What happened
The accident occurred while the aircraft was engaged in a routine pipelining patrol mission. The flight was conducted at an altitude of approximately 1,000 feet above ground level (AGL) through mountainous terrain. During this phase of the operation, the pilot encountered a sudden downdraft windshear. This meteorological event caused the aircraft to enter an uncontrollable descent with a vertical speed of roughly 2,000 feet per minute.
Despite efforts to recover, the pilot was unable to arrest the descent rate. The aircraft subsequently impacted rough terrain and was destroyed by fire following the collision. The pilot sustained minor injuries in the crash but survived the incident.
The investigation
The investigation focused on the immediate environmental conditions and the aircraft's performance during the final moments of flight. Analysis confirmed that the primary factor leading to the loss of control was the encounter with the downdraft windshear while operating at low altitude in complex topography. The structural integrity of the airframe was compromised upon impact with the uneven ground, resulting in a post-crash fire.
Findings
The critical factors identified in this accident include:
- Mountainous terrain limiting recovery options and maneuvering room.
- Downdraft windshear causing an immediate and severe loss of altitude.
- Inability to recover from the high-rate descent before terrain impact.
Safety message
This incident highlights the extreme dangers of low-altitude flight in mountainous regions, particularly when conducting utility or patrol missions. Pilots must remain vigilant for sudden changes in wind patterns and understand the limitations of their aircraft's climb performance when faced with severe downdrafts at low altitudes.