage was broken into three sections. All 33 occupants were evacuated, among them 20 were injured. The aircraft was destroyed.
Probable cause:
While the aircraft was unstabilized on approach, the pilot did not execute a go-around.
Final Report:

Crash of a Sukhoi Superjet 100-95B in Moscow: 41 killed

Date & Time: May 5, 2019 at 1830 LT
Type of aircraft:
Operator:
Registration:
RA-89098
Survivors:
Yes
Schedule:
Moscow - Murmansk
MSN:
95135
YOM:
2017
Flight number:
SU1492
Country:
Region:
Crew on board:
5
Crew fatalities:
Pax on board:
73
Pax fatalities:
Other fatalities:
Total fatalities:
41
Captain / Total flying hours:
6800
Captain / Total hours on type:
1570.00
Copilot / Total flying hours:
765
Copilot / Total hours on type:
615
Aircraft flight hours:
2710
Aircraft flight cycles:
1658
Circumstances:
The aircraft departed runway 24C at Moscow-Sheremetyevo Airport at 1803LT on a schedule service to Murmansk. Few minutes after takeoff, while climbing to an altitude of 10,000 feet, the crew encountered problems with the electrical system and informed ATC about an emergency situation via the transponder codes 7700 because communication systems were unserviceable. The crew initiated a circuit to return to the airport, continued the approach to runway 24L. On approach at an altitude between 900 and 1,100 feet, the windshear warning system sounded five times 'Go around. Windshear ahead'. From a height of 80 m (260 ft) above ground level, the aircraft descended below the glide path and at a height of 55 m (180 ft) the TAWS warning sounded: "Glide Slope." From that moment on the airspeed increased to 170 knots. At 18:30 the aircraft overflew the runway threshold and touched down at a distance of 900 m past the threshold at a speed of 158 knots. Touchdown occurred at a g-force of at least 2.55g with a subsequent bounce to a height of about 2 m. After two seconds the aircraft landed again on the nose landing gear with a vertical load 5.85g, and bounced to a height of 6 m. The third landing of the aircraft occurred at a speed of 140 knots with a vertical overload of at least 5g. This caused a rupture of the wing structure and fuel lines. The aircraft caught fire, went out of control, veered off runway to the right and came to rest in a grassy area, bursting into flames. The aircraft was destroyed by fire. 37 occupants were evacuated while 41 people, among them a crew member, were killed.

Crash of a Beechcraft A60 Duke in Santa Rosa: 2 killed

Date & Time: May 5, 2019 at 1600 LT
Type of aircraft:
Operator:
Registration:
N102SN
Flight Type:
Survivors:
No
Schedule:
Arlington - Santa Fe
MSN:
P-217
YOM:
1973
Crew on board:
1
Crew fatalities:
Pax on board:
1
Pax fatalities:
Other fatalities:
Total fatalities:
2
Captain / Total flying hours:
4100
Circumstances:
The pilot was performing a personal cross-country flight. While en route to the intended destination, the pilot contacted air traffic control to report that the airplane was having a fuel pump issue and requested to divert to the nearest airport. The pilot stated that the request was only precautionary and did not declare an emergency during the flight; he provided no further information about the fuel pump. As the airplane approached the diversion airport, witnesses observed the airplane flying low and rolling to the left just before impacting terrain, after which a postcrash fire ensued. An examination of the airframe revealed no preimpact mechanical malfunctions or failures that would have precluded normal operation. A postaccident examination and review of recorded data indicated that the left engine was secured and in the feather position, and that the right engine was operating at a high RPM setting. The left engine-driven fuel pump was found fractured. Further examination of the fuel pump revealed fatigue failure of the pressure relief valve. The fatigue failure initiated in upward bending on one side of the valve disk and progressed around both sides of the valve stem. As the cracks grew, the stem separated from the disk on one side and began to tilt in relation to the disk and the valve guide due to the non-symmetric support, which caused the lower end of the stem to rub against the valve guide, creating wear marks. The increasing stem tilt would have impinged against the valve guide, and the valve might have begun to stick in the closed position. If the valve were stuck in the closed position, it would not be able to open, and the outlet fuel pressure could rise above the set point pressure. Because the pump was driven by the engine, there would not be a way for the pilot to shut it off, disconnect it, or bypass it. Instead, the fuel pressure would continue to rise until the valve were to unstick. Thus, the pilot was likely experiencing variable fuel pressure as the valve became stuck and unstuck. Examination of the spring seat and the diaphragm plate, which were in contact with each other in the fuel pump assembly, revealed wear marks on the surface of each component, with one mark on the diaphragm plate and two wear marks on the spring seat. The two wear marks on the spring seat were distinct features separated by material with no wear indications in between. The only way that these wear marks could have occurred were if the spring seat was separated from the diaphragm plate and reinstalled in a different orientation. Thus, it is likely that the pilot had encountered a fuel pump problem before the accident flight and that someone tried to troubleshoot the problem. The last radar data point indicated that the airplane was traveling at a groundspeed of about 98 knots, and had passed north of the airport, traveling to the southwest. The minimum control speed for the airplane with single-engine operation was 88 knots. However, it is likely that if the pilot initiated a left turn back toward the airport, that the right engine torque and the 14 knot wind with gusts to 24 knots would have necessitated a higher speed. Because appropriate control inputs and airspeed were not maintained, the airplane rolled in the direction of the feathered engine (due to the left fuel pump problem), resulting in a loss of control. The pilot's toxicology report was positive for cetirizine, sumatriptan, gabapentin, topiramate, and duloxetine. All of these drugs act in the central nervous system and can be impairing alone or in combination. Although this investigation could not determine the reason(s) for the pilot's use of these drugs, they are commonly used to treat chronic pain syndromes or seizures. It is likely that the pilot was experiencing some impairment because of multiple impairing medications and was unable to successfully respond to the in-flight urgent situation and safely land the airplane.
Probable cause:
The pilot's loss of airplane control due to his failure to maintain appropriate control inputs and airspeed after shutting down an engine because of a progressive failure of the pressure relief valve in the fuel pump, which resulted in variable fuel pressure in the engine. Contributing to the loss of control was the pilot's use of multiple impairing medications.
Final Report:

