Investigation Summary
The accident occurred at night under light rain conditions. The TransNusa ATR 42 (PK-TNJ) was being repositioned from the north to the south apron. Because the aircraft was being towed without electrical power, its navigation and strobe lights were off, and its onboard radios were inactive. The towing crew communicated with the Halim Tower assistant controller via a handheld radio on a frequency of 152.7 MHz. Simultaneously, Batik Air Flight 7703 was communicating with the primary controller on 118.6 MHz. The assistant controller instructed the tow crew to follow the Batik Air jet and report at taxiway C. However, a misunderstanding of these instructions led the tow crew to enter the runway. The primary controller, unable to see the unlit ATR 42 against the bright lights of the runway turn pad and hampered by reflections on the tower windows, cleared Flight 7703 for takeoff. As the Boeing 737 accelerated through 80 knots, the crew spotted the obstacle. The Captain applied right rudder to avoid a head-on collision, but the aircraft's left winglet sliced through the ATR's vertical stabilizer and left wing at approximately 130 knots. The Boeing crew successfully rejected the takeoff and evacuated all passengers via slides as a fire broke out on the damaged wing.
Final Conclusions
The Komite Nasional Keselamatan Transportasi (KNKT) concluded that the collision was caused by a breakdown in coordination between air traffic controllers managing two movements on different frequencies. Contributing factors included the lack of lighting on the towed aircraft, the bright environment of the runway turn pad which diminished the pilots' night vision, and reflections on the tower cab glass that prevented controllers from identifying the runway incursion. The investigation report (KNKT.16.04.07.04) was completed within one year.
Photographic Evidence (1)
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Batik Air ID7703 — Boeing 737-8GP (WL) · PK-LBS
TransNusa Aviation Mandiri Towing — ATR 42-600 · PK-TNJ
Systems & Failure Modes
Radio Communication
The use of two different frequencies (118.6 MHz for flight crew and 152.7 MHz for ground tow) prevented the pilots and tow crew from hearing each other's instructions. The tow crew used a handheld radio on 152.7 MHz.
Aircraft Lighting
The ATR 42's navigation and strobe lights were inactive due to the lack of electrical power during the tow, making it nearly invisible to the controllers and the taking-off crew at night.
Runway Turn Pad Lighting
High-intensity lighting around the runway 24 turn pad created glare that affected the pilots' forward vision during line-up, a factor cited by the KNKT.
Interesting Facts
- 01The Boeing 737 was carrying 49 passengers and 7 crew members, totaling 56 occupants.
- 02The ATR 42 movement involved four personnel: two engineers in the cockpit to operate brakes, one towing car driver, and one supporting personnel.
- 03The ATR 42 was unlit because it was being towed without AC electrical power.
- 04The Boeing 737's left wing was severed by approximately 5.75 meters during the impact.
- 05The ATR 42 was damaged beyond repair, losing its entire empennage and left outer wing.
- 06The Boeing 737 (PK-LBS) was eventually repaired and returned to service in September 2016.
Safety Actions & Advisories
ATC Frequency Management
Source ↗AirNav Indonesia was recommended to ensure that all aircraft and vehicle movements on the active runway are managed on a single discrete frequency to maintain situational awareness for all parties.
Tower Visibility Improvements
Source ↗Recommendations were made to improve the lighting environment in the tower cab, including the installation of non-reflective glass or adjusting internal lighting to prevent reflections that obstruct the controllers' view of the runway.
Towing Procedures
Source ↗Procedures were updated to require that any aircraft being towed at night must have functional navigation lights, even if it requires an external power source or battery operation.