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Last updated: 21 October 2018
Status:Final
Date:Wednesday 6 June 2012
Time:20:00
Type:Silhouette image of generic SW4 model; specific model in this crash may look slightly different
Swearingen SA227-AC Metro III
Operator:Air Class Líneas Aéreas
Registration: CX-LAS
C/n / msn: AC-482
First flight: 1982
Total airframe hrs:26158
Engines: 2 Garrett TPE331-11U-611G
Crew:Fatalities: 2 / Occupants: 2
Passengers:Fatalities: 0 / Occupants: 0
Total:Fatalities: 2 / Occupants: 2
Aircraft damage: Destroyed
Aircraft fate: Written off (damaged beyond repair)
Location:1,5 km (0.9 mls) S off Isla de Flores, Rio de la Plata (   Uruguay)
Phase: En route (ENR)
Nature:Cargo
Departure airport:Montevideo-Carrasco Airport (MVD/SUMU), Uruguay
Destination airport:Buenos Aires/Ezeiza-Ministro Pistarini Airport, BA (EZE/SAEZ), Argentina
Narrative:
A Swearingen SA227AC Metro III cargo impacted the waters of the Rio de la Plata during a flight from Montevideo-Carrasco Airport (MVD) to Buenos Aires/Ezeiza, Argentina. The wreckage was located on July 20, 2012 in 8 feet deep water south off Isla de Flores. Both pilots were killed.
The flight took off about 19:55 from runway 06 at Montevideo. While climbing to the assigned altitude of FL80 the airplane entered a left hand turn. The controller contacted the flight. The crew replied they would change course to the SARGO waypoint. This was the last contact with the flight.

Probable Cause:

Probable Cause
Loss of Control of the Aircraft due to being flying with erroneous indications of the flight instruments, added to the possible formation of crystalline ice on its structure, causing a loss of situational awareness of the crew.

Contributing factors
- Lack of Aeronautical Weather information for the area at the time of Operation.
- Lack of confidence in the Meteorological Radar of the Aircraft (the PF had made several notes in the RTV about its operability).
- According to the different analyses, it could be determined that the 115 Volts A.C. electrical system was not energized, so it is presumed that the checklist was not performed correctly in different procedures, which led to the avoidance of control items for the operation of navigation instruments. (The ignition control of the inverters is marked with an asterisk in the aircraft checklists, which determines that the item must be performed with the assistance of the NFP) .
- The PF had made its last five flights in another aircraft (CX-CLS), in which although it is the same model as the accident, the inverters do not energize the Navigation Instruments.
- The Flight Plan presented showed the CX-CLS aircraft as planned to perform the Mission.
- TWR request for take-off before the time determined by the flight plan.
- The taxiing was too fast, which conditioned the correct checking of the checklists for takeoff.
- Not recognizing the failure of Instruments, motivated to make a turn that diverted the Aircraft from the route and directed it towards a Cloud System with Freezing conditions.
- Not realizing the possible formation of crystalline ice in the structure of the aircraft, making a turn that aggravated the situation.
- Possible overconfidence of the PF accompanied by the short experience of the PNF and the lack of an interactive CRM.
- Possible blockage of the static pitot system, which would generate erroneous indications of speed, height and attitude.
- Possible loss of situational awareness (perception of self and aircraft in relation to dynamic flight environment and threats, with ability to predict what will happen based on perception)
- By not energizing the Flight System, the Artificial Horizon Instrument (ADI) model installed in the Aircraft gives a permanent ascent indication. This model of instrument does not have an indication flag when it is out of operation, the inoperability of the instrument is indicated at the bottom of the instrument where there is a bar that only changes color from red (out of operation) to black (operational).
- Maintaining a flight with speeds above the VMO, a situation aggravated by a turn; being in weather conditions where speed must be reduced to maintain control of the aircraft.
- Location of a GPS not enabled in a position that could confuse the crew for its luminosity.

Accident investigation:
cover
Investigating agency: CIAIA
Status: Investigation completed
Duration: 3 years and 5 months
Accident number: No. 541
Download report: Final report

Classification:

Loss of control

Sources:
» El Observardor
» ifronline.blogspot.com.br


Photos

photo of Swearingen SA227AC Metro III CX-LAS
Engine Garrett TPE331-11U-611G arriving after being recovered from Rio de la Plata onboard Uruguayan Navy ROU Maldonado.
photo of Swearingen SA227AC Metro III CX-LAS
photo of Swearingen SA227AC Metro III CX-LAS
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Map
This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path.
Distance from Montevideo-Carrasco Airport to Buenos Aires/Ezeiza-Ministro Pistarini Airport, BA as the crow flies is 228 km (142 miles).
Accident location: Global; accuracy within tens or hundreds of kilometers.

This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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