Crash of a De Havilland DHC-2 Beaver off Metlakatla: 2 killed

Date & Time: May 20, 2019 at 1556 LT
Type of aircraft:
Operator:
Registration:
N67667
Survivors:
No
Schedule:
Ketchikan – Metlakatla
MSN:
1309
YOM:
1959
Crew on board:
1
Crew fatalities:
Pax on board:
1
Pax fatalities:
Other fatalities:
Total fatalities:
2
Captain / Total flying hours:
1623
Captain / Total hours on type:
20.00
Aircraft flight hours:
29575
Circumstances:
The commercial pilot was conducting his first scheduled commuter flight from the company’s seaplane base to a nearby island seaplane base with one passenger and cargo onboard. According to company pilots, the destination harbor was prone to challenging downdrafts and changing wind conditions due to surrounding terrain. Multiple witnesses at the destination stated that the airplane made a westerly approach, and the wind was from the southeast with light chop on the water. Two witnesses reported the wings rocking left and right before touchdown. One witness stated that a wind gust pushed the tail up before the airplane landed. A different witness reported that the airplane was drifting right during the touchdown, and another witness saw the right (downwind) float submerge under water after touchdown, and the airplane nosed over as it pivoted around the right wingtip, which impacted the water. Flight track and performance data from the cockpit display units revealed that, as the airplane descended on the final approach, the wind changed from a right headwind of 6 knots to a left quartering tailwind of 8 knots before touchdown. The crosswind and tailwind components were within the airplane’s operational limitations. Examination of the airframe, engine, and associated systems revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation or egress. During the final approach and descent, the pilot had various wind information available to him; the sea surface wind waves and signatures, the nearest airport observation winds, the cockpit display calculated wind, and the visual relative ground speed. Had the pilot recognized that the winds had shifted to a quartering tailwind and the airplane’s ground speed was faster than normal, he could have aborted the landing and performed another approach into the wind. Although crosswind landings were practiced during flight training, tailwind landings were not because new pilots were not expected to perform them. Although the crosswind component was well within the airplane’s limits, it is possible that combined with the higher ground speed, the inexperienced pilot was unable to counteract the lateral drift during touchdown in a rapidly shifting wind. The pilot was hired the previous month with 5 hours of seaplane experience, and he completed company-required training and competency checks less than 2 weeks before the accident. According to the chief pilot (CP), company policy was to assign newly hired pilots to tour flights while they gained experience before assigning them to commuter flights later in the season. The previous year, the CP distributed a list of each pilot’s clearances for specific types of flights and destinations; however, an updated list had not been generated for the season at the time of the accident, and the flight coordinators, who were delegated operational control for assigning pilots to flights, and station manager were unaware of the pilot’s assignment limitations. Before the flight, the flight coordinator on duty completed a company flight risk assessment that included numerical values based on flight experience levels. The total risk value for the flight was in the caution area, which required management notification before releasing the flight, due to the pilot’s lack of experience in the accident airplane make and model and with the company, and his unfamiliarity with the geographical area; however, the flight coordinator did not notify management before release because the CP had approved a tour flight with the same risk value earlier in the day. Had the CP been notified, he may not have approved of the pilot's assignment to the accident flight. The pilot's minimal operational experience in seaplane operations likely affected his situational awareness in rapidly changing wind conditions and his ability to compensate adequately for a quartering tailwind at a higher-than-normal ground speed, which resulted in a loss of control during the water landing and a subsequent nose-over.
Probable cause:
The pilot’s inadequate compensation for a quartering tailwind during a water landing, which resulted in a loss of control and subsequent nose-over. Contributing to the accident was the company’s inadequate operational control of the flight release process, which resulted in assignment of an inexperienced pilot to a commuter seaplane flight.
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 Britten Norman BN-2B-27 Islander in Puerto Montt: 6 killed

Date & Time: Apr 16, 2019 at 1050 LT
Type of aircraft:
Registration:
CC-CYR
Flight Phase:
Survivors:
No
Site:
Schedule:
Puerto Montt - Ayacara
MSN:
2169
YOM:
1983
Country:
Crew on board:
1
Crew fatalities:
Pax on board:
5
Pax fatalities:
Other fatalities:
Total fatalities:
6
Captain / Total flying hours:
1414
Captain / Total hours on type:
437.00
Aircraft flight hours:
22330
Circumstances:
The twin engine airplane departed Puerto Montt-Marcel Marchant (La Paloma) Airport Runway 01 at 1050LT on a charter flight to Ayacara, carrying five passengers and one pilot. About 36 seconds after takeoff, while climbing, the pilot declared an emergency. The airplane entered a left turn then stalled and crashed onto a house located in a residential area, about 450 metres from the runway end, bursting into flames. The houses and the airplane were destroyed by a post crash fire and all six occupants were killed. One person in the house was injured.
Probable cause:
Loss of control of the airplane in flight, during a left turn, due to the failure of the right engine (n°2) during takeoff, caused by a fuel exhaustion.
The following contributing factors were identified:
- Failure of the pilot to comply with the pre takeoff checklist,
- Failure of the pilot to check the fuel selector switch and the fuel quantity prior to start the engines,
- Failure of the pilot to feather the propeller of the right engine (n°2) during an emergency situation,
- Failure of the pilot to bring the flaps to the neutral position during an emergency situation,
- Decrease of the speed and altitude of the airplane,
- Increase bank of the wing during a left turn.
Final Report:

Crash of a Boeing 737 MAX 8 near Debre Zeit: 157 killed

Date & Time: Mar 10, 2019 at 0844 LT
Type of aircraft:
Operator:
Registration:
ET-AVJ
Flight Phase:
Survivors:
No
Schedule:
Addis Ababa – Nairobi
MSN:
62450/7243
YOM:
2018
Flight number:
ET302
Country:
Region:
Crew on board:
8
Crew fatalities:
Pax on board:
149
Pax fatalities:
Other fatalities:
Total fatalities:
157
Captain / Total flying hours:
8122
Captain / Total hours on type:
1417.00
Copilot / Total flying hours:
361
Copilot / Total hours on type:
207
Aircraft flight hours:
1330
Aircraft flight cycles:
382
Circumstances:
On March 10, 2019, at 05:38 UTC, Ethiopian Airlines flight 302, Boeing 737-8(MAX), ET-AVJ, took off from Addis Ababa Bole International Airport bound to Nairobi, Kenya Jomo Kenyatta International Airport. ET302 was being operated under the provisions of the Ethiopian Civil Aviation Regulations (ECARAS) as a scheduled international flight between Addis Ababa Bole International Airport (HAAB), Ethiopia and Jomo Kenyatta Int. (HKJK) Nairobi, Kenya. It departed Addis Ababa with 157 persons on board: 2 flight crew (a Captain and a First Officer), 5 cabin crew and one IFSO, 149 regular passengers. At 05:36:12 the Airplane lined up on runway 07R at field elevation of 7,656 ft with flap setting of 5 degrees and a stabilizer trim setting of 5.6 units. Both flight directors (F/D) were ON with LNAV and VNAV modes armed. At 05:37:17the F/O reported to Tower ready for takeoff and at 05:37:36ATC issued take off clearance to ET-302 and advised to contact radar on 119.7MHz. The takeoff roll and lift-off was normal, including normal values of left and right angle-of-attack (AOA). During takeoff roll, the engines stabilized at about 94% N1. Shortly after liftoff, the left Angle of Attack sensor recorded value became erroneous and the left stick shaker activated and remained active until near the end of the recording. In addition, the airspeed and altitude values from the left air data system began deviating from the corresponding right side values. The left and right recorded AOA values began deviating. Left AOA decreased to 11.1° then increased to 35.7° while the right AOA indicated 14.94°. Then after, the left AOA value reached 74.5° in ¾ seconds while the right AOA reached a Maximum value of 15.3°, the difference between LH and RH AOA was59°and near the end of the recording it was 490. At 05:39:30, the radar controller identified ET-302 and advised to climb FL 340 and when able to turn right direct to RUDOL. At 5:39:51, the selected heading increased from 072° to 197°. After the flaps were fully retractedthe1stautomatic nose-down trim activated and engaged for 9 seconds positioning the stabilizer trim to 2.1 units. The pilot flying pulled to pitch up the Airplane with a force more than 90lbs. He then applied electric trim-up inputs. Five seconds after the end of these inputs a second automatic nose-down trim activated. At 5:40:22, the second automatic nose-down trim activated. Following nose-down trim activation GPWS DON’T SINK sounded for 3 seconds and “PULL UP” also displayed on PFD for 3 seconds. At 05:40:43, approximately five seconds after the end of the crew manual electrical trim up inputs, a third automatic trim nose-down was recorded but with no associated movement of the stabilizer. At 05:40:50, the captain told the F/O: “advise we would like to maintain one four thousand. We have a flight control problem”. The F/O complied and the request was approved by ATC. Following the approval of the ATC, the new target altitude of 14,000ft was set on the MCP. The Captain was unable to maintain the flight path and requested to return back to the departure airport. At 05:43:21, approximately five seconds after the last main electric trim up input, an automatic nose-down trim activated for about 5s. The stabilizer moved from 2.3 to 1 unit. The rate of climb decreased followed by a descent in 3s after the automatic trim activation. One second before the end of the automatic trim activation, the average force applied by the crew decreased from 100 lbs to 78 lbs in 3.5 seconds. In these 3.5 seconds, the pitch angle dropped from 0.5° nose up to -7.8° nose down and the descent rate increased from -100 ft/min to more than -5,000 ft/min. Following the last automatic trim activation and despite calculated column force of up to 110lbs, the pitch continued decreasing. The descent rate and the airspeed continued increasing between the triggering of the 4th automatic trim activation and the last recorded parameter value. At the end of the flight, Computed airspeed values reached 500Kt, Pitch values were greater than 40° nose down and descent rate values were greater than 33,000 ft/min. Finally, both recorders stopped recording at around 05 h 43 min 44s. At 05:44 The Airplane impacted terrain 28 NM South East of Addis Ababa near Ejere (located 8.8770 N, 39.2516 E.) village at a farm field and created a crater approximately 10 meters deep (last Airplane part found) with a hole of about 28 meters width and 40 meters length. Most of the wreckage was found buried in the ground; small fragments of the Airplane were found scattered around the site in an area by about 200 meters width and 300 meters long. The damages to the Airplane were consistent with a high energy impact. All 157 persons on board: 2 flight crew (a Captain and a First Officer), 5 cabin crew and one IFSO, 149 regular passengers were fatally injured.
Probable cause:
Repetitive and uncommanded airplane-nose-down inputs from the MCAS due to erroneous AOA input, and its unrecoverable activation system which made the airplane dive with the rate of -33,000 feet per minute close to the ground was the most probable cause of the accident.
The following contributing factors were identified:
1. The MCAS design relied on a single AOA sensor, making it vulnerable to erroneous input from the sensor;
2. During the design process, Boeing failed to consider the potential for uncommanded activation of MCAS, but assumed that pilots would recognize and address it through normal use of the control column, manual electric trim, and the existing Runaway Stabilizer NNC. The OMB and Emergency AD issued after the Lion Air accident included additional guidance but did not have the intended effect of preventing another MCAS-related accident;
3. While Boeing considered the possibility of uncommanded MCAS activation as part of its FHA, it did not evaluate all the potential alerts and indications that could accompany a failure leading to an uncommanded MCAS;
4. The MCAS contribution to cumulative AOA effects was not assessed;
5. The combined effect of alerts and indications that impacted pilot’s recognition and procedure prioritization were not evaluated by the Manufacturer;
6. Absence of AOA DISAGREE warning flag on the flight display panels (PFD);
7. The B737 MAX Crew difference CBT training prepared by Boeing and delivered to Pilots did not cover the MCAS system;
8. Failure by the manufacturer to design simulator training for pilots with regards to safety critical systems like MCAS with catastrophic consequences during undesired activation.
9. The manufacturer failed to provide procedures regarding MCAS operation to the crew during training or in the FCOM;
10. Failure by the manufacturer to address the safety critical questions raised by the airline which would have cleared out crew confusion and task prioritization;
Final Report:

Crash of an Embraer ERJ-145XR in Presque Isle

Date & Time: Mar 4, 2019 at 1129 LT
Type of aircraft:
Operator:
Registration:
N14171
Survivors:
Yes
Schedule:
Newark - Presque Isle
MSN:
145-859
YOM:
2004
Flight number:
UA4933
Crew on board:
3
Crew fatalities:
Pax on board:
28
Pax fatalities:
Other fatalities:
Total fatalities:
0
Captain / Total flying hours:
5655
Captain / Total hours on type:
1044.00
Copilot / Total flying hours:
4909
Copilot / Total hours on type:
470
Circumstances:
The first instrument landing system (ILS) approach to runway 1 appeared to be proceeding normally until the first officer (the pilot flying) transitioned from instrument references inside the flight deck to outside references. During a postaccident interview, the first officer stated that he expected to see the runway at that time but instead saw “white on white” and a structure with an antenna that was part of the runway environment but not the runway itself. The captain (the pilot monitoring) stated that she saw a tower and called for a go-around. (Both flight crewmembers were most likely seeing the automated weather observing system wind sensor pole, which was located about 325 ft to the right of the runway 1 centerline and about 870 ft beyond the runway threshold, and the damage to the lightning arrester at the top of the wind sensor pole was likely due to contact with the accident airplane as it flew over the pole.) According to the cockpit voice recorder (CVR), after the go-around, the first officer asked the captain if she saw the runway lights during the approach. The captain responded that she saw the lights but that “it’s really white down there that’s the problem.” Airport personnel stated that snow plowing operations on the runway had finished about 10 minutes before the first approach. The CVR recorded the flight crew’s discussion about turning on the pilot-controlled runway lights and sounds similar to microphone clicks before and after the discussion. However, the PQI maintenance foreman stated that, after the first approach, the runway lights were not on. Thus, the investigation could not determine, based on the available evidence, whether the flight crew had turned on the runway lights during the first approach. The captain thought that the airplane had drifted off course when the first officer transitioned from flight instruments to the outside, so she instructed the first officer to remain on the instruments during the second approach until the decision altitude (200 ft above ground level [agl]). The second approach proceeded normally with no problems capturing or maintaining the localizer and glideslope. During this approach, the captain asked airport maintenance personnel to ensure that the runway lighting was on, and the PQI maintenance foreman replied that the lights were on “bright”(the high-intensity setting). Thus, the flight crew had a means to identify the runway surface even with the reported snow cover at the time. As the airplane approached the decision altitude, the captain instructed the first officer to disconnect the autopilot, which he did. About nine seconds later, the airplane reached the decision altitude, and the captain called, “runway in sight twelve o’clock.” This callout was followed by the first officer’s statement, “I’m stayin’ on the flight director ‘cause I don’t see it yet.” A few seconds later, while the airplane was below 100 ft agl, the captain and the first officer expressed confusion, stating “what the [expletive]” and “I don’t know what I'm see in’,” respectively, but neither called for a go-around. The airplane subsequently impacted the snow-covered grassy area between runway 1 and a parallel taxiway. During a postaccident interview, the first officer stated that, when he transitioned from flight instruments to the outside during the second approach, he again saw “white on white” as well as blowing snow and that the airplane touched down before he could determine what he was seeing. The maintenance foreman estimated that, at the time of the accident, the runway had about 1/8 inch of snow with about 20% to 25% of the runway visible.
Probable cause:
The flight crew’s decision, due to confirmation bias, to continue the descent below the decision altitude when the runway had not been positively identified. Contributing to the accident were:
1) the first officer’s fatigue, which exacerbated his confirmation bias, and
2) the failure of CommutAir pilots who had observed the localizer misalignment to report it to the company and air traffic before the accident.
Final Report:

Crash of a Boeing 737-53C in La Paz

Date & Time: Nov 22, 2018 at 1013 LT
Type of aircraft:
Operator:
Registration:
OB-2041-P
Survivors:
Yes
Schedule:
Lima – Cuzco – La Paz
MSN:
24825/1894
YOM:
1990
Flight number:
P9331
Country:
Crew on board:
5
Crew fatalities:
Pax on board:
122
Pax fatalities:
Other fatalities:
Total fatalities:
0
Circumstances:
The airplane departed Lima on a schedule service to La Paz with an intermediate stop in Cuzco, carrying 122 passengers and a crew of five. Following an uneventful flight from Cuzco-Alejandro Velasco Astete Airport, the crew completed the approach to La Paz-El Alto Airport. After touchdown, the crew started the braking procedure when both main landing gear collapsed. The airplane slid on its belly for few dozen metres before coming to rest on runway 10. All 127 occupants evacuated safely and no one was injured. It was reported that the touchdown was considered as normal. The airplane was damaged beyond repair.