Crash of a PZL-Mielec AN-2R in Vyun

Date & Time: May 4, 2019 at 1335 LT
Type of aircraft:
Registration:
RA-01443
Flight Type:
Survivors:
Yes
Schedule:
Ust-Nera - Vyun
MSN:
1G231-24
YOM:
1988
Country:
Region:
Crew on board:
2
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
0
Captain / Total flying hours:
9700
Aircraft flight hours:
6305
Circumstances:
The single engine airplane departed Ust-Nera on a cargo flight to Vyun, carrying two pilots and a load of various equipment destined for the employees of a local gold mine. Upon landing on an unprepared terrain, the undercarriage collapsed. The airplane slid on its belly and came to rest. Both pilots escaped uninjured and the aircraft was damaged beyond repair. The accident occurred at location N 65° 54' E 138° 20'.
Probable cause:
The accident was the result of the destruction of the right main landing gear strut upon landing.
The following contributing factors were identified:
- Unsatisfactory performance of the welded joint in the manufacture of the strut with the formation of welding cracks in one of the most stressed zones of the strut,
- Pilot errors, which led to an early landing of the aircraft, possibly rough, on an unprepared (uncleared) area with possible obstacles.
Final Report:

Crash of a Beechcraft B200 Super King Air in Gillam

Date & Time: Apr 24, 2019 at 1823 LT
Operator:
Registration:
C-FRMV
Flight Type:
Survivors:
Yes
Schedule:
Winnipeg – Churchill – Rankin Inlet
MSN:
BB-979
YOM:
1982
Flight number:
KEW202
Location:
Country:
Crew on board:
2
Crew fatalities:
Pax on board:
2
Pax fatalities:
Other fatalities:
Total fatalities:
0
Captain / Total flying hours:
1350
Captain / Total hours on type:
1100.00
Copilot / Total flying hours:
3500
Copilot / Total hours on type:
1350
Circumstances:
On 24 April 2019, the Keewatin Air LP Beechcraft B200 aircraft (registration C‑FRMV, serial number BB979), equipped to perform medical evacuation flights, was conducting an instrument flight rules positioning flight (flight KEW202), with 2 flight crew members and 2 flight nurses on board, from Winnipeg/James Armstrong Richardson International Airport, Manitoba, to Rankin Inlet Airport, Nunavut, with a stop at Churchill Airport, Manitoba. At 1814 Central Daylight Time, when the aircraft was cruising at flight level 250, the flight crew declared an emergency due to a fuel issue. The flight crew diverted to Gillam Airport, Manitoba, and initiated an emergency descent. During the descent, both engines flamed out. The flight crew attempted a forced landing on Runway 23, but the aircraft touched down on the frozen surface of Stephens Lake, 750 feet before the threshold of Runway 23. The landing gear was fully extended. The aircraft struck the rocky lake shore and travelled up the bank toward the runway area. It came to rest 190 feet before the threshold of Runway 23 at 1823:45 Central Daylight Time. None of the occupants was injured. The aircraft sustained substantial damage. The 406 MHz emergency locator transmitter activated. Emergency services responded. There was no fire.
Probable cause:
Findings as to causes and contributing factors:
These are conditions, acts or safety deficiencies that were found to have caused or contributed to this occurrence.
1. When the captain asked if the aircraft was ready for the flight, the first officer replied that it was, not recalling that the aircraft required fuel.
2. While performing the FUEL QUANTITY item on the AFTER START checklist, the captain responded to the first officer’s prompt with the rote response that the fuel was sufficient, without looking at the fuel gauges.
3. The aircraft departed Winnipeg/James Armstrong Richardson International Airport with insufficient fuel on board to complete the planned flight.
4. The flight crew did not detect that there was insufficient fuel because the gauges had not been included in the periodic cockpit scans.
5. When the flight crew performed the progressive fuel calculation, they did not confirm the results against the fuel gauges, and therefore their attention was not drawn to the low-fuel state at a point that would have allowed for a safe landing.
6. Still feeling the effect of the startle response to the fuel emergency, the captain quickly became task saturated, which led to an uncoordinated response by the flight crew, delaying the turn toward Gillam Airport, and extending the approach.
7. The right engine lost power due to fuel exhaustion when the aircraft was 1 nautical mile from Runway 23. From that position, a successful forced landing on the intended runway was no longer possible and, as a result, the aircraft touched down on the ice surface of Stephens Lake, short of the runway.

Findings as to risk:
These are conditions, unsafe acts or safety deficiencies that were found not to be a factor in this occurrence but could have adverse consequences in future occurrences.
