2016 Halim Airport runway collision

Investigation

Minister of Transportation Ignasius Jonan tasked the National Transportation Safety Committee with investigating the cause of the accident. Jonan later criticised Angkasa Pura for the vacuum of power in Halim Perdanakusuma International Airport's management for the preceding two weeks.

President Director of TransNusa Air Services Juvenile Jodjana held a press conference and stated that the tow truck crew had followed the established procedure for towing the ATR-42. The aircraft was due to park at an apron in the south portion of the airport. Batik Air's spokesman also stated that Flight 7703's crew had followed procedures and had been cleared for take-off by Air Traffic Control (ATC). Investigators had retrieved both black boxes from both aircraft and would analyse the content in their facility (the black box from the ATR would probably reveal nothing as AC electrical power would not have been available). They questioned the crew of Flight 7703, and would speak to the air traffic controller that was on duty. NTSC would also interview the ground crew on the tow truck, investigate the taxi procedure, as well as the maintenance of both aircraft.

After analysing the content of the black box, it was revealed that Batik Air had been cleared for take off while the TransNusa Air Services' ATR 42 was still on the runway. The pilots were aware that a collision was inevitable, and tried to steer the plane to avoid a more severe collision. The NTSC later would transcript the CVR and FDR from both black boxes. Owing to a large number of air accident cases in Indonesia, NTSC stated that it would take up to five months to solve the cause of the collision. The ground handling service in Halim Perdanakusuma International Airport were suspended by the government in response to the accident.

Experts believe that the accident may have been caused by weak co-ordination between ATC, the tow truck crew, and Flight 7703's crew and stated that if Flight 7703 was travelling at high speed, the accident could have been similar to the Tenerife airport disaster in 1977.

The flight recorders, both the cockpit voice recorder and the flight data recorder, from the ATR 42, did not provide any data as there was no electrical power at the time of the accident. Therefore, the NTSC could only retrieve the flight recorders from the Boeing 737, which was supported with AC electrical power at the time. The NTSC stated that because the towed ATR 42 did not have electrical power, none of the lights inside and outside the aircraft were on. Radio communication was also off, therefore the ground crew of the towed ATR 42 could only communicate to the Tower through the handheld radio communication.

Flight 7703 was communicating with the tower on frequency 118.6 MHz. The communications were recorded by ground-based, automatic, voice-recording equipment and the CVR with good quality; while the towed ATR 42 was communicating on frequency 152.7 MHz. The communications in the ATR 42 were not recorded. Based on interview of the ground crew, the towed ATR 42 requested for a reposition to the south apron. When Flight 7703 was pushed back, the towed aircraft was instructed by Halim Tower unit to continue towing and report taxiway "C”.The absence of lighting on the ATR 42 made it impossible for the air traffic controller to notice the movement of the aircraft, knowing that it was night, aggravated by light shower in Halim Airport. The assistant controller could only see the lights from the towing vehicle. At this point, the towing car driver stated that he saw Flight 7703 was lining up for takeoff then asked to the Halim Tower whether Flight 7703 was initiating the takeoff, but there was no reply from the Halim Tower. Fearing that Flight 7703 would take off, the towing car driver then speeds up the towing and turned to the right side of the runway.

The pilot stated that during line up, the lights surround the turn pad were very bright and affected his forward vision for a short time. It was common practice in Halim to line-up at the turn pad beyond the threshold runway 24. The air traffic controller then observed if there was another aircraft or a vehicle in the runway. Because they didn't see any other aircraft in the runway, Flight 7703 was then cleared for take off by Halim Tower. While taking off, the First Officer then realised that there was an object in the runway (the ATR 42), the Captain quickly took over the control and applied a right rudder input immediately. The Boeing 737-800's winglet then slammed into the ATR 42, at a speed of 80 kn.

At the conclusion of the investigations it was established that the causes of the accident were:

Lack of coordination between controllers and movements, since flight 7703 and towing were managed by two different controllers and on two different frequencies;

A misunderstanding of the instruction given to the tow to follow flight 7703 after initially reporting to communicate when the tow was on ring C, which likely contributed to the runway incursion as the towing vehicle driver may have interpreted the instruction as new, making communication no longer necessary once reaching the junction;

The lighting in the control tower and the reflections on its windows may have caused the loss of visual contact with the tow, which was poorly lit and difficult to identify; furthermore, the assistant controller coordinated other movements, losing contact with the tow. The high lighting of the turnaround area may have contributed to the accident by preventing the pilots from recognizing the obstacle promptly.