Austral Líneas Aéreas Flight 2553

Accident summary
Date	10 October 1997
Type	Instrument malfunction, possible Pilot error
Site	Fray Bentos, Uruguay
Passengers	69
Crew	5
Injuries	0
Fatalities	74 (all)
Survivors	0
Aircraft type	McDonnell Douglas DC-9-32
Operator	Austral Líneas Aéreas
Tail number	LV-WEG
Flight origin	General José de San Martín Airport, Posadas, Argentina
Destination	Aeroparque Jorge Newbery, Buenos Aires, Argentina

Austral Líneas Aéreas 2553, better known as Austral 2553 is a Douglas DC-9 aircraft of Austral Líneas Aéreas, registered as LV-WEG ^[1] which crashed in Fray Bentos, Uruguay, on 10 October 1997. All 74 passengers and crew were killed on impact.^[2]

[edit] Accident

The aircraft, which left from Posadas and was headed to Buenos Aires, was forced to divert towards Fray Bentos to avoid a storm. Examination of the aircraft's black box revealed that shortly after this diversion, the aircraft's airspeed began to fall to an alarmingly slow velocity. In response, the pilots repeatedly increased power to the turbines in order to maintain velocity. Seeing no improvement in the aircraft's airspeed, the pilots then contacted the control tower in Ezeiza Airport and requested clearance to descend to a lower altitude. After receiving no response, the pilots lowered the aircraft's wing slats to maintain their altitude and lower the plane's stall speed. When lowering the slats however, one of them was torn from the aircraft, causing catastrophic asymmetry in the air flow over the wings. The plane immediately became uncontrollable and crashed.

According to an investigation by Argentine and Uruguayan Air Forces, the pitot tube—the primary instrument for measuring the aircraft's airspeed—froze when the aircraft passed through a cloud, blocking the instrument and causing it to give a false reading. Compounding this problem was the failure of the alarm designed to report such a malfunction (raising serious questions about inspection irregularities by the Argentine Air Force). Thinking that the aircraft was flying at dangerously low speeds, the pilots increased power to the engines. Far from flying at the low speed reported by the instruments however, the aircraft was actually exceeding its safe cruising speed, and far above a safe speed for deploying slats. During the deployment of the slats, one was torn off by the force of the high speed airflow traveling over the wing, which caused the plane to become unflyable and enter a steep descent.

During the descent, the black box recorded an increase in the plane's speed from 300 to 800 km/h in three seconds, which could only signify the sudden unfreezing of the pitot tube. Specialists estimated that the plane crashed perpendicularly to the ground at a speed of 1200 km/h, leaving a crater 70 meters wide and 10 deep.^[3]

The film Fuerza Aérea Sociedad Anónima by former pilot Enrique Piñeyro briefly explains the crash's major causes.

[edit] See also

• LAPA flight 3142

[edit] References

v • d • e ← 1996 Aviation accidents and incidents in 1997 1998→ Comair Flight 3272 (January 9) — Israeli helicopter disaster (February 4) — China Southern Airlines Flight 3456 (May 8) — Continental Airlines Flight 1760 (May 11) — Air Malta Flight 830 (June 9) — FedEx Flight 14 (July 31) — Korean Air Flight 801 (August 6) — Vietnam Airlines Flight 815 (September 3) — Garuda Indonesia Flight 152 (September 26) — Austral Líneas Aéreas Flight 2553 (October 10) — SilkAir Flight 185 (December 19) — Transavia Airlines Flight 462 (December 24) — United Airlines Flight 826 (December 28) Bold blue indicates incidents resulting at least 50 deaths (current article is always in bold black) Red indicates the deadliest incident in 1997