160 fatalities

2005-08-16: McDonnell Douglas MD-82 (HK-4374X) — West Caribbean Airways — Machiques, Venezuela

Machiques, VenezuelaFlight

On August 16, 2005, a McDonnell Douglas MD-82 (registration HK-4374X) operated by West Caribbean Airways was involved in an aviation accident near Machiques, Venezuela in flight. 160 people were killed. Investigators recorded the probable cause as: Given the aerodynamic and performance conditions, the aircraft was taken to a critical state, which led to a loss of lift. Consequently, the cockpit resource management (CRM) and decision-making during the development of emergency were misguided. This summary draws on records from the Bureau of Aircraft Accidents Archives (B3A).

Sourcesthe Bureau of Aircraft Accidents Archives (B3A)Primary reportUpdated 1781199393Data APIEditorial standards

Flight WCW 708, an MD-82, crashed in a swampy area after losing control during an emergency descent from FL330. All 160 occupants were killed as the aircraft disintegrated on impact.

Flight History

The MD-82 arrived at Panama City-Tocumen after a flight from Medellín-José María Córdova Airport (MDE). The aircraft was then prepared for a flight to the Caribbean island of Martinique. Flight WCW 708 departed Panama City at about 06:00 UTC and climbed to its cruising altitude of FL310. This altitude was reached at about 06:25 UTC. Sixteen minutes later, the airplane began a normal climb to FL330.

Inflight Events

At 06:49, the speed began to steadily decrease from Mach 0.76. The horizontal stabilizer moved from about 2 units nose up to about 4 units nose up during this deceleration. At 06:51 UTC, the crew reported at FL330 over the SIDOS waypoint, over the Colombian/Venezuelan border, and requested a direct course to the ONGAL waypoint. The controller instructed the crew to continue on the present heading and await further clearance direct to ONGAL. The flight crew meanwhile discussed weather concerns that included possible icing conditions and the possible need to turn on engine and airfoil anti-ice.

Emergency Descent

At 06:57 UTC, the flight crew requested permission to descend to FL310, which was approved. The autopilot was disconnected and the airplane began to descend. As the airplane descended past about FL315, the airspeed continued to decrease and the engine EPR decreased to about flight idle. Two minutes later, a further descent to FL290 was requested, but the controller at Maiquetía did not understand that this was a request from flight 708 and asked who was calling. Flight 708 responded and immediately requested descent to FL240. The controller inquired about the state of the aircraft, to which they responded that both engines had flamed out. The controller then cleared the flight to descend at pilot's discretion.

Loss of Control

In the meantime, the altitude alert warning had activated, followed by the stick shaker and the aural stall warning alert. The airspeed had reached a minimum of about 150 indicated air speed (IAS) knots at about FL250. The crew reported descending through FL140 and reported that they were not able to control the airplane. The aircraft descended at 7,000 ft/min, and finally crashed in a swampy area. The aircraft disintegrated on impact and all 160 occupants were killed. Debris were found on an area of 205 metres long and 110 metres wide. The entire descent from FL330 had taken approximately 3 minutes and 30 seconds.

Investigation Findings

The official investigation determined that given the aerodynamic and performance conditions, the aircraft was taken to a critical state, which led to a loss of lift. Consequently, the cockpit resource management (CRM) and decision-making during the development of emergency were misguided. This was caused by insufficient or improper awareness of environment (or situational awareness) that allowed the cockpit crew, not being full and timely aware of what was happening regarding the performance and behavior of the aircraft, and lack of effective communication between the cockpit crew that limited, within the decision making process, the possibility to timely choose appropriate alternatives and options and to set respective priorities in the actions taken at the time when it was established that there was a critical or emergency situation (stall condition at high altitude). The cause of the accident is determined by the absence of appropriate action to correct the stall of the aircraft, and also in the emergency up to the impact with the ground, at an inappropriate hierarchy of priorities in implementing the procedures. Subsequently, the operations were conducted outside of the limits and parameters set by the manufacturer's manual performance, together with an inadequate flight planning by failing to consider meteorological aspects, in addition a misinterpretation and late recognition of the energy state of the aircraft by the flight crew. Therefore, the evidence shows the classification of "Human Factor" as a cause of this accident.

Probable cause

Given the aerodynamic and performance conditions, the aircraft was taken to a critical state, which led to a loss of lift. Consequently, the cockpit resource management (CRM) and decision-making during the development of emergency were misguided. This was caused by the following: a) Awareness of environment (or situational awareness) insufficient or improper that allowed the cockpit crew, not being full and timely aware of what was happening regarding the performance and behavior of the aircraft. b) Lack of effective communication between the cockpit crew that limited, within the decision making process, the possibility to timely choose appropriate alternatives and options and to set respective priorities in the actions taken at the time when it was established that there was a critical or emergency situation (stall condition at high altitude). It is found that the cause of the accident is determined by the absence of appropriate action to correct the stall of the aircraft, and also in the emergency up to the impact with the ground, at an inappropriate hierarchy of priorities in implementing the procedures. Subsequently, the operations were conducted outside of the limits and parameters set by the manufacturer's manual performance, together with an inadequate flight planning by failing to consider meteorological aspects, in addition a misinterpretation and late of the energy state of the aircraft by the flight crew. Therefore, the evidence shows the classification of "Human Factor" as a cause of this accident.