1. If procedures are not developed to instruct pilots on their roles and responsibilities during line indoctrination flights, there is a risk that flight crew members may not participate when expected, or may work independently towards different goals.

Other findings:
These items could enhance safety, resolve an issue of controversy, or provide a data point for future safety studies.
1. Because emergency medical services and the fire department were not notified immediately about the declared emergency, they were not on site before the aircraft arrived at Gillam Airport.
Final Report:

Crash of a Cessna 551 Citation II/SP in Siegerland

Date & Time: Apr 24, 2019 at 1442 LT
Type of aircraft:
Operator:
Registration:
D-IADV
Flight Type:
Survivors:
Yes
Schedule:
Siegerland - Siegerland
MSN:
551-0552
YOM:
1987
Country:
Region:
Crew on board:
2
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
0
Captain / Total flying hours:
6800
Captain / Total hours on type:
170.00
Copilot / Total flying hours:
1300
Copilot / Total hours on type:
0
Aircraft flight hours:
8479
Aircraft flight cycles:
7661
Circumstances:
The Cessna 551 Citation II/SP corporate jet took off at 13:30 local time from Reichelsheim Airfield, Germany, for a training flight at Siegerland Airport. It was a training flight to acquire the type rating for the aircraft. The right pilot's seat was occupied by the pilot in command, who was deployed on this flight as a flight instructor. The student pilot, as co-pilot, sat on the left pilot seat and was the pilot flying. For the co-pilot it was the second flight day of his practical training program on the Cessna 551 Citation II/SP. The day before, he had already completed about three flying hours on the plane. At Siegerland Airport, three precision approaches to runway 31 were carried out with the help of the Instrument Landing System (ILS). After the third landing, the tower, due to the changed wind, turned the landing direction to runway 13. The cockpit crew therefore rolled the aircraft to the end of the runway, turned and took off at 14:34 from runway 13. This was followed by a left-hand circuit at an altitude of 3,500 ft AMSL. The approach to runway 13 took place under visual flight conditions. According to both pilots, the checklists were processed during the circuit and the aircraft was prepared for landing on runway 13. In the final approach, the landing configuration was then established and the landing checklist performed. The copilot reported that shortly before the landing the speed decreased, the aircraft flew too low and the approach angle had to be corrected. He pushed the engine thrust levers forward to the stop. The pilot in command supported this action by also pushing the engine thrust levers forward with his hand. However, according to the pilot in command, the remaining time to touch down on the runway was no longer sufficient for the engines to accelerate to maximum speed in order to deliver the corresponding thrust. He also described that the aircraft had been in the stall area at that time. However, he had not noticed a stall warning. At 14:42, with the landing gear extended, the aircraft touched down in the grass in front of the asphalt area of runway 13. The left main landing gear buckled and damaged the tank of the left wing. The right main landing gear also buckled, the tank on the right side remained undamaged. The kerosene escaping from the left wing ignited and a fire broke out. The aircraft burned and slipped along runway 13 on the folded landing gear, the underside of the airframe and the extended landing flaps until it came to a standstill after a distance of approx. 730 m from runway threshold 13. After the plane had come to a standstill on the runway, the copilot noticed flames on the left side of the plane. The pilot switched off both engines. Then both pilots left the plane via the emergency exit door on the right side. The pilots were not injured.
Probable cause:
The accident, during which the airplane touched down ahead of the runway, was caused by an unstabilized approach and the non-initiation of a go-around procedure.
The following factors contributed to the accident:
- The organisation of the traffic pattern was performed too close to the airport.
- The final approach was flown too short and conducted in a way that it resulted in an unstabilized approach.
- During the final approach the approach angle was not correctly maintained until the runway threshold.
- During the final approach speed was too low.
- Both pilots did not recognize the decrease in speed early enough and had not increased engine performance in time.
- The flight instructor intervened too late and thus control of the flight attitude of the aircraft was not regained soon enough.
- The ascending terrain ahead of the runway threshold was also a contributory factor. It is highly likely that the student pilot had the impression of being too high and deliberately maintained a shallow approach angle.
Final Report:

