What happened
On August 16, 2010, at 01:47 local time, an Boeing 737-700, registration HK-4682, was performing a non-precision approach to Runway 06 at Gustavo Rojas Pinilla International Airport in San Andrés, Colombia. The aircraft, operated by Aerovías de Integrante Regional S.A. (Aires S.A.), was flying under Instrument Flight Rules (IFR) amidst severe weather conditions, including heavy rain and thunderstorms.
During the approach, the aircraft impacted the terrain approximately 49 meters before the runway threshold, striking a depression roughly two meters below the runway level. The impact initiated a sequence of destruction that caused the fuselage to break into three parts. The aircraft eventually came to a stop 120 meters past the threshold. All 125 passengers and 6 crew members sustained injuries ranging from minor to serious. Following the impact, a small fire broke out, which was extinguished by the airport's emergency services.
The investigation
The Colombian Civil Aviation Authority (Aerocivil) launched an investigation involving specialists in human factors, maintenance, meteorology, and operations. The investigation was supported by representatives from the NTSB, Boeing, and General Electric.
Investigators examined the flight data recorder (FDR) and cockpit voice recorder (CVR) to reconstruct the final moments of the flight. The analysis focused on the crew's performance during the approach, the impact of the heavy rain and nighttime conditions, and the effectiveness of the visual approach aids, such as the PAPI lights. The investigation also reviewed the transition of crew members from turboprop to jet aircraft operations and the meteorological information provided by air traffic control.
Findings
- The primary cause of the accident was the execution of the flight below the proper approach angle.
- The crew experienced a "black hole" illusion, a phenomenon where a nighttime approach to a runway surrounded by low-contrast terrain and intense localized lighting leads the crew to believe they are at a much higher altitude than they actually are.
- Adverse meteorological conditions, specifically heavy rain, significantly degraded visibility and exacerbated the visual illusion.
- There was a discrepancy in the crew's perception of their glide path due to the lack of visual references and the specific lighting environment of the airfield.