Austral Líneas Aéreas Flight 2553

Austral Líneas Aéreas Flight 2553, also known as Austral 2553, was an Argentinian domestic, scheduled Posadas–Buenos Aires service operated with a McDonnell Douglas DC-9-32 that crashed on the lands of Estancia Magallanes, Nuevo Berlín, 32 kilometres (20 mi; 17 nmi) away from Fray Bentos, Uruguay, on 10 October 1997.[1][2][3] All 74 passengers and crew died upon impact.[1][4][5] The accident remains the deadliest in Uruguayan history.[1]

Austral Líneas Aéreas Flight 2553
LV-WEG, the aircraft involved in the accident seen in 1995.
Accident
Date10 October 1997
SummaryInstrument malfunction, pilot error
SiteNuevo Berlín, Uruguay
33°01′18.5″S 57°49′20.7″W
Aircraft
Aircraft typeMcDonnell Douglas DC-9-32
OperatorAustral Líneas Aéreas
RegistrationLV-WEG
Flight originGeneral José de San Martín Airport, Posadas, Argentina
DestinationAeroparque Jorge Newbery, Buenos Aires, Argentina
Occupants74
Passengers69
Crew5
Fatalities74
Survivors0

Aircraft and crew

The aircraft involved in the accident was a McDonnell Douglas DC-9-32, registration LV-WEG.[1][2][6] It had its maiden flight in 1969,[1] and was 28 years old at the time of the accident. It had previously operated for Iberia with registration EC-BQT, and it was transferred to the airline in 1993 after the buyout of the company by the Spanish carrier.[7][8][9]

The captain was 40-year-old Jorge Cécere, who had been with the airline since 1989 and logged 9,238 hours, including 223 hours on the DC-9. The first officer was Horacio Núñez, who was also 40. He had been with the airline since 1993 and had 2,910 flight hours. He was more experienced on the DC-9 than captain Cécere, with 1,384 hours on that aircraft.[10]:8,11–13[11][12]

Accident

The aircraft, which left from Posadas and was due to land in Aeroparque Jorge Newbery, Buenos Aires,[6] was forced to divert towards Fray Bentos to avoid a storm. Examination of the aircraft's flight data recorder (FDR) revealed that shortly after the diversion occurred, the aircraft airspeed indicator began to fall to an alarmingly low indicated airspeed. Unbeknownst to the pilots, this was caused not directly, by a loss of power, but by ice formed inside the pitot tube, which reads the airspeed for the indicator by measuring the pressure of inflow air. The ice obstructing the pitot tube reduced the air inflow, thus giving an erroneously low indicated airspeed.

In response to what they interpreted as a loss of engine power, the pilots gradually increased power from the engines in order to maintain airspeed; seeing no improvement, they contacted the control tower in Ezeiza Airport and requested clearance to descend to a lower altitude. After receiving no response, the Captain decided to descend to a lower altitude to increase speed even with no clearance received from the Air Traffic Control. While descending from their assigned altitude of 35,000 feet and reaching 31,700 feet, the Captain identified the faulty airspeed indication and ordered the First Officer to stop descending and to reduce speed, because the readings were unreliable. However, the First Officer disregarded the Captain's commands and deployed the wings' slats to maintain their altitude and lower the plane's stall speed. Consequently, at this point the airplane was actually flying at a higher speed than normal; it was descending, which further increased airspeed to a point dangerously near to VNE, the "never exceed speed", above which structural damage to the aircraft might occur.

With the slats extended at a speed beyond their operational limits, one of them was torn from the aircraft, causing catastrophic asymmetry in the airflow over the wings. The aircraft immediately became uncontrollable and crashed.

According to an investigation by both the Argentine and Uruguayan Air Forces, the pitot tube—the primary instrument for measuring aircraft airspeeds—froze when the aircraft passed through a 15,000-metre (49,000 ft) high cumulonimbus cloud,[1] blocking the instrument and causing it to give a false reading. Compounding this problem was the absence of the alarm designed to report such a malfunction (raising serious questions about inspection irregularities by the Argentine Air Force).

During the descent, the FDR recorded an increase in the airspeed from 300 km/h (160 kn) to 800 km/h (430 kn) in three seconds, which could only signify the sudden unfreezing of the pitot tube. Specialists estimated that the aircraft crashed almost perpendicularly to the ground,[6] at a speed of 1,200 km/h (650 kn). Depending upon the source, the crater left by the crash was 6 metres (20 ft) deep and 30 m (98 ft) wide,[3] 25 feet (7.6 m) deep and 30 ft (9.1 m) wide,[13] or 25 ft (7.6 m) deep and 80 ft (24 m) wide.[1]

See also

References
  1. Accident description at the Aviation Safety Network. Retrieved on 26 May 2011.
  2. Solans, Roberto (12 October 1997). "Catástrofe aérea: hubo 73 muertos" [Air disaster: 73 dead]. La Nación (in Spanish). Archived from the original on 15 March 2014.
  3. "Imágenes del espanto en Nuevo Berlín" [Scary pictures at Nuevo Berlín]. La Nación (in Spanish). 12 October 1997. Archived from the original on 24 August 2016.
  4. "Timeline: Worst air accidents in Argentina". Buenos Aires Herald. 19 May 2011. Archived from the original on 15 March 2014.
  5. "El piloto no debió entrar en la tormenta" [The pilot should not have entered into the storm]. La Nación (in Spanish). 13 October 1997. Retrieved 4 May 2011.
  6. "Storm may be to blame for Austral DC-9 crash". Flight International: 11. 22–28 October 1997. Retrieved 29 April 2011.
  7. "LV-WEG Austral Líneas Aéreas McDonnell Douglas DC-9-32 – cn 47446 / 561". Retrieved 17 January 2017.
  8. "Aircraft Data LV-WEG, 1969 Douglas DC-9-32 C/N 47446". Retrieved 17 January 2017.
  9. "LV-WEG Austral Líneas Aéreas McDonnell Douglas DC-9-32, MSN 47446". OneSpotter.com. OneSpotter.com | Plane Spotting, Photography, Aircraft Database. Retrieved 10 June 2020.
  10. "INFORME FINAL DE ACCIDENTE DE AVIACION McDONNELL DOUGLAS DC-9-32 AUSTRAL, LINEAS AEREAS CIELOS DEL SUR S.A. LV-WEG NUEVO BERLIN - R.O.U. - 10 DE OCTUBRE DE 1997" [FINAL REPORT ON AVIATION ACCIDENT McDONNELL DOUGLAS DC-9-32 AUSTRAL, LINEAS AEREAS CIELOS DEL SUR S.A. LV-WEG NEW BERLIN - R.O.U. - OCTOBER 10, 1997] (PDF) (in Spanish). National Civil Aviation and Aviation Infrastructure Direction. Archived from the original (PDF) on 18 April 2012. Retrieved 10 June 2020.
  11. "El piloto no debió entrar en la tormenta" [The pilot should not have entered the storm]. lanacion.com.ar (in Spanish). 13 October 1997. Retrieved 10 June 2020.
  12. "Austral: Peritos advirtieron que uso correcto del piloto automático hubiese podido evitar el accidente" [Austral: Experts warned that correct use of the autopilot could have prevented the accident]. El Territorio Misiones (in Spanish). 19 June 2019. Retrieved 10 June 2020.
  13. "75 Die in Crash of Argentine Plane in Uruguay". The New York Times. 12 October 1997. Archived from the original on 9 September 2016.
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