On 8 February 1989, the aviation world witnessed a profound tragedy when Independent Air Flight 1851, a Boeing 707, was catastrophically lost. Operating as an American charter flight, this ill-fated journey had departed from Bergamo, Italy, destined for the popular resort destination of Punta Cana in the Dominican Republic. However, its crucial stopover in the Azores, an autonomous region of Portugal, proved fatal. While on approach to Santa Maria Airport (LPAZ/SMI) for a scheduled technical stop, the aircraft tragically struck Pico Alto, a prominent peak on Santa Maria Island. This devastating impact led to the complete destruction of the aircraft and the loss of all 144 individuals on board, marking it as the deadliest plane crash in Portuguese history. The passenger manifest notably comprised Italian citizens, predominantly tourists or vacationers, while the entire flight crew were American nationals, underscoring the international scope of this tragic event. In Italy, this somber incident is widely remembered and referred to as "Il disastro delle Azzorre," or "The disaster of the Azores."

Understanding Independent Air Flight 1851

Independent Air was a United States-based charter airline, operating a fleet that included the venerable Boeing 707. The Boeing 707, a foundational four-engine jet airliner, was a workhorse of long-haul flights and charter operations in that era. Flight 1851’s route from Bergamo’s Orio al Serio Airport (BGY) to Punta Cana International Airport (PUJ) was a typical long-distance charter, necessitating a refuelling stop. Santa Maria Airport, strategically located in the eastern Azores, historically served as a vital transatlantic staging post, making it a common stopover for such extended flights.

The Catastrophic Impact at Pico Alto

The crash occurred on Santa Maria Island, approximately 60 nautical miles from its intended destination, Santa Maria Airport. Pico Alto, reaching an elevation of approximately 1,900 feet (579 meters), presented a significant terrain obstacle. The aircraft, descending during its non-precision VOR/DME approach to runway 18, tragically descended below the minimum safe altitude for the terrain. The impact was immediate and catastrophic, tearing the aircraft apart across the mountainside. The grim outcome was the instantaneous loss of all 137 passengers and 7 crew members, a total of 144 lives, making it an indelible and dark chapter in aviation safety and the most severe air disaster ever to occur on Portuguese territory.

Key Findings from the Investigation

The official investigation, conducted by Portuguese authorities with assistance from the U.S. National Transportation Safety Board (NTSB), concluded that the primary cause of the crash was Controlled Flight Into Terrain (CFIT). This occurs when an airworthy aircraft, under the control of the flight crew, is inadvertently flown into terrain, water, or obstacles. Several critical factors contributed to this tragic outcome:

• Misinterpretation of Altimeter Settings (QNH): The crew miscalculated or misinterpreted the QNH (barometric pressure setting for altimeters) provided by air traffic control, leading them to believe they were at a higher altitude than they actually were. This fundamental error resulted in an uncommanded descent below safe terrain clearance.
• Non-Precision Approach Challenges: The VOR/DME approach to Santa Maria Airport was a non-precision approach, relying heavily on pilot skill and accurate instrument interpretation, particularly in Instrument Meteorological Conditions (IMC) of clouds and rain.
• Crew Coordination and Communication: Deficiencies in Crew Resource Management (CRM) were identified, including inadequate cross-checking of instruments and a lack of assertive challenge from the first officer regarding the captain's altimeter readings and descent profile.
• Fatigue and Workload: While not a direct cause, the long-haul nature of the flight and potential fatigue may have exacerbated decision-making challenges.

Legacy and Aviation Safety Enhancements

The Independent Air Flight 1851 disaster served as a stark reminder of the dangers of CFIT and contributed significantly to advancements in aviation safety. Its lessons resonated globally, leading to:

• Increased emphasis on standardized altimeter setting procedures and robust cross-checking protocols, especially during approaches.
• Enhanced training in Crew Resource Management (CRM) to foster better communication, decision-making, and challenge-and-response within the cockpit.
• Development and wider implementation of Ground Proximity Warning Systems (GPWS) and later Enhanced Ground Proximity Warning Systems (EGPWS), designed to alert crews to dangerously close terrain proximity.
• A renewed focus on the complexities and inherent risks of non-precision approaches, promoting the adoption of more precise approaches where possible.

Frequently Asked Questions About Independent Air Flight 1851

When did Independent Air Flight 1851 crash?

The accident occurred on 8 February 1989.

Where did Independent Air Flight 1851 crash?

The aircraft struck Pico Alto on Santa Maria Island, part of the Azores archipelago in Portugal, during its approach to Santa Maria Airport.

How many people died in the Independent Air Flight 1851 crash?

All 144 people on board – 137 passengers and 7 crew members – perished in the disaster.

Was this the deadliest plane crash in Portugal?

Yes, with 144 fatalities, Independent Air Flight 1851 remains the deadliest aviation accident in Portuguese history.

What was the cause of the Independent Air Flight 1851 crash?

The official investigation determined the primary cause was Controlled Flight Into Terrain (CFIT), primarily due to the crew’s misinterpretation of altimeter settings and descent below minimum safe altitude during a non-precision approach.

Why is it called "The disaster of the Azores"?

This moniker, especially prevalent in Italy ("Il disastro delle Azzorre"), arose because the majority of the passengers were Italian citizens, and the crash occurred in the Portuguese Azores archipelago, making it a significant event for both nations.