Independent Air Flight 1851 was a chartered flight that operated between the United States and Santa Maria Airport in the Azores. On approach to the airport, the aircraft encountered unforeseen navigational errors that led to its collision with Pico Alto mountain. The event resulted in a tragic loss of life, as all 144 people on board, including passengers and crew, perished in the incident. Eyewitness reports from nearby residents described a loud noise followed by a large fireball, indicating the severity of the crash. Despite the clear weather conditions at the time, the flight failed to maintain its correct altitude and course during its final approach.

The post-incident investigation conducted by aviation authorities raised significant concerns about pilot error, including potential lapses in adherence to standard operating procedures. The flights involved were typically utilized for vacation travel, and many passengers were tourists eager to explore the natural beauty of the Azores, making the tragedy even more poignant. The findings of the investigation shed light on the importance of rigorous training for pilots, particularly regarding approach and landing procedures in unfamiliar terrains.

The crash of Independent Air Flight 1851 stands as a somber reminder of the potential hazards present in aviation, particularly when dealing with mountainous areas and the crucial need for effective communication between pilots and air traffic control. It was a significant incident that necessitated a review of flight safety regulations and highlighted the critical role of navigation technologies and practices in ensuring the security of air travel.