Independent Air Flight 1851
Encyclopedia
In 1989, Independent Air
Independent Air
-Code data:*IATA Code: IDN*ICAO Code:*Callsign: Independent-Atlanta Skylarks:Independent Air originated with the Atlanta Skylarks Travel Club, and it operated flights for this club beginning in July 1966 with a single DC-7. By early 1970s it expanded charter operations to the Caribbean using a...

 Flight 1851
, a Boeing 707
Boeing 707
The Boeing 707 is a four-engine narrow-body commercial passenger jet airliner developed by Boeing in the early 1950s. Its name is most commonly pronounced as "Seven Oh Seven". The first airline to operate the 707 was Pan American World Airways, inaugurating the type's first commercial flight on...

-331B on an American charter flight from Bergamo
Bergamo
Bergamo is a town and comune in Lombardy, Italy, about 40 km northeast of Milan. The comune is home to over 120,000 inhabitants. It is served by the Orio al Serio Airport, which also serves the Province of Bergamo, and to a lesser extent the metropolitan area of Milan...

, Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

 to Punta Cana
Punta Cana
Punta Cana is part of the newly created Punta Cana-Bávaro-Veron-Macao municipal district in La Altagracia, the easternmost province of the Dominican Republic. The area is best known for its beaches and balnearios, which face both the Caribbean and Atlantic, and it has been a popular tourist...

, Dominican Republic
Dominican Republic
The Dominican Republic is a nation on the island of La Hispaniola, part of the Greater Antilles archipelago in the Caribbean region. The western third of the island is occupied by the nation of Haiti, making Hispaniola one of two Caribbean islands that are shared by two countries...

, struck Pico Alto on approach to Santa Maria Airport
Santa Maria Airport (Azores)
Santa Maria Airport is an airport on Santa Maria Island, in the autonomous region of the Azores, Portugal, serving the municipality of Vila do Porto, within the archipelago and to the continent...

 in the Azores
Azores
The Archipelago of the Azores is composed of nine volcanic islands situated in the middle of the North Atlantic Ocean, and is located about west from Lisbon and about east from the east coast of North America. The islands, and their economic exclusion zone, form the Autonomous Region of the...

 for a scheduled stopover. The aircraft was destroyed with the loss of all passengers and crew.

Accident

During final approach to Santa Maria Airport, the airport controller instructed that the aircraft should descend to 3,000 feet for a runway 19 ILS
Instrument Landing System
An instrument landing system is a ground-based instrument approach system that provides precision guidance to an aircraft approaching and landing on a runway, using a combination of radio signals and, in many cases, high-intensity lighting arrays to enable a safe landing during instrument...

 approach. In that transmission, a trainee controller had also transmitted an incorrect QNH
QNH
QNH is one of the many Q codes. It is defined as, "barometric pressure adjusted to sea level." It is a pressure setting used by pilots, air traffic control , and low frequency weather beacons to refer to the barometric setting which, when set on an aircraft's altimeter, will cause the altimeter to...

 (barometric altimeter) setting that was 9 hPa
Pascal (unit)
The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre...

 too high. The approach instructions were briefly unheard since the pilot had re-keyed his mike to acknowledge the new QNH, and likely did not hear the second repeat of the 3,000 ft safe altitude, declaring: "We’re re-cleared to 2,000 feet...". Although the first officer questioned the barometric altitude, the captain agreed that the first officer had heard the read-back correctly.

After being cleared to the ILS approach, the crew failed to accomplish an approach briefing, missing an opportunity to notice the 3,000 ft minimum safe altitude and the presence of Pico Alto.

Leveling off at 2,000 ft, the airliner experienced light turbulence at 250 knots and heavy turbulence at 223 knots at 700 ft near Santo Espírito
Santo Espírito
Santo Espírito is a Portuguese civil parish, located in the municipality of Vila do Porto, in the autonomous region of Azores. It has a population of 723 inhabitants and a total area of 26.65 km². The economy of the parish is based on agriculture...

.

The airliner was level as it impacted the ridge of Pico Alto, colliding with a rock wall on the side of a road at an altitude of 1795 ft. There was no evidence of an in-flight emergency and the altimeter was found correctly set to 1027 mb.

Report

The Board of Inquiry determined the accident was due to non-observance by the crew of established operating procedures which led to the deliberate descent of the aircraft to 2000 feet when the published minimum sector altitude was 3000 feet. It also found that the controller had put the aircraft 240 ft below that indicated on-board the aircraft, exacerbating the original error by the first officer.

Other factors:
  • Bad communications techniques on the part of the co-pilot and controller, including the non-adherence to standard phraseology in some of the ground communication.
  • Neglecting aerodrome control tower procedures in not requesting a readback of the descent clearance.
  • The limited international flying experience of the crew and the airline's deficient crew training that did not include emergency maneuvering techniques for terrain avoidance.
  • Non-compliance with AIP Portugal flight plan procedures and authorized routes.

External links

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