Le 16 août 2005, le vol WCW 708 a décollé de l’aéroport international Tocumen (MPTO), Panama, ...

On 16 August 2005, flight WCW 708 took off from Tocumen (MPTO) international airport, Panama, at 05:59 UTC bound for «Le Lamentin Fort de France» (TFFF) international airport, Martinique, in instrument meteorological conditions. At half-distance, there was an area of stratocumulus type cloud formation with heavy precipitation. The aircraft was airworthy and had no mechanical defects. Once it had reached flight level 330, the aircraft’s speed began to decay until it reached stall speed. The aircraft then went into a stall and continued to lose altitude until it struck the ground, in a flat area defined with an altitude of 119 feet above sea level, near the village of Machiques, State of Zulia, Venezuela.

 

CONCLUSIONS (EXTRACTS)

  • The use of the anti-icing system caused a drop in the proportion of engine pressure ratio (EPR) that, given the performance conditions linked to the inappropriate configuration of the autothrust system in EPR Limit Cruise mode, affected the aircraft’s energy state, by causing a progressive loss of speed. Consequently, the aircraft was flying behind the power curve, which meant that the thrust required for the aircraft to maintain its speed was greater than that which it was producing.
  • The facts gathered show that the speed indications were not correctly monitored and, consequently, that the continuous loss of speed was not identified, at the time that the energy drop-off was occurring, leading the aircraft to flying behind the power curve with a high angle of attack.
  • The crew identified that a decrease in aircraft performance had been reached that required descending to flight level 310. While the aircraft was descending through flight level 317, the engines suffered a loss of thrust and at the same time the stick shaker activated one second before the stall warning. 
  • At the moment the stall warning activated, the horizontal stabilizer trim began to increase its pitch-up action in a progressive manner until it reached the pitch-up stop.
  • None of the appropriate and necessary actions were taken in order to recover the aircraft’s energy state, the crew’s attention being focused on the engine instrument displays, even when the co-pilot said that he had identified the stall.

 

CAUSAL FACTOR:

The aerodynamic and performance conditions meant that the aircraft reached the critical condition that led to the stall situation. Subsequently, the crew’s resource management (CRM) and decision-making throughout the crisis were inappropriate. This situation was generated by the following factors:

  1. Inadequate situational and environmental awareness, which meant that the crew were not fully aware of the situation in terms of aircraft performance and behaviour.
  2. The lack of effective communication between the members of the flight crew which, during the decision-making process, reduced the chances of choosing appropriate and well–adapted alternatives and of setting priorities that corresponded to the actions to be taken in a critical or emergency situation (high altitude stall situation).

 

It must be said that the cause of the accident is linked to the absence of appropriate actions to prevent the aircraft from going into a stall situation, and, when the emergency situation occurred, and until impact with the ground, inappropriate setting of priorities in carrying out procedures. Subsequently, actions were taken that were outside the limits and parameters established in the manufacturer’s performance manual, along with inappropriate flight planning with no consideration for the meteorological aspects, in addition to the crew’s incorrect and late interpretation of the drop in the aircraft’s energy state. Thus, in terms of classification, the available facts lead to the conclusion that «human factors» were the cause of this accident.

The JIAAC Commission issued ten safety recommendations in its final report: seven to the aviation authorities, one to the aircraft manufacturer Boeing and two to the manufacturers of Flight Data Recorders.

Flight Data Recorder - flight WCW 708
Cockpit Voice Recorder - flight WCW 708

Publications

Press release

  • The following information has been released by the Comite de Investigacion de Accidentes Aereos (CIAA) of Venezuela. All States assisting the investigation -- France, Colombia and the United States -- agree with the factual findings. The BEA is distributing this information at the request of the Venezuelan Investigator-in-Charge.
    Wreckage

    Movement of the wreckage has been delayed due to very heavy rains in the area where the airplane crashed. However, it should be moved to a secure area in Maracaibo in the next few days. Once the wreckage has been moved, additional inspections will be completed. Initial examinations on site revealed:

    Ground scars indicate that the airplane impacted in a nose up and slight right roll attitude.

    Wreckage was distributed over a triangle shaped area that was approximately 205 meters long and 110 meters at its widest point.

    Both engines exhibited indications of high-speed compressor rotation at the time of ground impact.

    The engine inlets, empennage and wing leading edges showed no sign of pre-impact damage.

    The horizontal stabilizer was found in more or less the full airplane nose up position (about 12 units nose up).

    Flight recorders

    The cockpit voice recorder (CVR) and flight data recorder (FDR) were downloaded at the Bureau d'Enquetes et d'Analyses pour la Securite de l'Aviation Civile (BEA) laboratory near Paris, France, during the week of September 5, 2005.
    Both the FDR and CVR casings were severely damaged due to impact forces. Both recorders operated until impact.
    Flight Data Recorder (FDR)

    The FDR protected module was in good condition and the magnetic tape was extracted in good condition. The investigation has gained good information from the recorder.

    However, several parameters were not recorded as designed, including left engine pressure ratio (EPR), pitch attitude, roll attitude, magnetic heading, and column position.
    The following events are recorded on the FDR:

    • The accident flight lasted about one hour from takeoff to the end of the recording.
    • The flight reached its initial cruise altitude of flight level (FL) 310 at about 6:25 UTC (universal coordinated time).
    • At about 6:41 UTC, about 20 minutes before the end of the recording, the airplane began a normal climb to FL330. It levelled off at about 6:43 and accelerated to Mach 0.76. The right engine EPR was consistent with normal climb and cruise values.
    • About 90 seconds after reaching Mach 0.76 (6:49 UTC), the airspeed began to steadily decrease. The horizontal stabilizer moved from about 2 units nose up to about 4 units nose up during this deceleration.
    • About 3 minutes and 30 seconds (6:57 UTC) from the end of recording, the Mach number reached about 0.60. The autopilot was then disengaged and the airplane started to descend from FL330.
    • As the airplane descended past about FL315, the airspeed continued to decrease and the right engine EPR decreased to about flight idle.
    • The airplane descent rate increased after passing through FL310.
    • The airspeed reached a minimum of about 150 indicated air speed (IAS) knots at about FL250.
    • Right engine EPR stayed at approximately flight idle through the descent and even increased several times, including shortly before the end of the recording.
    • Once the airplane started to descend, the horizontal stabilizer moved in increments to about 12 units nose up (which is about full nose up trim) while descending through FL200.

    Cockpit Voice Recorder (CVR)

    The CVR protected module was partly opened due to impact forces. Overall, the magnetic tape was in good condition, but the tape was partially cut due to impact forces. The overall quality of the recoding is poor, with many areas of static and loud background noises. However, valuable data was obtained.
    Almost all crew discussions to communicate with each other and with air traffic control (ATC), in Colombia and Venezuela, were in Spanish.
    The CVR recorded the last 32 minutes of the accident flight.
    The following events are recorded on the CVR:

    • At about 06:53 UTC, approximately 8 minutes before the end of recording (while the airplane is level at FL330) the flight crew discusses weather concerns that included possible icing conditions. The flight crew also discusses turning on engine and airfoil anti-ice.
    • About 3 minutes and 30 seconds (6:57 UTC) before the end of the recording, the crew requests and is cleared to descend to FL310.
    • About 3 minutes before the end of the recording, an audio warning similar to altitude alert is heard, followed 22 seconds later by a sound similar to stick shaker (6:58 UTC) and then an aural stall warning alert. These warnings sound continuously until the end of the recording.
    • The flight crew requests subsequently lower altitudes of FL290, FL240, and finally 14,000 feet.
    • The flight crew does not declare an emergency, and they do not refer to any checklist during the descent.
    • About 1 minute after the start of the sound similar to the stick shaker, the flight crew states that they had a dual engine flameout when asked by ATC if they had a problem.
    • Last radio transmission from the flight crew to ATC was at about 07:00:11 UTC.
    • About 8 seconds before the end of recording, a ground proximity warning system (GPWS) warning starts to be heard and continues to the end of recording.
    • The time from first sound similar to stick shaker, to the end of the recording is about 2 minutes and 46 seconds.
    • The end of the tape occurs at about 7:00:31 UTC.
  • Work has been completed at the BEA on reading out the flight recorders from the West Caribbean Airways MD 82 involved in the accident near Maracaibo (Venezuela) on 16 August 2005. Copies of the Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR) recordings have been given to the representatives of the four States involved in the technical investigation.

    The data recovered has not made it possible, at this stage of the investigation, to determine the exact circumstances of the accident, due to the quality of some of the recorded data fields. Additional work will be required, within the context of the technical investigation led by Venezuela.

    It should be noted that investigations into this accident are also being undertaken by the French and Venezuelan judicial authorities. These authorities followed the work carried out at the BEA and copies of the recordings have been given to them.

  • It has been possible to extract the data corresponding to flight WCW 708 of 16 August 2005 from the Cockpit Voice Recorder (CVR) and the Flight Data Recorder (FDR). Working copies have been given to the Venezuelan Judicial Authorities, to the French Judicial Authorities and to the representatives of the investigative bodies of the four countries involved.

    The technical investigators have now started the validation phase, that is to say they are carrying out the additional work required to analyze the recorded data.

  • The flight recorders from the MD 82 arrived in France this morning. Readout of the recorders began at the BEA in the presence of safety investigators from Venezuela, Columbia and the United States, as well as representatives of the judicial authorities of France and Venezuela.

    The work may take several days. Additional information will be released if necessary.

  • The BEA's investigators have recently gained access to the flight recorders and were able to observe that, although they were damaged in the accident, the Crash Survivable Memory Unit (CSMU) of each recorder appeared to be in good condition. There is thus a reasonable expectation that it will be possible to read out the data, if it is recorded.

    The documentation relating to these recorders has been requested from the airline.

  • Late yesterday evening, the BEA was informed by the Venezuelan authorities responsible for the technical investigation that the flight recorders from the Colombian airplane will be sent to France in the near future. The investigators from both countries, along with the judicial authorities, are now engaged in preparing the conditions for this transfer.

    The work will of course begin with tests to ascertain whether the recorders functioned normally and to ensure that the data was not destroyed by the accident. The data will then be read out, decoded and presented in a format that will be useable for the investigation.

  • Following the accident that occurred in Venezuela on 16 August 2005 to the West Caribbean Airways Boeing Mc Donnell Douglas MD82, registered HK-4374X, flight WCW 708, that was flying from Panama City to Fort-de France, Martinique,  the BEA is sending a team to the site.

    You are reminded that, in accordance with the provisions of Annex 13 to the Convention on International Civil Aviation, known as the Chicago Convention, the safety investigation into this accident will be conducted by Venezuela. In accordance with international rules, communication of technical information about this accident and the progress of the investigation is the responsibility of the Venezuelan authorities.