What happened
On 21 February 2007, a Boeing 737-30 and registered PK-KKV, operated by PT. Adam SkyConnection Airlines, was performing a scheduled flight from Jakarta to Surabaya. During the final approach to runway 28, the aircraft encountered thunderstorm and rain conditions. As the aircraft descended, the flight crew engaged in non-essential conversation regarding company policies, which lasted until approximately 2,000 feet.
As the aircraft approached the threshold, the rate of descent increased significantly. The cockpit voice recorder captured Ground Proximity Warning System (GPWS) alerts for "Sink Rate" and "Pull Up." Despite these warnings, the aircraft touched down with a vertical acceleration of 5G. The impact was so severe that the right wheel track drifted 4 meters outside the runway shoulder. The force of the landing caused the aft section of the fuselage, starting from passenger row 16, to buckle and the keel beam to break. While there were two minor injuries among the 155 people on board, the aircraft sustained extensive structural damage.
The investigation
The investigation focused on the flight crew's adherence to stabilized approach criteria and cockpit resource management. Investigators analyzed the Digital Flight Data Recorder (DFDR) and Cockpit Voice Recorder (CVR), noting that the crew did not perform standard approach briefings or checklist readings. The investigation also examined the aircraft's physical state, finding significant deformation in the wheel well, a broken nose landing gear wheel hub, and bottoming marks on both main landing gear shock struts, indicating an excessive impact load.
Findings
- The aircraft was in an unstable approach characterized by an excessive sink rate and improper pitch attitude.
- The flight crew failed to respond to critical GPWS alerts and did not initiate a go-around procedure.
- Non-essential cockpit communication distracted the crew from essential flight tasks and procedures.
- Landing flaps were selected too late, at an altitude below 1,000 feet.
- The high vertical acceleration during touchdown caused the structural failure of the keel beam and fuselage buckling.
Safety action
- The Directorate General Civil Aviation is advised to enhance safety oversight regarding operator training.
- It is recommended that operators strictly enforce cockpit procedures, including approach briefings, checklist usage, and a silent cockpit policy during critical phases of flight.