Narrative:An ATR-42-300 operating Santa Bárbara Airlines Flight 518 was destroyed when it impacted the side of a mountain shortly after takeoff from Mérida-A Carnevalli Airport in Venezuela. All 46 on board were killed.
Mérida Airport is located in a mountain valley at an elevation of 5010 feet. Terrain in the valley rises from 1000 to 19.500 feet. Arrivals and departures have to use the Rio Chama corridor to the west of the airport. Runway 07 is used for landings and takeoffs have to be performed in the opposite direction, from runway 25.
Santa Bárbara Airlines however used an unpublished approach and departure procedure which let the aircraft use a valley to the northeast of the airport. This procedure saved about 15 minutes of flying time on the route to Caracas.
After all passengers had boarded for flight 518 to Caracas, it took about 30 minutes for the pilots to arrive at the aircraft. Being late, they immediately started the engines while simultaneously asking for permission to do so.
Because an Avior Airlines flight was approaching the airport, the crew were told to expedite their departure or wait for the arrival of the Avior aircraft. The flight crew decided to go and began taxiing 2 minutes and 40 seconds after startup. Consequently the AHRS (attitude and heading reference) system of the airplane was unusable. The aircraft needed to remain still for 3 minutes after the battery is turned on so that all gyroscopes, accelerometers and magnetometers can be stabilized and synchronized.
The AHRS provides attitude information for aircraft, including roll, pitch and yaw. The captain possibly expected to re-initialize the system while they were at cruising altitude.
After departure from runway 25 the crew planned to use the unpublished procedure. Climbing through clouds a 180-degree turn was initiated. Using the unreliable magnetic compass, the flight made a 270 degree turn, heading towards rising terrain. The captain took over control from the copilot. Visual contact with terrain was regained the crew noted they were heading for mountains. The captain tried to avoid rising terrain but the aircraft impacted the side of a mountain at 4100 m (13.400 feet).
Controlled Flight Into Terrain (CFIT) - Mountain
» LAGAD Aviation
» Instituto Nacional de Aeronáutica Civil (INAC)
METAR Weather report:
21:00 UTC / 17:00 local time: SVMD 212100Z 29008KT 9999 SCT013 BKN100 XX/XX Q1018=
22:00 UTC / 18:00 local time: SVMD 212200Z 25005KT 9999 BKN013 OVC100 20/12 Q1021=
3D terrain view and point of impact near Mérida Airport
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 Mérida-A Carnevalli Airport to Caracas-Simón Bolívar International Airport as the crow flies is 507 km (317 miles).
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.