Country

Crash of an ATR42-500 off Bukoba: 19 killed

Date & Time: Nov 6, 2022 at 0853 LT
Type of aircraft:
Operator:
Registration:
5H-PWF
Survivors:
Yes
Schedule:
Dar es-Salaam – Bukoba
MSN:
819
YOM:
2010
Flight number:
PW494
Country:
Region:
Crew on board:
4
Crew fatalities:
Pax on board:
39
Pax fatalities:
Other fatalities:
Total fatalities:
19
Circumstances:
On final approach to Bukoba Airport, the crew encountered poor visibility due to heavy rain falls. In circumstances that need to be clarified, the airplane descended too low, impacted the water surface and crashed into Lake Victoria, about 100 metres short of runway 31. Fishermen with several boats were quickly on the scene and were able to evacuate 24 people. Unfortunately, 19 others including both pilots were killed. The aircraft sank by a depth about 3-4 metres.

Crash of an ATR42-500 in Gilgit

Date & Time: Jul 20, 2019 at 0815 LT
Type of aircraft:
Operator:
Registration:
AP-BHP
Survivors:
Yes
Schedule:
Islamabad – Gilgit
MSN:
665
YOM:
2007
Country:
Region:
Crew on board:
5
Crew fatalities:
Pax on board:
48
Pax fatalities:
Other fatalities:
Total fatalities:
0
Circumstances:
Following an uneventful flight from Islamabad, the crew was cleared to land on runway 25 at Gilgit Airport. After touchdown, the crew initiated the braking procedure but the aircraft was unable to stop within the remaining distance. It overran, lost its right main gear and came to rest 12 metres further in a grassy area. All 53 occupants evacuated safely and the aircraft was damaged beyond repair.

Crash of an ATR42-500 near Havelian: 47 killed

Date & Time: Dec 7, 2016 at 1620 LT
Type of aircraft:
Operator:
Registration:
AP-BHO
Flight Phase:
Survivors:
No
Site:
Schedule:
Chitral – Islamabad
MSN:
663
YOM:
2007
Flight number:
PK661
Country:
Region:
Crew on board:
5
Crew fatalities:
Pax on board:
42
Pax fatalities:
Other fatalities:
Total fatalities:
47
Captain / Total flying hours:
11265
Captain / Total hours on type:
1216.00
Copilot / Total flying hours:
570
Copilot / Total hours on type:
369
Aircraft flight hours:
18739
Circumstances:
On 07 December 2016 morning, after a routine daily inspection at Benazir Bhutto International Airport (BBIAP) Islamabad, Pakistan International Airlines (PIA) aircraft ATR42-500 Reg No AP-BHO operated 05 flights (ie Islamabad to Gilgit and back, Islamabad to Chitral, Chitral to Peshawar and back). As 6th and last flight of that day, it took off from Chitral at time 10:38:50 UTC (15:38:50 PST) with 42 passengers (including 01 engineer) and 05 crew members (03 pilots and 02 cabin crew) aboard for Islamabad. It crashed after 42 minutes of flight at 11:20:38 UTC (16:20:38 PST) about 3.5 Nautical Miles (NM) SSE of Havelian, and 24 NM North of BBIAP Islamabad. All 47 souls aboard were fatally injured. The aircraft remained in air for about 42 minutes before crash (all timings in UTC). These 42 minutes have been split into three stages of flight, described hereunder:

(a) Initial Stage: From 10:38 to 11:04 (~26 minutes) degraded speed governing accuracy of the port propeller was evident in the DFDR data, but was apparently not observed by the cockpit crew. The flight stabilized at an altitude 13,500 feet AMSL and a cruising speed of 186 knots IAS (instead of expected 230 knots IAS). There were two latent pre-existing technical anomalies in the aircraft (a Fractured / dislodged PT-1 blade due to a known quality issue and a fractured pin inside the OSG), and one probable latent pre-existing condition (external contamination) inside the PVM of No 1 Engine. Digital Flight Data Recorder (DFDR) analysis indicates that No 1 Engine was degraded.