Crash of a Beechcraft B60 Duke in Fullerton: 1 killed

Date & Time: Apr 18, 2019 at 1951 LT
Type of aircraft:
Registration:
N65MY
Flight Phase:
Flight Type:
Survivors:
No
Schedule:
Fullerton - Heber City
MSN:
P-314
YOM:
1975
Crew on board:
1
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
1
Captain / Total flying hours:
380
Captain / Total hours on type:
87.00
Aircraft flight hours:
5419
Circumstances:
The pilot began the takeoff roll in visual meteorological conditions. The airplane was airborne about 1,300 ft down the runway, which was about 75% of the normal ground roll distance for the airplane’s weight and the takeoff environment. About 2 seconds after rotation, the airplane rolled left. Three seconds later, the airplane had reached an altitude of about 80 ft above ground level and was in a 90° left bank. The nose then dropped as the airplane rolled inverted and struck the ground in a right-wing-low, nose-down attitude. The airplane was destroyed. Postaccident examination did not reveal any anomalies with the airframe or engines that would have precluded normal operation. The landing gear, flap, and trim positions were appropriate for takeoff and flight control continuity was confirmed. The symmetry of damage between both propeller assemblies indicated that both engines were producing equal and high amounts of power at impact. The autopsy revealed no natural disease was present that could pose a significant hazard to flight safety. Review of surveillance video footage from before the accident revealed that the elevator was in the almost full nose-up (or trailing edge up) position during the taxi and the beginning of the takeoff roll. Surveillance footage also showed that the pilot did not perform a preflight inspection of the airplane or control check before the accident flight. According to the pilot’s friend who was also in the hangar, as the accident pilot was pushing the airplane back into his hangar on the night before the accident, he manipulated and locked the elevator in the trailing edge up position to clear an obstacle in the hangar. However, no evidence of an installed elevator control lock was found in the cabin after the accident. The loss of control during takeoff was likely due to the pilot’s use of an unapproved elevator control lock device. Despite video evidence of the elevator locked in the trailing edge up position before the accident, an examination revealed no evidence of an installed control lock in the cabin. Therefore, during the night before the accident, the pilot likely placed an unapproved object between the elevator balance weight and the trailing edge of the horizontal stabilizer to lock the elevator in the trailing edge up position. The loss of control was also due to the pilot’s failure to correctly position the elevator before takeoff. The pilot’s friend at the hangar also reported that the pilot was running about one hour late; the night before, he was trying to troubleshoot an electrical issue in the airplane that caused a circuit breaker to keep tripping, which may have become a distraction to the pilot. The pilot had the opportunity to detect his error in not freeing the elevator both before boarding the airplane and again while in the airplane, either via a control check or detecting an anomalous aft position of the yoke. The pilot directed his attention to the arrival of a motorbike in the hangar alley shortly after he pulled the airplane out of the hangar, which likely distracted the pilot and further delayed his departure. He did not conduct a preflight inspection of the airplane or control check before the accident flight, due either to distraction or time pressure.
Probable cause:
The pilot’s use of an unapproved elevator control lock device, and his failure to remove that device and correctly position the elevator before flight, which resulted in a loss of control during takeoff. Contributing to the accident was his failure to perform a preflight inspection and control check, likely in part because of distractions before boarding and his late departure time.
Final Report:

Crash of a Let L-410UVP-E20 in Lukla: 3 killed

Date & Time: Apr 14, 2019 at 0907 LT
Type of aircraft:
Operator:
Registration:
9N-AMH
Flight Phase:
Flight Type:
Survivors:
Yes
Schedule:
Lukla - Manthali
MSN:
13 29 14
YOM:
2013
Flight number:
GO802D
Country:
Region:
Crew on board:
3
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
3
Captain / Total flying hours:
15652
Captain / Total hours on type:
3558.00
Copilot / Total flying hours:
865
Copilot / Total hours on type:
636
Aircraft flight hours:
4426
Aircraft flight cycles:
5464
Circumstances:
On 14 April 2019, around 0322Hrs, Aircraft Industries' L410UPV-E20, registration 9NAMH, owned and operated by Summit Air Pvt. Ltd. met with an accident at Tenzing-Hillary Airport, Lukla when it veered right and excurred the runway during take-off roll from runway 24. The aircraft first collided with Manang Air's helicopter, AS350B3e, registration 9N-ALC, with its rotor blade running on idle power and then with Shree Airlines' helicopter, AS350B3e, registration 9N-ALK just outside the inner perimeter fence of the aerodrome into the helipad before coming to a stop. The PIC and Cabin Crew of 9N-AMH survived the accident, whereas the Co-pilot and one security personnel on ground were killed on the spot. One more security personnel succumbed to injury later in hospital during the course of treatment. 9N-AMH and 9N-ALC both were substantially damaged by impact forces. There was no post-crash fire. Prior to the accident the aircraft had completed 3 flights on Ramechhap-Lukla-Ramechhap sector. According to PIC, he was in the left seat as the pilot monitoring (PM) and the co-pilot, in the right seat was the pilot flying (PF). According to CCTV footages, the aircraft arrived at the apron from VNRC to VNLK at 0315Hrs and shut its LH engine. The PIC started the LH engine at about 0318 Hrs after unloading cargo and passengers. At 0322:30 Hrs, the PIC aligned the aircraft with the runway at the runway threshold 24 and then handed over the controls to the co-pilot for the take-off roll. The take-off roll commenced at 0322:50 Hrs. CCTV footage captured that within 3 seconds the aircraft veered right and made an excursion. The aircraft exited the runway and travelled about 42.8 ft across the grassy part on right side of runway 24, before striking the airport inner perimeter fence. It then continued to skid for about 43 ft, into the upper helipad, crashing into 9N-ALC. Eye witnesses statements, CCTV footages and initial examination of the wreckage showed that rotor blades of helicopter 9N-ALC were on idle when RH wing of the aircraft swept two security personnel (on ground) before slashing its rotor shaft. The moving rotors cut through the cockpit on the right side slaying the Co-pilot immediately. The helicopter toppled onto the lower helipad 6 ft below. The LH wing of the aircraft broke the skid of helicopter 9NALK and came to a halt with toppled 9N-ALC beneath its RH main wheel assembly. Due to 2impact, 9N-ALK shifted about 8 ft laterally and suffered minor damages. There was no post-crash fire. The PIC switched off the battery and came out of the aircraft through emergency exit along with the cabin crew. The captain of the helicopter 9N-ALC was rescued immediately. 9N-ALC's crew sustained a broken tail-bone whereas 9N-ALK's crew escaped without sustaining major injuries. All three deceased were Nepalese citizens. Aircraft 9N-AMH and helicopter 9N-ALC were substantially damaged while the helicopter 9N-ALK endured partial damages.
Probable cause:
The commission concluded that the probable cause of the accident was aircraft's veering towards right during initial take-off roll as a result of asymmetric power due to abrupt shifting of right power lever rearwards and failure to abort the takeoff by crew. There were not enough evidences to determine the exact reason for abrupt shifting of the power lever.
Contributing Factors:
1. Failure of the PF(being a less experienced co-pilot) to immediately assess and act upon the abrupt shifting of the right power lever resulted in aircraft veering to the right causing certain time lapse for PIC to take controls in order to initiate correction.
2. PIC's attempted corrections of adding power could not correct the veering. Subsequently, application of brakes resulted in asymmetric braking due to the position of the pedals, and further contributed veering towards right.
Final Report: