Dirgantara Air Service Flight 3130

Dirgantara Air Service Flight 3130 (DIR3130/AW3130) was a scheduled domestic passenger flight operated by Dirgantara Air Service from Datah Dawai Airport, Malinau Regency, East Kalimantan to its provincial capital's airport, Samarinda Temindung Airport, Samarinda, East Kalimantan. On 18 November 2000, the aircraft conducting the flight, a Britten Norman Islander BN-2 sheared tree tops and crashed onto the forest near the airport shortly after takeoff. Search and rescue team immediately found the wreckage of Flight 3130 and the survivors. No one was killed in the crash, but all 18 people on board were injured in the crash; 11 of them were seriously hurt.

The final report, published by the National Transportation Safety Committee, concluded that the crash was caused due to multiple factors, which were pilot error, overloading, and lack of safety in the airport (bribery). The wrong perception by the pilot, added with the plane overloading that was caused by bribery, subsequently causing the plane to crash. The airline ceased operations in 2009 and officially went bankrupt in 2013.

Background

The aircraft involved in the crash was a Britten Norman Islander BN-2, registered in Indonesia as PK-VIY. Manufactured in 1981 in United Kingdom, it had accrued a total cycle of 22,336 hours. It had one crew seat and a total of 9 passenger seats. It had an airworthiness certificate published on 27 September 2000. All passengers and crew on board were Indonesian citizen. The one and only crew, Captain Abdul Hayi, had accrued a total flying hours of 7,560.

The aerodrome is owned by the local government and used for pioneer flight operations. The coordinates are 00 47 North, 114 34 East. The elevation is not officially published, only measured from the aircraft altimeter, which is about 650 ft above sea level. The runway designation is 02 and 20. The length of the runway is 750 meter with width of 23 meter. A stopway of 30 meter is provided for runway 02. The runway surface is asphalt and its strength can accommodate up to CASA 212 aircraft. It has an apron, taxiway, but a tower building is not available since the aerodrome is a non-controlled aerodrome. The runway is not equipped with landing direction indicators and, due to local prevailing surface winds at most of the time, the preferred takeoff and landing direction is runway 02. A significant obstacle is the hilly forest in the northerly direction of the extension of runway 02. The first obstacle is about 200 feet high above runway elevation located about 533.3 meters from the end of runway 02, and the second obstacle is about 500 feet above runway elevation 1.262,9 meters from the end of runway 02. Runway slope inclination is 3% from direction of runway 02.

Accident

The Britten Norman Islander took off at 10:51 local time, carrying a total of 17 passengers, including 2 infants and a 5-month-pregnant woman, and 1 crew member on board. Shortly after takeoff, the airport radio operator noticed that the aircraft disappeared behind the forest. The aircraft contacted the first tree and started to veering to the left. It then hit another tree and began zigzagging. The aircraft then contacted the third tree and started to lose control. The landing gear then struck the last contacted tree and then it crashed upside down onto the forest floor. Both wings were ripped off from the fuselage, with fuels leaking from the right wing tip. This created a dangerous post-impact fire risk, as the soil type in Borneo was often flammable.

A search and rescue party was quickly assembled by Datah Dawai Airport authorities shortly after the crash. The wreckage was eventually found 2 kilometers from the airport. All 18 people on board, including 2 infants and a 5-month pregnant woman, were injured with 11 of them were seriously hurt. The crew of the aircraft, identified as Captain Abdul Hayi, had to be transported to Jakarta due to broken legs. The injured were taken to local hospital and the Wahab Sjachrani Civic Hospital in Samarinda. The aircraft was a total loss, with the front section of the aircraft "totally wrecked". The rudder and the vertical stabilizers were found 7 meters from the main wreckage. The fuselage was crushed and bent severely. Passengers and crews initially trapped inside the wreckage. The seats inside the aircraft had to thrown out from the aircraft in order to evacuate the survivors.

Flight sequence analysis

The aircraft performed a takeoff with dual engine operations and rotated at a speed of 70 knots. Based on interviews, the moment the aircraft took off from Datah Dawai, the aircraft seems to not have gained any height, whether from downdraft, engine failure, or both. Noticing that the aircraft didn't gain height, Captain Abdul decided to turn back to the airport and rolled the aircraft to the left in order to avoid high trees. This maneuver, turning back to the airport by veering to the left, was not based on published procedures or visual track charts, as there were not available for departures from runway 02. The investigation also did not find any published information on emergency return-to-base maneuvers. Realizing that the aircraft continued to lose altitude, Captain Abdul prepared for an emergency landing. There was literally no time to conduct a proper emergency procedure, as the aircraft continued to fall with a sharp nose-down pitch.

For a Datah Dawai departure, the first flight segment covers a 1,600 ft range, and the aircraft should have gained 200 ft altitude from runway. The flight, however, did only reach an altitude of 150 ft from the runway elevation at a range of 6.000 ft. This evidence proved that Flight 3130 was overloaded. An interview with Captain Abdul revealed that he had a habit of taking off from Datah Dawai at 70 knots, faster than the aircraft recommended take-off speed of 55–60 knots. He mentioned that doing so would improve his obstacle-clearance performance. The mindset/perception Captain Abdul received is incorrect, as because if the aircraft took off at 70 knots, the time between the aircraft and the obstacles (high ground and trees) became smaller. Because the time between the aircraft and the obstacles became smaller, the aircraft should climb at a higher climb rate. Because it was overloaded, the aircraft did climb, but its speed would decrease. After clearing the obstacle, the aircraft would have lost so much speed that it could no longer gain any height. This combination caused Flight 3130 to stall.