(b) Middle Stage (Series of Technical Malfunctions): From 11:04 to 11:13 (~09 minutes), a series of warnings and technical malfunctions occurred to No 1 Engine (left side) and its related propeller control system. These included Propeller Electronic Control (PEC) fault indications, followed by No 1 Engine power loss, and uncontrolled variation of its propeller speed / blade pitch angle abnormal system operation). The propeller speed which was initially at 82% (cruise setting) decreased gradually to 62% and later at the time of engine power loss it increased to 102% (and stayed at that value for about 15 to 18 seconds). It then reduced down to Non Computed Data (NCD) as per DFDR. At this point, (based on simulation results) the blade pitch angle increased (possibly close to feather position). Later, the propeller speed increased to 120% to 125% (probably caused due to unusual technical malfunctions) and stayed around that value for about 40 to 45 seconds. It finally showed an abrupt drop down to NCD again. At this point, (based on simulation results) the blade pitch angle may have settled at a value, different from the expected feathered propeller. During this unusual variation of propeller speed, there were drastic variations in the aircraft aerodynamic behaviour and sounds. The directional control was maintained initially by the Auto-Pilot. A relatively delayed advancement of power (of No 2 Engine) post No 1 Engine power loss, reduction of power (of No 2 Engine) for about 15 seconds during the timeframe when left propeller rpm was in the range of 120% to 125%, and once again a reduction of power towards the end of this part of flight, were incorrect pilot actions, and contributed in the IAS depletion. Auto-Pilot got disengaged. Towards the end of this part of flight, the aircraft was flying close to stall condition. No 1 Engine was already shutdown and No 2 Engine (right side) was operating normal. At this time, IAS was around 120 knots; aircraft started to roll / turn left and descend. Stick shaker and stick pusher activated. Calculated drag on the left side of the aircraft peaked when the recorded propeller speed was in the range of 120% to 125%. During transition of propeller speed to NCD, the additional component of the drag (possibly caused due to abnormal behaviour of left propeller) suddenly reduced. The advancement of power of No 2 Engine was coupled with excessive right rudder input (to counter the asymmetric condition). This coincided with last abrupt drop in the propeller speed. As a combined effect of resultant aerodynamic forces aircraft entered into a stalled / uncontrolled flight condition, went inverted and lost 5,100 feet AMSL altitude (ie from ~13,450 feet to 8,350 feet AMSL).

(c) Final Stage: The final stage of flight from 11:13 to 11:20 (~07 minutes) started with the aircraft recovering from the uncontrolled flight. Although blade pitch position was not recorded (in the DFDR – by design), and it was not possible to directly calculate that from the available data, a complex series of simulations and assumptions estimated that the blade pitch of left propeller may have settled at an angle around low pitch in flight while rotating at an estimated speed of 5%. Aircraft simulations indicated that stable additional drag forces were present on the left side of the aircraft at this time and during the remaining part of flight. Aircraft had an unexpected (high) drag from the left side (almost constant in this last phase); the aircraft behavior was different from that of a typical single engine In Flight Shutdown (IFSD) situation. In this degraded condition it was not possible for the aircraft to maintain a level flight. However, that level of drag did not preclude the lateral control of the aircraft, if a controlled descent was initiated. The aircraft performance was outside the identified performance envelope. It was exceptionally difficult for the pilots to understand the situation and hence possibly control the aircraft. Figure hereunder shows different stages of flight.
Probable cause:
The following factors were reported:
Probable Primary Factors:
(a) The dislodging / fracture of one PT-1 blade of No 1 Engine triggered a chain of events. Unusual combination of fractured / dislodged PT-1 blade with two latent factors caused off design performance of the aircraft and resulted into the accident.
(b) The dislodging / fracture of PT-1 blade of No 1 Engine occurred after omission from the EMM (Non-Compliance of SB-21878) by PIA Engineering during an unscheduled maintenance performed on the engine in November 2016, in which the PT-1 blades had fulfilled the criteria for replacement, but were not replaced.
(c) Fracture / dislodging of PT-1 blade in No 1 Engine, after accumulating a flying time slightly more than the soft life of 10,000 hrs (ie at about 10004.1 + 93 hrs) due to a known quality issue. This aspect has already been addressed by re-designing of PT-1 blades by P&WC.
Probable Contributory Factors:
(a) A fractured pin (and contamination inside the OSG), contributed to a complex combination of technical malfunctions. The pin fractured because of improper re-assembly during some unauthorized / un-documented maintenance activity. It was not possible to ascertain exact time and place when and where this improper re-assembly may have occurred.
(b) Contamination / debris found in overspeed line of PVM of No 1 Engine probably introduced when the propeller system LRU"s were not installed on the gearbox, contributed to un-feathering of the propeller. It was not possible to ascertain exact time and place when and where this contamination was introduced.
Final Report:

Crash of an ATR42-500 in Coari

Date & Time: May 30, 2014 at 2055 LT
Type of aircraft:
Operator:
Registration:
PR-TKB
Flight Phase:
Survivors:
Yes
Schedule:
Coari - Manaus
MSN:
610
YOM:
2000
Location:
Country:
Crew on board:
4
Crew fatalities:
Pax on board:
45
Pax fatalities:
Other fatalities:
Total fatalities:
0
Captain / Total hours on type:
2601.00
Copilot / Total flying hours:
5898
Copilot / Total hours on type:
548
Circumstances:
During the takeoff roll from Coari-Urucu Airport by night, the aircraft collided with a tapir that struck the right main gear. The crew continued the takeoff procedure and the flight to Manaus. After two hours and burning fuel, the aircraft landed at Manaus-Eduardo Gomes Airport. Upon touchdown, the right main gear collapsed and the aircraft veered to the right and came to rest. All 49 occupants evacuated safely while the aircraft was damaged beyond repair.
Probable cause:
Collision with a tapir during takeoff, causing severe damages to the right main gear.
The following findings were identified:
- The lack of isolation of the operational area allowed the land animal to enter the runway for landings and takeoffs, contributing to the accident.
- The crew did not notice the presence of the land animal on the runway early enough to abort the takeoff without extrapolating the runway limits and avoiding collision.
- The presence of the land animal (Tapirus terrestris) interfered with the operation and led to the collision of the right main landing gear.
Final Report:

Crash of an ATR42-500 in Lahore

Date & Time: Aug 31, 2012 at 1510 LT
Type of aircraft:
Operator:
Registration:
AP-BHJ
Survivors:
Yes
Schedule:
Islamabad - Lahore
MSN:
657
YOM:
2006
Flight number:
PK653
Country:
Region:
Crew on board:
4
Crew fatalities:
Pax on board:
42
Pax fatalities:
Other fatalities:
Total fatalities:
0
Circumstances:
Following an uneventful flight from Islamabad, the crew started the descent to runway 36R in marginal weather conditions. Upon touchdown on a wet runway, the right main gear collapsed. The aircraft slid for about 1,700 feet before exiting the runway to the right and coming to rest 60 feet further on. All 46 occupants were unhurt while the aircraft was considered as damaged beyond repair. Five minutes after the accident, the weather briefing was as follow: OPLA 311015Z 16009KT 3000 RA BKN040 OVC100 29/24 Q1003. But ten minutes prior to the crash, the weather briefing was as follow: OPLA 311000Z 33008KT 4000 -RA SCT040 BKN100 32/24 Q1002 TEMPO 31030KT 2000 TSRA FEW030CB. Thus, the conditions were considered as marginal with turbulences, wind to 30 knots and CB's at 3,000 feet. On 11SEP2012, the French BEA reported that the aircraft touched down just at the beginning of the paved surface (undershoot area) to the right of the extended runway 36R centerline, causing the right main gear to collapse. It was reported that the aircraft was unstable on short final and that the crew failed to initiate a go-around procedure while the aircraft was too low on the glide.