What happened
On the scheduled flight from Bergamo, Italy, to Punta Cana, Dominican Republic, via Santa Maria, Azores, an Boeing 707 operated by Independent Air was cleared by Santa Maria Tower for a runway 19 ILS approach. During the descent clearance, a trainee controller provided an incorrect QNH value that was 9 hPa higher than the actual pressure. Due to communication overlaps between the tower and the flight crew, the full instruction was not properly recorded or acknowledged.
The first officer attempted to read back the clearance but incorrectly understood the descent altitude to be 2,000 feet rather than the instructed 3,000 feet. Inside the cockpit, while the first officer questioned the pressure setting, the captain agreed with the incorrect interpretation. The crew failed to perform a standard approach briefing, which would have identified the minimum safe altitude and the terrain of Pico Alto.
At approximately 14:06, the aircraft began leveling off at 2,000 feet amidst light turbulence. By 14:07, the flight entered heavy clouds at roughly 700 feet AGL. Despite the activation of the GPWS alarm and a whining radio altimeter, there was no corrective action from the crew. At 14:08:12, the aircraft struck a rock wall on a mountain ridge at Pico Alto at an altitude of approximately 1,795 feet AMSL.
Findings
- The primary cause was the crew's failure to follow established operating procedures, specifically regarding the descent below the minimum sector altitude of 3,000 feet.
- An incorrect QNH transmitted by Air Traffic Control resulted in the aircraft being 240 feet lower than indicated on the instruments.
- Communication errors occurred when the first officer interrupted the controller's transmission, leading to an incomplete readback.
- The crew did not conduct a proper approach briefing or review aeronautical charts for terrain hazards.
- There was a lack of appropriate response to GPWS warnings and general lapses in cockpit discipline.
- Contributing factors included inadequate crew training regarding GPWS emergency maneuvers and the use of an unauthorized flight route.