By Simon Hradecky, created Monday, Apr 4th 2016 14:54Z, last updated Monday, Apr 10th 2017 13:56Z A Batik Air Boeing 737-800, registration PK-LBS performing flight ID-7703 from Jakarta Halim Perdanakusuma to Ujung Padang (Indonesia) with 49 passengers and 7 crew, was in the takeoff roll on runway 24 at 19:55L (12:55Z) when its left wing tip entangled with the vertical tail and left wing of a Transnusa Avions de Transport Regional ATR-42-600 registration PK-TNJ crossing the runway under tow and separated the most of the vertical tail plane as well as the left wing from the ATR, the left wing tank ruptured open. Both aircraft caught fire, the Boeing was evacuated via slides. Fire engines responded and were able to put the fires out in a matter of minutes. There were no injuries, both aircraft received substantial damage.



Indonesia's Ministry of Transport reported the Boeing was taxiing for departure, the ATR was under tow to a hangar when the aircraft collided causing damage to the left wing tip of the Boeing and separation of vertical tail and left wing of the ATR. There were no injuries. The airport needed to be closed however.



Ground observers reported the Boeing 737-800 was already accelerating for takeoff from runway 24, when the ATR under tow crossed the runway about 1280 meters/4200 feet down the runway. The Boeing rejected takeoff but could not stop in time to avoid the collision.



Radar data suggest the Boeing was accelerating for takeoff from runway 24 reaching about 110 knots over ground when takeoff was rejected. The aircraft came to a stop about 500 meters/1650 feet past the intersection of the runway with the only crossing taxiway.



Batik Air reported their flight was cleared for takeoff and was accelerating when the aircraft under tow crossed the runway. Their crew rejected takeoff however could not avoid the collision.



Indonesia's NTSC have opened an investigation into the accident.



On Apr 5th 2016 Lembaga Penyelenggara Pelayanan Navigasi Penerbangan Indonesia (LPPNPI), ATC provider, reported that the tower controller on duty, his assistant as well as the supervisor were relieved from duties for at least three weeks because of emotional disorders and psychological effects of the accident on them. Indonesia's NTSC in the meantime is collecting data and is going to investigate the accident.



On Apr 6th 2016 Indonesia's Ministry of Transport suspended all ground handling operations by Jasa Angkasa Semesta (JAS) at Halim Perdanakusuma Airport arguing that the ground handler failed to prevent the collision on the runway. The suspension, not affecting JAS operations on other Indonesian airports, remains in effect until JAS complies with NTSC recommendations.



On Apr 11th 2016 Indonesia's NTSC released two safety recommendations to Indonesia's Ministry of Transport as result of the investigation so far: all aircraft operating within the runway area, irrespective of being powered, towed or otherwise, should be on the same frequency and all aircraft operating within the runway area, irrespective of being powered, towed or otherwise, should activate their position lights.



On Apr 14th 2016 the French BEA reported based on preliminary information from NTSC Indonesia, that the Batik Boeing 737-800 had been cleared to enter runway 24 via taxiway C and backtrack the runway. In the meantime the tug driver of the Transnusa ATR requested clearance to cross the runway from the north to the south apron and received clearance to taxi via taxiway C, runway 06/24 and taxiway G. While crossing the runway the tug driver saw the Boeing 737 accelerate for takeoff and attempted to steer the tug and aircraft to the right runway shoulder, however the left wing of the Boeing collided with the vertical stabilizer and left wing of the ATR. The Boeing rejected takeoff and came to a stop 400 meters past the point of collision. The occurrence was rated an accident and is being investigated by Indonesia's NTSC.



On May 11th 2016 Indonesia's NTSC released their preliminary report reporting, that the AT42 was being towed with two engineers on the flight deck (to apply brakes if needed during the tow) and the tow driver driving the tug, the systems on board of the AT42 were not (electrically) powered up, therefore neither navigation nor strobe lights nor radios for communication were up. Communication between tug driver and ATC was performed via a handheld radio on frequency 152.700MHz (not a frequency available on flight decks).



