Country
code

Khyber Pakhtunkhwa (خیبرپختونخوا)

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 a Fokker F27 Friendship 200 in Chitral

Date & Time: Jun 16, 2004
Type of aircraft:
Operator:
Registration:
AP-AUR
Survivors:
Yes
Schedule:
Peshawar - Chitral
MSN:
10307
YOM:
1966
Flight number:
PK660
Country:
Region:
Crew on board:
4
Crew fatalities:
Pax on board:
36
Pax fatalities:
Other fatalities:
Total fatalities:
0
Circumstances:
After landing on runway 02 at Chitral Airport, the aircraft was unable to stop within the remaining distance. It overran, lost its undercarriage and came to rest in a grassy and sandy area. All 40 occupants evacuated safely and the aircraft was damaged beyond repair.

Crash of a Fokker F27 Friendship 200 near Kohat: 17 killed

Date & Time: Feb 20, 2003 at 0915 LT
Type of aircraft:
Operator:
Registration:
10254
Flight Type:
Survivors:
No
Site:
Schedule:
Islamabad - Kohat
MSN:
10254
YOM:
1964
Country:
Region:
Crew on board:
8
Crew fatalities:
Pax on board:
9
Pax fatalities:
Other fatalities:
Total fatalities:
17
Circumstances:
The aircraft departed Islamabad on a flight to Kohat, carrying nine passengers and eight crew members. While descending to Kohat, the crew encountered poor visibility when, at an altitude of 3,000 feet, the aircraft struck the slope of a mountain located 27 km from the airport. The aircraft disintegrated on impact and all 17 occupants were killed, among them Mushaf Ali Mir, Chief of Staff of the Pakistan Air Force and his wife. He was flying to Kohat with a delegation to perform the annual inspection of the airbase.
Probable cause:
Controlled flight into terrain after the crew initiated the descent prematurely, causing the aircraft to descend below the minimum safe altitude until it impacted ground. Poor weather conditions were considered as a contributing factor.

Crash of a Fokker F27 Friendship 200 in Dera Ismail Khan

Date & Time: Jul 6, 1994 at 1025 LT
Type of aircraft:
Operator:
Registration:
AP-ALN
Survivors:
Yes
Schedule:
Islamabad – Peshawar – Dera Ismail Khan
MSN:
10164
YOM:
1960
Flight number:
PK684
Country:
Region:
Crew on board:
4
Crew fatalities:
Pax on board:
38
Pax fatalities:
Other fatalities:
Total fatalities:
0
Circumstances:
On approach to Dera Ismail Khan Airport, the crew encountered technical problems with the left engine. The captain decided to initiate a go-around. Flaps and undercarriage were retracted when the aircraft entered a stall condition, lost height and crashed in an open field. It slid on the ground for about 300 metres before coming to rest against trees. All 42 occupants were evacuated, among them three passengers were injured.

Crash of a Fokker F27 Friendship 600 in Peshawar: 13 killed

Date & Time: Oct 23, 1986 at 2049 LT
Type of aircraft:
Operator:
Registration:
AP-AUX
Survivors:
Yes
Schedule:
Lahore - Peshawar
MSN:
10335
YOM:
1967
Country:
Region:
Crew on board:
5
Crew fatalities:
Pax on board:
49
Pax fatalities:
Other fatalities:
Total fatalities:
13
Aircraft flight hours:
39732
Aircraft flight cycles:
45472
Circumstances:
The descent to Peshawar Airport was completed in limited visibility caused by night. The copilot was in command when on final approach to runway 35, he descended below the MDA until the aircraft struck a dyke and crashed upside down about 10 km short of runway. 13 occupants were killed and 41 other were injured. The aircraft was destroyed.
Probable cause:
It was determined that the copilot was under a route check at the time of the accident and failed to initiate a go around procedure as he continued the approach below MDA. On his side, the captain was distracted from monitoring the altitude and failed to correctly supervise the copilot actions.

