Flight

The following findings were identified:
1. The aircraft had valid Certificate of Airworthiness prior to the accident and was operated within the weight and balance envelope.
2. Both pilots had valid licenses and medical certificates.
3. The accident flight from Masamba (WAFM) to Makassar (WAAA) was the 6th sector for the aircraft and the crew that day. The PIC acted as Pilot Flying and the
SIC acted as Pilot Monitoring.
4. The satellite image published by BMKG at 0700 UTC showed that there were cloud formations at the accident area. The local villagers stated that the weather
on the accident area was cloudy at the time of the accident.
5. The aircraft departed Masamba at 0625 UTC (1425 LT), conducted under VFR with cruising altitude of 8,000 feet and estimated time of arrival Makassar at 0739 UTC.
6. After reached cruising altitude, at about 22 Nm from Masamba, the flight deviated from the operator visual route and directed to BARRU on heading 200° toward the area with high terrain and cloud formation based on the BMKG satellite image
7. The pilots decision making process did not show any evidence that they were concerned to the environment conditions ahead which had more risks and required correct flight judgment.
8. The CVR did not record EGPWS aural caution and warning prior to the impact. The investigation could not determine the reason of the absence of the EGPWS.
9. The CVR data and cut on the trees indicated that the aircraft was on straight and level flight and there was no indication of avoid action by climb or turn.
10. The SAR Agency did not receive any crashed signal from the aircraft ELT most likely due to the ELT antenna detached during the impact.
11. Regarding to the operation of the EGPWS for the flight crew, a special briefing was performed however there was no special training.
12. The operational test of TAWS system was not included in the pilot checklist.
13. The investigation could not determine the installation and the last revision of TAWS terrain database.
14. The investigation could not find the functional test result document after the installation of the TAWS.
15. Some of the DHC-6 pilots have not been briefed for the operation of the TAWS and EGPWS.

Contributing Factors:
Deviation from the company visual route without properly considering the elevated risks of cruising altitude lower than the highest terrain and instrument meteorological condition in addition with the absence of the EGPWS warning resulted in the omission of avoidance actions.

The root cause of the accident is the entry of the aircraft into the cloud at a low altitude, in conditions of increased cloudiness, which led to the impact of the aircraft in the ground. The accident is caused by inadequate preparation of the crew for the flight, deviation of the crew from the planned and approved route by location (diversion from the given route) and flight height (flight at a lower altitude than the approved one), as well as not taking timely procedures to return to the given route and flight height, as well as incorrect actions in case of encountering a deteriorated weather situation on the route under VFR flight conditions.
The accident was affected by:
a) The decision of the manager on the manner of execution of the flight,
b) Ignoring information about the meteorological situation and weather forecast,
c) Inadequate preparation of the crew for the execution of the flight at a low altitude and in conditions of fire of the meteorological situation,
d) Non-compliance with VFR rules for minimum flight height and meteorological minimum for airspace class “F” and “G”,
e) Loss of visual contact with the ground.

The crash of An-2 RA-35141 aircraft occurred during the emergency landing on a forest firebreak. The landing was urged due to in-flight engine power loss as a result of the destruction of the 62.06.02 bronze hub pouring of the master rod big end of the crank mechanism. Most probably the destruction of the bronze hub pouring was caused by a manufacturing flaw consisting in a lack of bronze friction with the steel base on a part of its surface.

The accident was the consequence of a controlled flight into terrain after the crew decided to continue the flight at low height in IMC conditions.
The following contributing factors were identified:
- The foreign crew was not familiarized with the area of flight,
- Poor flight planning,
- CFIT.

The collision was the consequence of an error on part of the crew of the BAe 125 who failed to follow his assigned altitude at FL340 and continued to FL350 which was the assigned altitude for the Boeing 737. The captain of the B737 confirmed that he have seen the aircraft descending to him. Only the flight recorders could have helped to determine how such a situation could have occurred; Unfortunately they disappeared with the plane. There was a difference of 1,000 feet in the indications of both captain/copilot altimeters.

Findings as to causes and contributing factors:
1. The pilot performed manoeuvres with a reduced safety margin at low altitudes. As a result, these flights involved a level of risk that was unnecessary to attain the objectives of sightseeing flights.
2. With no restrictions on manoeuvres and no minimum altitude prescribed by the company prior to flight, the pilot flew according to his own limits and made a steep turn at approximately 110 feet above ground level.
3. When the pilot made a steep left turn, aerodynamic stalling ensued, causing an incipient spin at an altitude insufficient to allow control of the aircraft to be regained prior to vertical collision with the terrain.
4. The absence of an angle-of-attack indicator system and an impending stall warning device deprived the pilot of the last line of defence against loss of control of the aircraft.