Crash of a Boeing 757-23N in Georgetown: 1 killed

Date & Time: Nov 9, 2018 at 0253 LT
Type of aircraft:
Operator:
Registration:
N524AT
Survivors:
Yes
Schedule:
Georgetown – Toronto
MSN:
30233/895
YOM:
1999
Flight number:
OJ256
Country:
Crew on board:
8
Crew fatalities:
Pax on board:
120
Pax fatalities:
Other fatalities:
Total fatalities:
1
Circumstances:
The airplane departed Georgetown-Cheddi Jagan Airport at 0209LT on an international schedule flight to Toronto-Lester Bowles Pearson Airport, carrying 120 passengers (118 adults and two children) and 8 crew members. At 0222LT, while climbing to 21,000 feet, the crew encountered technical problems with the hydraulic systems and was cleared to return. The captain made a 180 turn and followed a circuit and a holding pattern to burn fuel until he started the final approach to runway 06. After touchdown, the crew started the braking procedure but the airplane was apparently unable to stop within the remaining distance. Approaching the end of the runway, the aircraft veered to the right, lost its right main gear and came to rest in a sandy area with the right engine torn off and the right wing severely damaged. All 128 occupants evacuated, among them six were injured. One week later, on November 16, a 86 year old woman died from her injuries (fractured skull).

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

Date & Time: Nov 8, 2018 at 1054 LT
Type of aircraft:
Operator:
Registration:
RA-84674
Flight Phase:
Survivors:
Yes
Schedule:
Arkhangelsk – Soyana – Dolgoshchel’e – Mezen
MSN:
1G191-52
YOM:
1981
Flight number:
9135
Country:
Region:
Crew on board:
2
Crew fatalities:
Pax on board:
12
Pax fatalities:
Other fatalities:
Total fatalities:
0
Captain / Total flying hours:
4742
Captain / Total hours on type:
4336.00
Copilot / Total flying hours:
969
Copilot / Total hours on type:
761
Aircraft flight hours:
13509
Aircraft flight cycles:
20389
Circumstances:
The single engine airplane departed Arkhangelsk-Vaskovo Airport on a flight to Mezen with intermediate stops in Soyana and Dolgoshchel’e, carrying 12 passengers (11 adults and one child) and two pilots. En route, weather conditions deteriorated with drizzle. The crew reduced his altitude from 400 to 300 metres when frost formed on the windshield. The captain decided to return to Arkhangelsk but the aircraft' speed dropped from 170 to 120 km/h. Unable to maintain the speed and altitude, the crew attempted an emergency landing when the aircraft collided with trees and crashed in a wooded area located about 50 km northeast of Arkhangelsk-Talaghy Airport. All 14 occupants were rescued, among them two passengers were injured. The aircraft was destroyed.
Probable cause:
The accident with the An-2 RA-84674 aircraft occurred during a forced landing in the forest, the need for which was due to the impossibility of continuing the flight due to the effect of icing on the aerodynamic and traction characteristics of the aircraft (the inability to maintain altitude and speed even with the takeoff engine operating mode). The contributing factor, most likely, was the decision of the crew to climb over 150 m from the ground level, where the presence of stratus clouds and icing was predicted.
Final Report:

Crash of a Boeing 737 MAX 8 off Jakarta: 189 killed

Date & Time: Oct 29, 2018 at 0631 LT
Type of aircraft:
Operator:
Registration:
PK-LQP
Flight Phase:
Survivors:
No
Schedule:
Jakarta - Pangkal Pinang
MSN:
43000
YOM:
2018
Flight number:
JT610
Country:
Region:
Crew on board:
8
Crew fatalities:
Pax on board:
181
Pax fatalities:
Other fatalities:
Total fatalities:
189
Captain / Total flying hours:
6028
Captain / Total hours on type:
5176.00
Copilot / Total flying hours:
5174
Copilot / Total hours on type:
4286
Aircraft flight hours:
895
Aircraft flight cycles:
443
Circumstances:
The aircraft departed runway 25L at Jakarta-Soekarno-Hatta Airport at 0621LT bound for Pangkal Pinang, carrying 181 passengers and 8 crew members. The crew was cleared to climb but apparently encountered technical problems and was unable to reach a higher altitude than 5,375 feet. At this time, the flight shows erratic speed and altitude values. The pilot declared an emergency and elected to return to Jakarta when control was lost while at an altitude of 3,650 feet and at a speed of 345 knots. The airplane entered a dive and crashed 12 minutes after takeoff into the Kerawang Sea, about 63 km northeast from its departure point. The airplane disintegrated on impact and few debris were already recovered but unfortunately no survivors. It has been reported that the aircraft suffered various technical issues during the previous flight on Sunday night but was released for service on Monday morning. Brand new, the airplane was delivered to Lion Air last August 18. At the time of the accident, weather conditions were considered as good. The Cockpit Voice Recorder (CVR) was found on 14 January 2019. In the initial stages of the investigation, it was found that there is a potential for repeated automatic nose down trim commands of the horizontal stabilizer when the flight control system on a Boeing 737 MAX aircraft receives an erroneously high single AOA sensor input. Such a specific condition could among others potentially result in the stick shaker activating on the affected side and IAS, ALT and/or AOA DISAGREE alerts. The logic behind the automatic nose down trim lies in the aircraft's MCAS (Maneuvering Characteristics Augmentation System) that was introduced by Boeing on the MAX series aircraft. This feature was added to prevent the aircraft from entering a stall under specific conditions. On November 6, 2018, Boeing issued an Operations Manual Bulletin (OMB) directing operators to existing flight crew procedures to address circumstances where there is erroneous input from an AOA sensor. On November 7, the FAA issued an emergency Airworthiness Directive requiring "revising certificate limitations and operating procedures of the airplane flight manual (AFM) to provide the flight crew with runaway horizontal stabilizer trim procedures to follow under certain conditions.
Probable cause:
Contributing factors defines as actions, omissions, events, conditions, or a combination thereof, which, if eliminated, avoided or absent, would have reduced the probability of the accident or incident occurring, or mitigated the severity of the
consequences of the accident or incident. The presentation is based on chronological order and not to show the degree of contribution.
1. During the design and certification of the Boeing 737-8 (MAX), assumptions were made about flight crew response to malfunctions which, even though consistent with current industry guidelines, turned out to be incorrect.
2. Based on the incorrect assumptions about flight crew response and an incomplete review of associated multiple flight deck effects, MCAS’s reliance on a single sensor was deemed appropriate and met all certification requirements.
3. MCAS was designed to rely on a single AOA sensor, making it vulnerable to erroneous input from that sensor.
4. The absence of guidance on MCAS or more detailed use of trim in the flight manuals and in flight crew training, made it more difficult for flight crews to properly respond to uncommanded MCAS.
5. The AOA DISAGREE alert was not correctly enabled during Boeing 737-8 (MAX) development. As a result, it did not appear during flight with the mis-calibrated AOA sensor, could not be documented by the flight crew and was therefore not available to help maintenance identify the mis-calibrated AOA sensor.
6. The replacement AOA sensor that was installed on the accident aircraft had been mis-calibrated during an earlier repair. This mis-calibration was not detected during the repair.
7. The investigation could not determine that the installation test of the AOA sensor was performed properly. The mis-calibration was not detected.
8. Lack of documentation in the aircraft flight and maintenance log about the continuous stick shaker and use of the Runaway Stabilizer NNC meant that information was not available to the maintenance crew in Jakarta nor was it available to the accident crew, making it more difficult for each to take the appropriate actions.
9. The multiple alerts, repetitive MCAS activations, and distractions related to numerous ATC communications were not able to be effectively managed. This was caused by the difficulty of the situation and performance in manual handling, NNC execution, and flight crew communication, leading to ineffective CRM application and workload management. These performances had previously been identified during training and reappeared during the accident flight.
Final Report: