Heavy Rains Have Delayed Removal Of Wreckage

The National Transportation Safety Board has issued its Factual Report on the August 16, 2005 downing of a West Caribbean Airways MD-82 that claimed the lives of all 160 people onboard. The findings, according to the NTSB, concur with those of French investigators, as well as the Comite de Investigation de Accicente Aereos (CIAA) of Venezuela.

According to evidence found at the scene near Machiques, Venezuela, the MD-82 (file photos of type, below) impacted in a nose-up attitude, with a slight rolling attitude to the right. Both engines exhibited indications of high-speed compressor rotation at the time of ground impact -- although the flight crew had reported a dual flameout, according to the cockpit voice recorder (CVR) -- and the engine inlets, empennage and wing leading edges showed no sign of pre-impact damage.

Movement of the wreckage has been delayed due to very heavy rains in the area where the airplane went down. However, the NTSB noted the wreckage should be moved to a secure area in Maracaibo in the next few days.

Investigators were able to locate both the cockpit voice recorder and flight data recorders (FDR), although both were damaged in the accident. The FDR was in good overall condition, however, and gave the following information to investigators --

• 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 leveled off at about 6:43 and accelerated to Mach 0.76. The right engine engine pressure ratio (EPR) was consistent with normal climb and cruise values. (The left engine EPR readings were judged inaccurate by the NTSB).
• 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, and 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.

According to NTSB investigators, the CVR protected module was partly opened due to impact forces. Overall, though, the magnetic tape was in good condition, although the tape was partially cut due to impact forces.

The overall quality of the recording 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 --

• 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. The 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.

The NTSB did not give a timeframe for when that agency, or the CIAA, expects to issue a probable cause report on the mishap.

FMI: www.ntsb.gov