Incident Overview
On July 24, 2014, Air Algerie Flight AH5017, a McDonnell Douglas MD-83 operated by Swiftair, crashed en route from Ouagadougou, Burkina Faso to Algiers, Algeria, killing all 116 passengers and crew onboard. The crash occurred near Gossi, Mali, following the crew’s request to divert due to poor weather conditions. The investigation revealed that weather conditions, combined with an aerodynamic stall, led to the crash.
Flight Details
• Aircraft: McDonnell Douglas MD-83
• Registration: EC-LTV
• Operator: Swiftair on behalf of Air Algerie
• Flight Number: AH5017
• Origin: Ouagadougou, Burkina Faso
• Destination: Algiers, Algeria
• Occupants: 116 (110 passengers, 6 crew members)
• Fatalities: 116
Sequence of Events
Flight AH5017 departed Ouagadougou at 01:17 UTC, scheduled to reach Algiers after a 4-hour flight. The aircraft climbed to its cruising altitude of FL310 (31,000 feet) and maintained this altitude for approximately 40 minutes. At 01:40 UTC, the crew requested a course deviation due to a storm system ahead, typical of the intense weather patterns in the Sahel region during the monsoon season.
The flight continued to encounter severe weather, with reports of thunderstorms, turbulence, and wind shear in the vicinity. At 01:47 UTC, the aircraft began a left turn, consistent with an attempt to avoid the weather system. At this point, the aircraft encountered significant turbulence, resulting in a loss of altitude. Shortly after, the crew lost control of the aircraft, and it descended rapidly.
Radar data showed that the aircraft entered an uncontrolled descent, and communication with air traffic control was lost. The aircraft impacted the ground near Gossi, Mali, approximately 50 minutes after departure.
Weather Conditions
The region where Flight AH5017 was flying is known for its volatile weather patterns, particularly during the rainy season. Meteorological data indicated the presence of a large convective system with severe turbulence, vertical wind shear, and intense storm activity. The crew’s request to divert highlights the dangerous weather conditions they were attempting to navigate. However, despite the request, the aircraft still encountered significant turbulence and strong updrafts/downdrafts.
Flight Crew Actions
The cockpit voice recorder (CVR) and flight data recorder (FDR) indicated that the crew was actively managing the aircraft’s performance in response to weather conditions. However, the aircraft’s behavior suggests the flight crew may have encountered an aerodynamic stall as a result of vertical wind shear, leading to a loss of lift. The MD-83’s behavior in severe turbulence further contributed to the loss of control.
Despite the crew’s efforts, the aircraft likely entered a stall condition, and recovery procedures were not successful. Analysis of the FDR revealed that pitch, airspeed, and thrust settings became inconsistent with standard operating procedures, indicating that the aircraft was no longer responding to control inputs as expected.
Root Cause Analysis
The investigation determined that the primary cause of the accident was the aircraft’s encounter with severe weather conditions, including turbulence, wind shear, and updrafts/downdrafts, which overwhelmed the aircraft’s performance capabilities. The aerodynamic stall that ensued was a direct result of these conditions, leading to a loss of control.
Contributing factors included:
1. Inadequate Weather Avoidance: Although the crew attempted to deviate around the storm, the aircraft still entered a hazardous weather system, possibly due to insufficient real-time weather data or the speed at which the storm system was evolving.
2. Aircraft Performance in Severe Turbulence: The MD-83’s performance in severe weather conditions became compromised, particularly during the encounter with vertical wind shear.
3. Crew Training and Experience: While the crew attempted to recover the aircraft, their efforts were unsuccessful, suggesting potential issues with handling stall recovery procedures in such extreme weather conditions. This raised questions regarding the crew’s training and experience in managing severe weather-related emergencies.
Aircraft Systems
The McDonnell Douglas MD-83 is equipped with systems designed to enhance situational awareness and support weather avoidance, including weather radar. However, the effectiveness of these systems can be diminished in extreme conditions. Furthermore, weather radar systems are limited in their ability to detect vertical wind shear and turbulence, which can present significant risks during flight through convective storm systems.
Final Moments and Wreckage
The aircraft impacted the ground in a near-vertical descent, consistent with a stall-induced loss of control. The wreckage was scattered over a wide area, indicative of a high-speed impact. Investigators recovered the CVR and FDR, which provided critical data for the investigation.
Post-crash analysis of the wreckage showed no evidence of pre-impact structural failure or in-flight fire. The engines were operating normally at the time of the crash, further supporting the conclusion that the accident was the result of an aerodynamic stall induced by severe weather conditions.
Conclusion and Recommendations
The crash of Air Algerie Flight AH5017 was a tragic event caused primarily by the aircraft’s encounter with severe weather, which led to a loss of control due to aerodynamic stall. While the crew made efforts to avoid the storm system, the aircraft still entered an area of significant turbulence and vertical wind shear, which overwhelmed its performance capabilities.
Key Recommendations:
1. Improved Weather Monitoring and Reporting: Airlines and aviation authorities must ensure that flight crews have access to the most accurate, real-time weather information. This includes enhanced capabilities for detecting wind shear, turbulence, and storm systems during flight.
2. Crew Training for Severe Weather Conditions: Enhanced training programs focused on handling severe turbulence, wind shear, and stall recovery procedures should be implemented to ensure that flight crews are adequately prepared for such situations.
3. Weather Avoidance Procedures: Airlines should review their weather avoidance protocols to ensure that crews are provided with the necessary tools and guidelines to make informed decisions regarding storm deviations and route adjustments.
4. Aircraft Systems Upgrades: Enhancements in aircraft weather radar systems, including the ability to detect wind shear and turbulence, should be considered for improved safety when flying through regions prone to severe weather.
This accident serves as a reminder of the dangers posed by extreme weather conditions and the importance of preparedness, training, and technology in mitigating the risks associated with aviation operations in such environments.
