Crash of a Piper PA-31-310 Navajo C in Aldinga

Date & Time: Jan 29, 2014 at 1132 LT
Type of aircraft:
Operator:
Registration:
VH-OFF
Flight Phase:
Flight Type:
Survivors:
Yes
Schedule:
Aldinga - Kangaroo Island
MSN:
31-7812064
YOM:
1978
Country:
Region:
Crew on board:
1
Crew fatalities:
Pax on board:
1
Pax fatalities:
Other fatalities:
Total fatalities:
0
Circumstances:
On 29 January 2014, at about 1100 Central Daylight-savings Time, the pilot prepared a Piper PA-31 aircraft, registered VHOFF, for a private flight from Aldinga aeroplane landing area (ALA) to Kangaroo Island, South Australia. To check fuel quantities, the pilot entered the cockpit, turned on the master switch and placed the left and right fuel selectors onto the main tank (inboard) position. The gauge for each tank showed just under half full. He then placed each fuel selector onto the auxiliary (outboard) tank position, where the gauge indicated the right and left auxiliary tanks were each about a quarter full. He did not return the selectors to the main tanks. He estimated that refuelling the main tanks would allow sufficient fuel for the flight with over an hour in reserve. He exited the aircraft while it was refuelled and continued preparing for the flight. Once refuelling was completed, the pilot conducted a pre-flight inspection, and finished loading the aircraft. The pilot and passenger then boarded. The pilot was familiar with Aldinga ALA, which is a non-controlled airport. At uncontrolled airports, unless a restriction or preference is listed for a certain runway in either the Airservices en route supplement Australia (ERSA), or other relevant publications, selection of the runway is the responsibility of the pilot. Operational considerations such as wind direction, other traffic, runway surface and length, performance requirements for the aircraft on that day, and suitable emergency landing areas in the event of an aircraft malfunction are all taken into consideration. On this day, the pilot assessed the wind to be favoring runway 14, which already had an aircraft in the circuit intending to land. However, he decided to use runway 03 due to the availability of a landing area in case of an emergency. He then completed a full run-up check of the engines, propellers and magnetos prior to lining up for departure. The pilot reported that all of the pre-take-off checks were normal. Once the aircraft landing on runway 14 was clear of the runway, the pilot went through his usual memory checklist prior to take-off. He scanned and crosschecked the flight and panel instruments, power quadrant settings and trims, but did not complete his usual final check, which was to reach down with his right hand and confirm that the fuel selector levers were on the main tanks. After broadcasting on the common traffic advisory frequency (CTAF) he commenced the take-off. At the appropriate speed, he rotated the aircraft as it passed the intersection of the 14 and 03 runways. Almost immediately both engines began surging, there was a loss of power, the power gauges fluctuated and the aircraft yawed from side to side. Due to the surging, fluctuating gauges and aircraft yaw, the pilot found it difficult to identify what he thought was a non-performing engine. He reported there were no warning lights so he retracted the landing gear, with the intent of getting the aircraft to attain a positive rate of climb, so he could trouble shoot further at a safe altitude. When a little over 50 ft above ground level (AGL), he realized the aircraft was not performing sufficiently, so he selected a suitable landing area. He focused on maintaining a safe airspeed and landed straight ahead. The aircraft touched down and slid about another 75-100 metres before coming to rest. The impact marks of the propellers suggest the aircraft touched the ground facing north-easterly and rotated to the north-west prior to stopping. The pilot turned off the master switch and both he and the passenger exited the aircraft. After a few minutes he re-entered the cockpit and completed the shutdown. Police and fire service attended shortly after the accident.
Probable cause:
Engine malfunction due to fuel starvation.
Final Report:

Crash of a Boeing 737-3B7(SF) in Honiara

Date & Time: Jan 26, 2014 at 1259 LT
Type of aircraft:
Operator:
Registration:
ZK-TLC
Flight Type:
Survivors:
Yes
Schedule:
Brisbane – Honiara
MSN:
23705/1497
YOM:
1988
Flight number:
PAQ523
Region:
Crew on board:
3
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
0
Circumstances:
Following an uneventful flight from Brisbane, the crew completed the approach and landing at Honiara-Henderson Airport. After touchdown on runway 24, the right main gear collapsed and punctured the right wing. The aircraft veered slightly to the right and came to a halt on the runway. All three occupants evacuated safely and the aircraft was damaged beyond repair.
Probable cause:
The failure of the right main gear was the consequence of an inappropriate rework (ie, machining and re-threading) of the tee-bolt fitting and the associated installation of a reduced size nut and washer, during the last overhaul in 2004.

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

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

Crash of an ATR42-320F in Madang

Date & Time: Oct 19, 2013 at 0915 LT
Type of aircraft:
Operator:
Registration:
P2-PXY
Flight Phase:
Flight Type:
Survivors:
Yes
Schedule:
Madang – Tabubil – Kiunga
MSN:
87
YOM:
1988
Flight number:
PX2900
Location:
Region:
Crew on board:
3
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
0
Captain / Total flying hours:
7110
Captain / Total hours on type:
3433.00
Copilot / Total flying hours:
3020
Copilot / Total hours on type:
2420
Aircraft flight hours:
24375
Circumstances:
On 19 October 2013, an Avions de Transport Régional ATR42-320 freighter, registered P2-PXY (PXY) and operated by Air Niugini, was scheduled to fly from Madang to Tabubil, Western Province, as flight PX2900 carrying a load tobacco for a client company. There were three persons on board; the pilot in command (PIC), a copilot, and a PNG experienced DHC-8 captain whose function was to provide guidance during the approach into Tabubil. The PIC was the handling pilot and the copilot was the support monitoring pilot. The flight crew taxied to the threshold end of runway 25 intending to use the full length of the runway. The take-off roll was normal until the PIC tried to rotate at VR (speed for rotation, which the flight crew had calculated to be 102 knots). He subsequently reported that the controls felt very heavy in pitch and he could not pull the control column back in the normal manner. Flight data recorder (FDR) information indicated that approximately 2 sec later the PIC aborted the takeoff and selected full reverse thrust. He reported later that he had applied full braking. It was not possible to stop the aircraft before the end of the runway and it continued over the embankment at the end of the runway and the right wing struck the perimeter fence. The aircraft was substantially damaged during the accident by the impact, the post-impact fire and partial immersion in salt water. The right outboard wing section was completely burned, and the extensively damaged and burnt right engine fell off the wing into the water. Both propellers were torn from the engine shafts and destroyed by the impact forces.
Probable cause:
The following findings were identified:
- The investigation found that Air Niugini’s lack of robust loading procedures and supervision for the ATR 42/72 aircraft, and the inaccurate weights provided by the consignor/client company likely contributed to the overload.
- The mass and the centre of gravity of the aircraft were not within the prescribed limits.
- The aircraft total load exceeded the maximum permissible load and the load limit in the forward cargo zone ‘A’ exceeded the zone ‘A’ structural limit.
- There was no evidence of any defect or malfunction in the aircraft that could have contributed to the accident.
Final Report:

Crash of a Cessna 207A Stationair 8 II in Mount Nicholas

Date & Time: Aug 2, 2013 at 0915 LT
Operator:
Registration:
ZK-LAW
Flight Phase:
Flight Type:
Survivors:
Yes
MSN:
207-0723
YOM:
1981
Country:
Region:
Crew on board:
2
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
0
Circumstances:
The crew was completing a training mission. In unknown circumstances, the single engine aircraft crashed in a prairie located near Mount Nicholas, between Queenstown and Te Anau, coming to rest upside down. Both pilots were seriously injured and the aircraft was destroyed.

Crash of a Britten Norman BN-2B-26 Islander at Okiwi Station

Date & Time: Jan 25, 2013 at 0827 LT
Type of aircraft:
Operator:
Registration:
ZK-DLA
Survivors:
Yes
Schedule:
Auckland – Okiwi Station
MSN:
2131
YOM:
1984
Country:
Region:
Crew on board:
1
Crew fatalities:
Pax on board:
8
Pax fatalities:
Other fatalities:
Total fatalities:
0
Captain / Total flying hours:
3170
Captain / Total hours on type:
296.00
Circumstances:
On approach to runway 18 at Okiwi, New Zealand, the aircraft encountered windshear on short final as the pilot reduced power to land. The pilot was unable to arrest the descent rate and the aircraft landed heavily. Damage was caused to both landing gear oleos and one brake unit, with rippling found on the upper and lower skin of each wing. One passenger sustained a back injury, which was later identified as a fractured vertebra. The pilot was aware of fluctuating wind conditions at Okiwi and had increased the approach speed to 70 knots as per company standard operating procedures. The pilot reported that despite this, the airspeed reduced rapidly and significantly at 10 to 15 feet agl, leaving little time to react to the situation.
Probable cause:
Loss of height and hard landing due to windshear on short final.

Crash of a PAC Cresco 08-600 in Waitaanga

Date & Time: Dec 11, 2012 at 1738 LT
Type of aircraft:
Operator:
Registration:
ZK-LTR
Flight Phase:
Survivors:
Yes
Schedule:
Taumatunui - Mount Messenger
MSN:
003
YOM:
1980
Country:
Region:
Crew on board:
1
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
0
Circumstances:
The aircraft crashed in unknown circumstances in Waitaanga while completing a spraying mission between Taumatunui and Mount Messenger. The aircraft was destroyed and the pilot, sole on board, was seriously injured.

Crash of a Fletcher FU-24A-954 near Rotorua: 1 killed

Date & Time: Dec 8, 2012 at 1315 LT
Type of aircraft:
Operator:
Registration:
ZK-EMX
Flight Phase:
Survivors:
No
MSN:
278
YOM:
1981
Country:
Region:
Crew on board:
1
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
1
Captain / Total flying hours:
430
Captain / Total hours on type:
95.00
Aircraft flight hours:
11300
Circumstances:
The pilot, who was undertaking training toward a Grade 2 Agricultural Pilot Rating, began work at approximately 0625 hours on the day of the accident. The pilot and his instructor, who was in another topdressing aircraft, flew to a block of land to the south east of Rotorua where the pilot completed 15 sowing runs, while his instructor worked in the local vicinity in the second aircraft. The pilot and instructor completed the work on this block, had a break and then transited to the Waikite Valley, arriving at approximately 0945 hours. At 1045 hours, after refuelling his aircraft, the pilot commenced sowing a ‘special mix’ fertiliser, in an alternating pattern between the instructor and pilot, with two aircraft operating from the airstrip. The alternating pattern allowed the instructor to observe and supervise the pilot during the take off and landing phases, while allowing the operation to proceed efficiently. The pilot and instructor stopped for lunch after an hour of flying, refuelled once more and then continued with their work. The amount of fertiliser that was loaded into the pilot’s aircraft was progressively increased as the work proceeded. The initial load of product was 900 kg, gradually increasing by 50 kg increments, when the instructor was satisfied that the pilot’s performance allowed this increase. The last five loads carried prior to the accident were each 1100 kg. Nothing untoward was noticed during the sowing runs, apart from the pilot aborting one landing attempt, due to the wake turbulence from the instructor’s aircraft during take off. At the time of the accident the pilot was performing ‘clearing runs’, sowing on remaining areas of land not already covered by previous sowing runs. Immediately prior to the accident, the pilot called the instructor on the radio to enquire of his location. The instructor responded with “directly behind you on the other side of the woolshed”. A few seconds later, as the instructor approached to land at the airstrip, he observed the pilot’s aircraft flying in a westerly direction at approximately 400 ft AGL. He then saw the pilot’s aircraft make a slight turn to the left. Describing what he had seen as: “he started to climb and turn slightly to the left, then the plane was in a left hand spin”. The instructor thought at the time that the aircraft spun for one and a half rotations to the left, prior to being obscured by the ridge adjacent to the airstrip. The accident occurred in daylight, at approximately 1315 hours, at Waikite Valley, Rotorua, at an elevation of 1460 ft. Latitude S 38° 18.5', longitude E 176° 17.42'.
Probable cause:
Conclusions
- The pilot was appropriately licensed and held a valid medical certificate.
- The aircraft had been appropriately maintained and no technical discrepancy was discovered that could have contributed to the accident.
- It is likely that, during a climbing turn, the pilot inadvertently allowed an aerodynamic stall to occur at which point the aircraft suddenly departed controlled flight.
- No emergency jettison of the hopper contents was attempted.
- The height above the ground, was insufficient for the pilot to perform a successful recovery once the departure from controlled flight had fully developed.
- The pilot’s lack of experience with agricultural operations and relative unfamiliarity with the aircraft type could not be eliminated as having a bearing on the accident.
Final Report:

Crash of a De Havilland DH.84 Dragon near Borumba Dam: 6 killed

Date & Time: Oct 1, 2012 at 1413 LT
Type of aircraft:
Operator:
Registration:
VH-UXG
Flight Phase:
Flight Type:
Survivors:
No
Schedule:
Monto - Caboolture
MSN:
6077
YOM:
1934
Country:
Region:
Crew on board:
1
Crew fatalities:
Pax on board:
5
Pax fatalities:
Other fatalities:
Total fatalities:
6
Captain / Total flying hours:
1134
Captain / Total hours on type:
662.00
Circumstances:
At about 1107 Eastern Standard Time on 01OCT2012, a de Havilland Aircraft Pty Ltd DH-84 Dragon, registered VH-UXG (UXG), took off from Monto on a private flight to Caboolture, Queensland under the visual flight rules (VFR). On board the aircraft were the pilot/owner and five passengers. The weather conditions on departure were reported to include a light south-easterly wind with a high overcast and good visibility. Sometime after about 1230, the aircraft was seen near Tansey, about 150 km north-west of Caboolture on the direct track from Monto to Caboolture. The aircraft was reported flying in a south-easterly direction at the time, at an estimated height of 3,000 ft and in fine but overcast conditions. At 1315, the pilot contacted Brisbane Radar air traffic control (ATC) and advised that the aircraft’s position was about 37 NM (69 km) north of Caboolture and requested navigation assistance. At 1318, the pilot advised ATC that the aircraft was in ‘full cloud’. For most of the remainder of the flight, the pilot and ATC exchanged communications, at times relayed through a commercial flight and a rescue flight in the area due to the limited ATC radio coverage in the area at low altitude. At about 1320, a friend of one of the aircraft’s passengers received a telephone call from the passenger to say that she was in an aircraft and that they were ‘lost in a cloud’ and kept losing altitude. Witnesses in the Borumba Dam, Imbil and Kandanga areas 70 to 80 km north-north-west of Caboolture later reported that they heard and briefly saw the aircraft flying in and out of low cloud between about 1315 and 1415. At 1348, the pilot advised ATC that the aircraft had about an hour’s endurance remaining. The pilot’s last recorded transmission was at 1404. A search for the aircraft was coordinated by Australian Search and Rescue (AusSAR). The aircraft wreckage was located on 3 October 2012, about 87 km north-west of Caboolture on the northern side of a steep, densely wooded ridge about 500 m above mean sea level. The Australian Transport Safety Bureau (ATSB) later determined that the aircraft probably impacted terrain at about 1421 on 01OCT2012. Preliminary analysis indicated that the aircraft collided with trees and terrain at a moderate to high speed, with a left angle of bank. The aircraft’s direction of travel at impact was toward the south-south-west.
Probable cause:
From the evidence available, the following findings are made with respect to the visual flight rules into instrument meteorological conditions accident involving de Havilland Aircraft Pty Ltd DH-84 Dragon, registered VH-UXG, that occurred 36 km south-west of Gympie, Queensland, on 1 October 2012. These findings should not be read as apportioning blame or liability to any particular organisation or individual. Safety issues, or system problems, are highlighted in bold to emphasize their importance. A safety issue is an event or condition that increases safety risk and (a) can reasonably be regarded as having the potential to adversely affect the safety of future operations, and (b) is a characteristic of an organisation or a system, rather than a characteristic of a specific individual, or characteristic of an operating environment at a specific point in time.
Contributing factors:
- The pilot unintentionally entered instrument meteorological conditions and was unable to reattain and maintain visual conditions.
- It is likely that the pilot became spatially disoriented and lost control due to a combination of factors such as the absence of a visible horizon, cumulative workload, stress and/or distraction.
Other factors that increased risk:
- Though it probably did not have a significant bearing on the event, the aircraft was almost certainly above its maximum take-off weight (MTOW) on take-off, and around the MTOW at the time of the accident.
- Though airborne search and rescue service providers were regularly tasked to provide assistance to pilots in distress, there was limited specific guidance on the conduct of such assistance. Other findings:
- The aircraft wreckage was not located for 2 days as the search was hindered by difficult local weather conditions and terrain, and the cessation of the aircraft’s emergency beacon due to impact damage.
Final Report:

Crash of a De Havilland DHC-8-100 near Madang: 28 killed

Date & Time: Oct 13, 2011 at 1717 LT
Operator:
Registration:
P2-MCJ
Survivors:
Yes
Schedule:
Port Moresby - Lae - Madang
MSN:
125
YOM:
1988
Flight number:
CG1600
Location:
Region:
Crew on board:
4
Crew fatalities:
Pax on board:
28
Pax fatalities:
Other fatalities:
Total fatalities:
28
Captain / Total flying hours:
18200
Captain / Total hours on type:
500.00
Copilot / Total flying hours:
2725
Copilot / Total hours on type:
391
Aircraft flight hours:
38421
Aircraft flight cycles:
48093
Circumstances:
On the afternoon of 13 October 2011, an Airlines PNG Bombardier DHC-8-103, registered P2-MCJ (MCJ), was conducting a regular public transport flight from Nadzab, Morobe Province, to Madang, Madang Province under the Instrument Flight Rules (IFR). On board the aircraft were two flight crew, a flight attendant, and 29 passengers. Earlier in the afternoon, the same crew had flown MCJ from Port Moresby to Nadzab. The autopilot could not be used because the yaw damper was unserviceable so the aircraft had to be hand-flown by the pilots. At Nadzab, the aircraft was refuelled with sufficient fuel for the flight to Madang and a planned subsequent flight from Madang to Port Moresby. MCJ departed Nadzab at 1647 LMT with the Pilot-in-Command as the handling pilot. The aircraft climbed to 16,000 ft with an estimated arrival time at Madang of 1717. Once in the cruise, the flight crew diverted right of the flight planned track to avoid thunderstorms and cloud. The Pilot-in-Command reported that communications between Madang Tower and an aircraft in the vicinity of Madang indicated a storm was approaching the aerodrome. He recalled that he had intended to descend below the cloud in order to be able to see across the sea to Madang and had been concentrating on manoeuvring the aircraft to remain clear of thunderstorms and cloud, so he had been looking mainly outside the cockpit. Because of the storm in the vicinity of the airport, he said there had been „some urgency‟ to descend beneath the cloud base to position for a right base for runway 07 at Madang, the anticipated approach. On this route, the descent to Madang was steep (because of the need to remain above the Finisterre Ranges until close to Madang) and, although the aircraft was descending steeply, the propellers were at their cruise setting of 900 revolutions per minute (RPM). Neither pilot noticed the airspeed increasing towards the maximum operating speed (VMO); the Pilot-in-Command reported afterwards that he had been „distracted‟ by the weather. When the aircraft reached VMO as it passed through 10,500 ft, with a rate of descent between 3,500 and 4,200 ft per minute, and the propellers set at 900 RPM, the VMO overspeed warning sounded. The Pilot-in-command reported that he had been about to ask the First Officer to increase the propeller speed to 1,050 RPM to slow the aircraft when this occurred. He raised the nose of the aircraft in response to the warning and this reduced the rate of descent to about 2,000 ft per minute, however, the VMO overspeed warning continued. The First Officer recalled the Pilot-in-Command moved the power levers back „quite quickly‟. Shortly after the power levers had been moved back, both propellers oversped simultaneously, exceeding their maximum permitted speed of 1,200 RPM by over 60 % and seriously damaging the left hand engine and rendering both engines unusable. Villagers on the ground reported hearing a loud „bang‟ as the aircraft passed overhead. The noise in the cockpit was deafening, rendering communication between the pilots extremely difficult, and internal damage to the engines caused smoke to enter the cockpit and cabin through the bleed air and air conditioning systems. The emergency caught both pilots by surprise. There was confusion and shock on the flight deck, a situation compounded by the extremely loud noise from the overspeeding propellers. About four seconds after the double propeller overspeed began, the beta warning horn started to sound intermittently, although the pilots stated afterwards they did not hear it. The left propeller RPM reduced to 900 RPM (in the governing range) after about 10 seconds. It remained in the governing range for about 5 seconds before overspeeding again for about 15 seconds, then returned to the governing range. During this second overspeed of the left propeller, the left engine high speed compressor increased above 110 % NH, becoming severely damaged in the process. About 3 seconds after the left propeller began overspeeding for the second time, the right propeller went into uncommanded feather due to a propeller control unit (PCU) beta switch malfunction, while the right engine was still running at flight idle (75% NH). Nine seconds after the double propeller overspeed event began, the Pilot-in-command shouted to the First Officer „what have we done?‟ The First Officer replied there had been a double propeller overspeed. The Pilot-in-command then shouted a second and third time „what have we done?‟. The First Officer repeated that there was a double propeller overspeed and said that the right engine had shut down. The Pilot-in-Command shouted that he could not hear the First Officer, who – just as the left propeller began governing again and the overspeed noise subsided – repeated that the right engine had shut down and asked if the left engine was still working. The Pilot-in-command replied that it was not working. Both pilots then agreed that they had „nothing‟. At this point, about 40 seconds after the propeller overspeed event began, the left propeller was windmilling and the left engine was no longer producing any power because of the damage caused to it by the overspeed. The right engine was operating at flight idle, although the propeller could not be unfeathered and therefore could not produce any thrust. On the order of the Pilot-in-Command, the First Officer made a mayday call to Madang Tower and gave the aircraft's GPS position; he remained in a radio exchange with Madang Tower for 63 seconds. The flight crew did not conduct emergency checklists and procedures. Instead, their attention turned to where they were going to make a forced landing. The aircraft descended at a high rate of descent, with the windmilling left propeller creating extra drag. The asymmetry between the windmilling left propeller and the feathered right propeller made the aircraft difficult to control. The average rate of descent between the onset of the emergency and arrival at the crash site was 2,500 ft per minute and at one point exceeded 6,000 ft per minute, and the VMO overspeed warning sounded again. During his long radio exchange with Madang Tower, the First Officer had said that they would ditch the aircraft, although, after a brief discussion, the Pilot-in-command subsequently decided to make a forced landing in the mouth of the Guabe River. The First Officer asked the Pilot-in-command if he should shut both engines down and the Pilot-in-command replied that he should shut „everything‟ down. Approximately 800 feet above ground level and 72 seconds before impact, the left propeller was feathered and both engines were shut down. The Pilot-in-Command reported afterwards that he ultimately decided to land beside the river instead of in the river bed because the river bed contained large boulders. The area chosen beside the river bed also contained boulders beneath the vegetation, but they were not readily visible from the air. He recalled afterwards that he overshot the area he had originally been aiming for. The aircraft impacted terrain at 114 knots with the flaps and the landing gear retracted. The Flight Attendant, who was facing the rear of the aircraft, reported that the tail impacted first. During the impact sequence, the left wing and tail became detached. The wreckage came to rest 300 metres from the initial impact point and was consumed by a fuel-fed fire. The front of the aircraft fractured behind the cockpit and rotated through 180 degrees, so that it was inverted when it came to rest. Of the 32 occupants of the aircraft only the two pilots, the flight attendant, and one passenger survived by escaping from the wreckage before it was destroyed by fire.
Probable cause:
From the evidence available, the following findings are made with respect to the double propeller overspeed 35 km south south east of Madang on 13 October 2011 involving a Bombardier Inc. DHC-8-103 aircraft, registered P2-MCJ. They should not be read as apportioning blame or liability to any organisation or individual.
Contributing safety factors:
- The Pilot-in-Command moved the power levers rearwards below the flight idle gate shortly after the VMO overspeed warning sounded. This means that the release triggers were lifted during the throttle movement.
- The power levers were moved further behind the flight idle gate leading to ground beta operation in flight, loss of propeller speed control, double propeller overspeed, and loss of usable forward thrust, necessitating an off-field landing.
- A significant number of DHC-8-100, -200, and -300 series aircraft worldwide did not have a means of preventing movement of the power levers below the flight idle gate in flight, or a means to prevent such movement resulting in a loss of propeller speed control.
Other safety factors:
- Prior to the VMO overspeed warning, the Pilot-in-Command allowed the rate of descent to increase to 4,200 ft per minute and the airspeed to increase to VMO.
- The beta warning horn malfunctioned and did not sound immediately when one or both of the flight idle gate release triggers were lifted. When the beta warning horn did sound, it did so intermittently and only after the double propeller overspeed had commenced. The sound of the beta warning horn was masked by the noise of the propeller overspeeds.
- There was an uncommanded feathering of the right propeller after the overspeed commenced due to a malfunction within the propeller control beta backup system during the initial stages of the propeller overspeed.
- The right propeller control unit (PCU) fitted to MCJ was last overhauled at an approved overhaul facility which had a quality escape issue involving incorrect application of beta switch reassembly procedures, after a service bulletin modification. The quality escape led to an uncommanded feather incident in an aircraft in the United States due to a beta switch which stuck closed.
- Due to the quality escape, numerous PCU‟s were recalled by the overhaul facility for rectification. The right PCU fitted to MCJ was identified as one of the units that may have been affected by the quality escape and would have been subject to recall had it still been in service.
The FDR data indicated that the right PCU fitted to MCJ had an uncommanded feather, most likely due to a beta switch stuck in the closed position, induced by the propeller overspeed. It was not possible to confirm if the overhaul facility quality escape issue contributed to the beta switch sticking closed, because the PCU was destroyed by the post-impact fire.
- The landing gear and flaps remained retracted during the off-field landing. This led to a higher landing speed than could have been achieved if the gear and flaps had been extended, and increased the impact forces on the airframe and its occupants.
- No DHC-8 emergency procedures or checklists were used by the flight crew after the emergency began.
- The left propeller was not feathered by the flight crew after the engine failed.
- The investigation identified several occurrences where a DHC-8 pilot inadvertently moved one or both power levers behind the flight idle gate in flight, leading to a loss of propeller speed control. Collectively, those events indicated a systemic design issue with the integration of the propeller control system and the aircraft.
Other key findings:
- The flaps and landing gear were available for use after the propeller overspeeds and the engine damage had occurred.
- There was no regulatory requirement to fit the beta lockout system to any DHC-8 aircraft outside the USA at the time of the accident.
- The autopilot could not be used during the accident flight.
- The operator's checking and training system did not require the flight crew to have demonstrated the propeller overspeed emergency procedure in the simulator.
- After the accident, the aircraft manufacturer identified a problem in the beta warning horn system that may have led to failures not being identified during regular and periodic tests of the system.
Final Report: