A preliminary report into a take-off collision at Jakarta’s Halim Perdanakusuma airport on 4 April shows that the flight crew of a Batik Air Boeing 737-800 had been cleared for take-off as another aircraft was being towed on the runway.

The report, released by Indonesia's National Transport Safety Committee, also shows that the Batik Boeing 737-800 (registered as PK-LBS), was communicating with the Halim tower control using a different frequency from the tow car which was moving a TransNusa Air Services ATR 42-600 (PK-TNJ). The turboprop was being towed with its navigation lights, strobe lights and radio communication off, and the tow car driver communicating with the control tower using a handheld radio.

The driver had requested to tow the turboprop from the north apron to the south apron, which required crossing runway 06/24. The 737 meanwhile was preparing for a flight to Makassar, with 56 people on board.

Halim Perdanakusuma International airport layout

halim layout

Indonesia Directorate General of Civil Aviation

AT 12:45 UTC, the pilot of the 737 received push back clearance from parking stand B-2 . Shortly after, the tow car driver was instructed to follow the 737 and report when on taxiway C. The tow car has to cross the runway onto taxiway G to reach the south apron, while the 737 needed to get on runway 24 via taxiway C.

At 12:53 UTC, the 737 received clearance to enter and backtrack runway 24. The tow car driver said that when the towed aircraft was on taxiway C, he was instructed to expedite the tow, and even clarified that the taxi route was via taxiway G. Several times, he was also told to “expedite the tow and follow” the 737, says the report.

At 12:56 UTC, the 737 pilot reported ready for takeoff, and was cleared by the controller, who did not see any vehicles or objects on the runway. The narrowbody pilot also commented that during line up, the lights surrounding the turn pad were "very bright" and affected his forward vision for a "short time".

The tow driver meanwhile, said that upon seeing the 737 lining up for take-off, he asked the control tower if the aircraft was initiating the take-off but did not receive a reply. He then sped up the towing and “turned to the right side of the runway”.

The avoiding manoeuvre however could not prevent the collision, and the 737's left wing-tip struck the vertical fin of the ATR, as well as its left wing. The 737 crew aborted the take-off and came to a halt on the runway about 400m from the point of impact.

Both aircraft were badly damaged in the accident, although no one on board was injured.

The NTSC has since recommended that AirNav Indonesia require all towing aircraft to have their navigation lights on, and to communicate on published tower frequency. Controllers should also record towing movements on the flight progress strip.

Source: Cirium Dashboard