Crash of a Fokker F27 Friendship 600 near Jalkot: 31 killed

Date & Time: Dec 8, 1972 at 1215 LT
Type of aircraft:
Operator:
Registration:
AP-AUS
Flight Phase:
Survivors:
No
Site:
Schedule:
Gilgit - Rawalpindi
MSN:
10314
YOM:
1966
Flight number:
PK631
Country:
Region:
Crew on board:
5
Crew fatalities:
Pax on board:
26
Pax fatalities:
Other fatalities:
Total fatalities:
31
Aircraft flight hours:
11077
Aircraft flight cycles:
16720
Circumstances:
The airplane departed Gilgit Airport at 1140LT bound for Rawalpindi on flight PK631. En route, while cruising at an altitude of 9,000 feet in poor weather conditions, the airplane struck the slope of a snow covered mountain located near Jalkot. The wreckage was found few hours later and none of the 31 occupants survived the crash. At the time of the accident, the visibility was nil due to low clouds and snow falls. Apparently, the crew lost his orientation and maybe started the descent prematurely, causing the aircraft to struck the ground.
Probable cause:
Controlled flight into terrain.

Crash of a Fokker F27 Friendship 200 near Mahandri: 4 killed

Date & Time: Oct 8, 1965 at 0630 LT
Type of aircraft:
Operator:
Registration:
AP-ATT
Flight Phase:
Flight Type:
Survivors:
No
Site:
Schedule:
Rawalpindi – Skardu
MSN:
10279
YOM:
1965
Country:
Region:
Crew on board:
4
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
4
Captain / Total flying hours:
5640
Captain / Total hours on type:
3510.00
Copilot / Total flying hours:
865
Copilot / Total hours on type:
30
Aircraft flight hours:
491
Aircraft flight cycles:
528
Circumstances:
The aircraft took off from Rawalpindi Airport at 0601LT on a domestic flight to Skardu, carrying 9,146 pounds of food supplies. At 0604LT, it called Cherat Homer stating that it was due at control zone boundary at 0610LT. According to the Chakhlala ATC log the aircraft called Skardu at 0607LT on 119.7 but there was no response from Skardu on this frequency. According to the Skardu log: Skardu asked Gilgit at 0620LT to listen out for the aircraft and advise it to change over to 5514 kcs. The aircraft called Skardu at 0630LT on 5514 kcs. There was no further communication with the aircraft. It was subsequently found that the aircraft had struck the northern side of a ridge at an elevation of 13,100 feet just inside Pakistan territory near the Pakistan-Azad Kashmir border. The aircraft was destroyed and all four crew members were killed.
Probable cause:
The cause of the accident could not be determined with certainty.
Final Report:

Crash of a Douglas C-47A-1-DK near Lowari Pass: 22 killed

Date & Time: Mar 26, 1965
Operator:
Registration:
AP-AAH
Flight Phase:
Survivors:
Yes
Site:
Schedule:
Peshawar – Chitral
MSN:
12089
YOM:
1943
Country:
Region:
Crew on board:
4
Crew fatalities:
Pax on board:
22
Pax fatalities:
Other fatalities:
Total fatalities:
22
Circumstances:
While cruising in marginal weather conditions at an altitude of 9,000 feet, the airplane struck a mountain located near the Lowari Pass. Four passengers were seriously injured while 22 other occupants were killed.

Crash of a Douglas C-47 Dakota IV near Chitral: 11 killed

Date & Time: Oct 17, 1946
Operator:
Registration:
KN236
Flight Phase:
Flight Type:
Survivors:
No
Site:
MSN:
15659/27104
YOM:
1945
Country:
Region:
Crew on board:
3
Crew fatalities:
Pax on board:
8
Pax fatalities:
Other fatalities:
Total fatalities:
11
Circumstances:
While cruising at an altitude of 10,000 feet in a valley, the aircraft hit the slope of a mountain and crashed. All 11 occupants were killed. It was reported that the aircraft was overloaded.