The airport's tower was staffed by controller, assistant, supervisor and flight data officer. The NTSC annotated that the view to the runway 24 was difficult due to light reflections from the illuminated tower cab.



The controllers reported not seeing any light except on the tug for the AT42.



The B738, communicating on tower frequency 118.600MHz, was cleared to backtrack runway 24.



The tug driver, towing the AT42 from the north apron to the south apron, was told to report on taxiway C, shortly after reported on taxiway C and was instructed to expedite the taxi by the assistant. The tug driver stated the taxiroute was via taxiway G which was affirmed by the assistant (editorial note: the report suggests that this exchange was taken as clearance to enter the runway by the tug driver although strictly formally a clearance to enter the runway had not been issued and the assistant obviously did not assume the AT42 would continue onto the runway, realizing this only after the collision when inquiring with the tug driver).



The B738 was still backracking runway 24. Some time later the B738 performed the 180 and reported ready for takeoff. The controller checked the runway for any obstacles, did not see any vehicles or object on the runway and cleared the flight for takeoff.



The NTSC then described the events:



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 lineup at the turn pad beyond the threshold runway 24.



After received the takeoff clearance, the Second in Command (SIC) as pilot flying (PF) opened the power and pressed the Take Off / Go Around (TOGA) button.



The towing car driver stated that when he saw the ID 7703 was lining up for takeoff then asked to the Halim Tower whether the ID 7703 was initiating the takeoff, and there was no reply from the Halim Tower. The towing car driver then speeds up the towing and turned to the right side of the runway.



When ID 7703 was on rolling takeoff at approximate 80 knots, the SIC saw an object and confirming to the Pilot in Command (PIC) concerning to the object. The pilots could not identify the object but later on when the object became closer, the SIC realized that there was an aircraft.



The PIC took over control and applied the right rudder towards the right side of runway centerline and maintained between the runway centerline and the runway edge. The PIC intended to reject the takeoff shortly after the pilot felt an impact. The pilot performed the reject takeoff and the ID 7703 stopped at approximately 400 meter from the towed aircraft which stopped at the left of the runway 24 centerline at approximately 100 meters from taxiway G.



The assistant saw fire on the left side of ID 7703 when the aircraft rolled between taxiway C and B. Then the assistant pressed the crash bell and informed Rescue and Fire Fighting Service (RFFS) about the fire.



After the aircraft stopped, the PIC commanded to the SIC to perform ON GROUND EMERGENCY procedure, and commanded to the flight attendant ATTENTION CREW ON STATION twice. The PIC noticed fire on the left wing tip and immediately shut down both engines, activated the fire extinguishers of both engines and Auxiliary Power Unit (APU) and commanded to the flight attendant evacuation from the right.



After the aircraft stopped and received the PIC command ATTENTION CREW ON STATION, the flight attendants checked the condition inside and outside the aircraft through the viewing window. There was no damage inside the aircraft and they did not see any fire outside the aircraft.



The flight attendants opened all aircraft passenger doors and the escape slides deployed. Most of passengers were evacuated from the left forward door (1L).



The pilots realized that the impacted object was a towing aircraft after they disembarked the aircraft.



The air traffic controller set crew realized that the towed aircraft was on the runway and collided with ID 7703 after asked to the towing car driver.



The left wing of the Boeing 737 struck the AT-42 about 850 meters down runway 24, the Boeing came to a stop about 400 meters further down the runway. The data stored by the flight data recorder suggest that the power levers were retarded after the collision and the autobrakes engaged at the same time, the speed increased by 14 knots between collision and engagement of autobrakes. Takeoff was rejected at about 130 KIAS.



On Apr 10th 2017 Indonesia's NTSC (KNKT) released their final report concluding the probable causes of the accident were:



- Handling of two movements in the same area with different controllers on separate frequencies without proper coordination resulted in the lack of awareness to the controllers, pilots and towing car driver.



- The communication misunderstanding of the instruction to follow ID 7703 most likely contributed the towed aircraft enter the runway.



- The lighting environments in the tower cab and turning pad area of runway 24 might have diminished the capability to the controllers and pilots to recognize the towed aircraft that was installed with insufficient lightings.



The NTSC reported the communication with respect to the tow driver:



On parking stand B-1:



The towing car driver requested to Halim Control Tower Unit (Halim Tower) for towing to reposition an aircraft from parking stand B-1 to the south apron and was replied by the Flight Data Officer to standby. After the ID7703 started to taxi, the assistant controller issued towing clearance to the towing car driver and to report when on taxiway C.



At about abeam parking stand B-9:



The assistant controller instructed the towing car driver to expedite the towing and to follow ID 7703. The instruction was acknowledged by the towing aircraft driver.



At about entering taxiway C:



The assistant controller reinstructed the towing car driver to expedite the towing and to follow ID 7703. The instruction was acknowledged by the towing aircraft driver.



Note: The air traffic control crew on duty stated that this communication did not occur.



On taxiway C:



The assistant controller reinstructed the towing car driver to expedite the towing and to follow ID 7703. The towing car driver confirmed that the taxi route was via taxiway G and affirmed by the assistant controller.



Note: The air traffic control crew on duty stated that this communication did not occur.



On the runway:



The towing car driver asked twice to the Halim Tower unit whether the ID 7703 was initiating the takeoff and there was no reply.



Note: The air traffic control crew on duty stated that this communication did not occur.



After the collision:



The assistant controller requested the towed aircraft position. The towing car driver informed that the towed aircraft was on the runway and had just collided with ID 7703.



The NTSC analysed with respect to the tow driver:



The instruction to follow the ID 7703 was given when the assistant controller did not maintain the continuous watch to the towed aircraft position and expected that the towing car driver would report when position on taxiway C. Meanwhile the towing car driver might interpret that the towed aircraft approved to enter the runway and considered the position report on taxiway C was no longer required. This communication misunderstanding most likely contributed the towed aircraft enter the runway.



The NTSC analysed with respect to the tower controller:



The lighting environment in the tower cab created glare on the window glass which increased the difficulty for the controllers to observe the towed aircraft that was not clearly visible, especially from the rear.



With respect to the collision avoidance maneouvers attempted the NTSC analysed:



During the takeoff roll, after the ID 7703 pilots noticed an object on the runway. At a speed of approximately 115 knots, the rudder and steering was deflected and the aircraft heading changed approximately 2 degrees to the right for about 2 seconds. This was the pilots action to deviate and maintain the aircraft position between the runway centerline and the runway edge. The pilot tried to avoid collision with the object and to stay on the runway. This action made the aircraft deviate approximately 6 meters to the right from the runway centerline.



The towing car driver saw that the ID 7703 was on the takeoff roll, then accelerated the towing and turned to the right side of the runway. The investigation found that the towing car was on the grass after the impact and the aircraft was on a heading of approximately 080 degrees.



Both aircraft had moved away from the runway centerline, however the ID 7703 left wing collided with the left wing and the vertical stabilizer of the towed aircraft.



The decision of both the pilot and the towing car driver to move away from the runway centerline avoided a centerline (head to head) collision however the wing collision was unavoidable. The wing collision was less severe compared to an aircraft collision on the runway centerline.



Metars (no later METARs available):

WIHH 041200Z 04006KT 5000 HZ FEW017CB SCT018 30/25 Q1010 RMK CB TO SW

WIHH 041100Z 04008KT 6000 SCT018 31/24 Q1008 NOSIG

WIHH 041000Z 06012KT 7000 FEW018 32/23 Q1007 NOSIG

WIHH 040900Z 06012KT 7000 FEW018 33/24 Q1007 NOSIG

WIHH 040800Z 06010KT 7000 SCT018 33/24 Q1007 NOSIG



The aftermath and emergency response (Video: Ippi Thyssen):

https://www.youtube.com/watch?v=vQZ98Dhf_No



View from cockpit while aligning with runway 24 of a flight departing Halim runway 24 just before the collision (Photo: NTSC):





Wreckage distribution (Graphics: NTSC):





The collision and fire damage of PK-TNJ (Photo: TunasKelapa):





The collision and fire damage of PK-LBS (Photo: TunasKelapa):





Map (Graphics: AVH/Google Earth):







