Investigation Summary
The investigation revealed a critical ergonomic and procedural failure. On the Boeing 737 overhead panel, the engine anti-ice switches are located in close proximity to the hydraulic system B pump switches. Approximately 13 minutes before impact, the captain mistakenly flipped the hydraulic switches. While Hydraulic System B was deactivated, Hydraulic System A remained functional, meaning the trailing edge flaps were still available for use. However, the crew failed to recognize that the flaps had not extended despite moving the flap lever. This resulted in an unstabilized approach at speeds significantly higher than normal for the configuration. Compounding the technical error, the crew lost communication with the tower after mistuning the radio frequency and failed to perform the landing checklist, which would have alerted them to the incorrect flap setting. The co-pilot only realized the flaps were at zero degrees 12 seconds before impact, triggered by the stick shaker and EGPWS warnings.
Final Conclusions
The interim report indicates the crash was caused by a chain of human errors including accidental system deactivation, failure to follow standard operating procedures (SOPs), and poor crew resource management. The aircraft was in a non-standard, high-speed configuration for landing, and the crew's late recognition of the state prevented a successful recovery during the go-around.
Photographic Evidence (1)
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Crew Experience
Captain
48-year-old male; also had ATR-72 experience.
First Officer
34-year-old male; pilot flying at the time of the accident.
Systems & Failure Modes
Hydraulic System B
Provides pressure for trailing edge flaps and other flight controls; its accidental deactivation led to the flaps-up configuration.
Engine Anti-Ice
System intended to prevent ice buildup; the proximity of its switches to hydraulic controls led to the initial error.
EGPWS
Enhanced Ground Proximity Warning System provided 'Sink Rate' and 'Pull Up' alerts seconds before impact.
Interesting Facts
- 01The aircraft was a 31-year-old Boeing 737-400SF converted freighter.
- 02The captain was killed, while the co-pilot and two supernumerary crew members (cargo attendants) survived with injuries.
- 03Hydraulic System B deactivation occurred, but trailing edge flaps remained available via System A; however, the crew never extended them.
- 04The crew failed to complete the landing checklist during the approach.
- 05According to news reports, all 13 occupants of the house struck by the aircraft were safely evacuated.
- 06Preliminary investigation found no evidence of sabotage or foul play.
Safety Actions & Advisories
Interim Investigation Findings
The Lithuanian National Safety Investigation Authority released an interim report within 30 days to highlight the human factors and procedural omissions identified in the early stages of the probe.