Findings as to risk:
1. If lightweight flight data recording systems are not used to closely monitor flight operations, there is a risk that pilots will deviate from established procedures and limits, thereby reducing safety margins.
2. If Transport Canada does not take concrete measures to facilitate the use of lightweight flight data recording systems and flight data monitoring, operators may not be able to proactively identify safety deficiencies before they cause an accident.
3. If pilots do not obtain at least the regulatory rest periods, there is a risk that flights will be conducted when pilots are fatigued.
4. Unless all flights made are recorded in the pilot’s logbook and monitored by the company, it is possible that the pilot will not receive the required rest periods, which increases the risk of flights being conducted when the pilot is fatigued.
5. If flights made are not recorded in the aircraft’s journey logbook, it is possible that inspection and maintenance schedules and component lifetimes will be exceeded, increasing the risk of failure.
6. Unless safety management systems are required, assessed, and monitored by Transport Canada in order to ensure continual improvement, there is an increased risk that companies will not be able to identify and effectively mitigate the hazards involved in their operations.
7. If pilots do not receive stall training that demonstrates the aircraft’s actual behaviour in a steep turn under power, there is a high risk of loss of control.

Other findings:
1. The replacement of the ventral fin with Seafins on C-FKRJ was in compliance with the requirements of Kenmore Air Harbor Inc.’s supplemental type certificate.
2. The control wheel was in the left-hand position (pilot side) at the moment of impact.
3. Angle-of-attack indicator systems have been recognized as contributing to flight safety by improving pilot awareness of the stall margin at all times, thereby allowing pilots to react in order to prevent loss of control of the aircraft.
4. Stall warning systems have been recognized as a means of improving flight safety by providing a clear, unambiguous warning of an impending stall.

The main cause of the in-flight collision was a poor flight management on part of the OM-ODQ captain.
Contributing factors:
- The captain of OM-ODQ was using a mobile phone at the time of the collision,
- The total weight of OM-ODQ at the time of the accident was above MTOW.

The main cause of the in-flight collision was a poor flight management on part of the OM-ODQ captain.
Contributing factors:
- The captain of OM-ODQ was using a mobile phone at the time of the collision,
- The total weight of OM-ODQ at the time of the accident was above MTOW.

The following findings were identified:
1. The aircraft had valid Certificate of Airworthiness and was operated within the weight and balance envelope.
2. All crew had valid licenses and medical certificates.
3. The flight plan form was filed with intention to fly under Instrument Flight Rule (IFR), at flight level 155, with route from Sentani to MELAM via airways W66 then to Oksibil. The MORA of W66 between Sentani to MELAM was 18,500 feet.
4. The flight was the 5th flight of the day for the crew with the same aircraft and the second flight on the same route of Sentani to Oksibil.
5. The CVR data revealed that the previous flight from Sentani to Oksibil the flight cruised at altitude of 11,500 feet and the approach was conducted by direct to left base runway 11.
6. The CVR data also revealed that on the accident flight, the flight cruised at altitude 11,500 feet and intended to direct left base leg runway 11 which was deviate from the operator visual guidance approach that described the procedure to fly overhead the airport prior to approach to runway 11.
7. The witness stated that most of the time, the flight crew deviated from the operator visual approach guidance. The deviation did not identify by the aircraft operator.
8. The downloading process to retrieve data from the FDR was unsuccessful due to the damage of the FDR unit that most likely did not record data during the accident flight. The repetition problems of the FDR unit showed that the aircraft operator surveillance to the repair station was not effective.
9. The CVR did not record any crew briefing, checklist reading and EGPWS altitude callout prior to land on two previous flights nor the EGPWS caution and warning prior to impact.
10. The spectrum analysis of the CVR determined that both engines were operating prior to the impact.
11. Several pilots, had behavior of pulling the EGPWS CB to eliminate the nuisance of EGPWS warning. The pilots stated that the reason for pulling the EGPWS CB was due to the pilots considered this warning activation was not appropriate for the flight conditions. The correction to this behavior was not performed prior to the accident.
12. The investigation could not determine the actual EGPWS CB position during the accident flight.
13. The installation of EGPWS by the aircraft operator was not conducted according to the Service Bulletin issued by the aircraft manufacturer.
14. The terrain data base installed in the EGPWS of PK-YRN was the version MK_VIII_Worldwide_Ver_471 that was released in 2014. The Oksibil Airport was not included in the high-resolution update in this version of terrain database.
15. The information for Oksibil published in AIP volume IV (Aerodrome for Light Aircraft/ALA) did not include approach guidance. The operator issued visual guidance of circling approach runway 11 for internal use.
16. The visual approach guidance chart stated that the minimum safe altitude was 8,000 feet while the aircraft impacted with terrain at approximately 8,300 feet. This indicated an incorrect information in the chart. The investigation considered that the pattern on the approach guidance chart was not easy to fly, as many altitudes and heading changes.
17. Several maintenance records such as component status installed on the aircraft and installation of EGPWS was not well documented. This indicated that the maintenance management was not well performed.
18. The investigation could not find any regulation that describes the pilot training requirement for any addition or modification of aircraft system which affect to the aircraft operation.
19. There was no information related to the status of ZX NDB published on NOTAM prior to the accident.
20. Several safety issues indicated that the organization oversight of the aircraft operator by the regulator was not well implemented.
Contributing Factors:
1. The deviation from the visual approach guidance in visual flight rules without considering the weather and terrain condition, with no or limited visual reference to the terrain resulted in the aircraft flew to terrain.
2. The absence of EGPWS warning to alert the crew of the immediate hazardous situation led to the crew did not aware of the situation.