Investigation Summary
The MD-83 was cruising at FL310 in an area of convective activity. Although the crew performed weather avoidance maneuvers, they did not activate the engine anti-ice systems. This allowed ice crystals to accumulate in the Pt2 pressure sensors located on the engine nose cones. These sensors provide the Engine Pressure Ratio (EPR) data used by the autothrottle to manage thrust. The icing caused the sensors to report erroneously high EPR values, leading the autothrottle to throttle back the engines to near-idle to avoid a perceived overboost. As thrust dropped, the aircraft began to lose airspeed. The autopilot, programmed to maintain the selected altitude, gradually increased the pitch to compensate for the loss of lift. The crew, likely distracted by weather and communication difficulties with Niamey ATC, failed to notice the decaying airspeed until the aircraft reached a critical angle of attack. The stickshaker and stall warnings triggered, but the crew did not initiate a stall recovery. Instead, the autopilot disengaged, and the aircraft rolled into a steep, nose-down spiral. The investigation was hampered by a malfunctioning Cockpit Voice Recorder (CVR), which had a tape that failed to erase old data, resulting in an unusable mix of multiple flights.
Final Conclusions
The final report by the Mali Commission of Inquiry (supported by the French BEA) concluded the accident resulted from the non-activation of engine anti-icing systems, leading to sensor obstruction and erroneous EPR values. This caused the autothrottle to limit thrust below what was required for level flight. The crew reacted too late to the speed decrease and failed to respond to the stall warning and stickshaker with appropriate recovery inputs. Contributing factors included inadequate FCOM procedures for Pt2 icing, insufficient pilot training for high-altitude stall recovery, and autopilot logic that continued pitch-up commands beyond the stall angle.
Photographic Evidence (1)
Video Analysis
The Crash of Air Algérie Flight 5017: MD-83 Stall Analysis — This video examines how iced EPR sensors led to a fatal stall and high-speed descent of an MD-83 over Mali in 2014. It details the crew's failure to activate anti-ice systems and the resulting loss of control.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Crew Experience
Captain
Agustín Comerón Mogio, age 47. Had 8,689 hours of experience as a captain. Since June 20, 2014, he had carried out 45 flights and 100 flying hours.
First Officer
Isabel Gost Caimari, age 42. Since June 20, 2014, she had carried out 43 flights and 93 flying hours.
Systems & Failure Modes
EPR (Engine Pressure Ratio) Sensors
Pressure sensors located on the engine nose cones that measure the ratio of inlet to exhaust pressure to determine thrust. Icing of these sensors led to false high readings.
Autothrottle
The system used the erroneous EPR data to incorrectly conclude the engines were producing too much power, leading it to reduce thrust to near-idle during cruise.
Autopilot
In altitude-hold mode, the autopilot increased the pitch to maintain 31,000 feet as speed bled off, eventually stalling the aircraft.
Interesting Facts
- 01All 116 people on board, including 6 Spanish crew members, were killed.
- 02The number of French nationals on board is reported as 52 by Air Algérie, though other sources cite 54; the discrepancy is attributed to a high number of passengers with dual citizenship.
- 03The Cockpit Voice Recorder (CVR) was unusable due to a mechanical malfunction that caused new audio to be recorded over old audio without erasing it.
- 04The crew were seasonal employees of Swiftair; however, they had been active for approximately one month prior to the accident, with the Captain flying 100 hours and the First Officer 93 hours since June 20, 2014.
- 05The flight planning and dispatch process failed to account for ETOPS regulations, as the direct route was more than 320 nautical miles from a usable airport.
- 06Two similar previous incidents involving MD-80 series aircraft and Pt2 sensor icing were identified, including Spirit Airlines Flight 970 in 2002.
Safety Actions & Advisories
Crew Training Revision
Investigators recommended that operators ensure seasonal crews receive adequate refresher training and specific instruction on high-altitude stall recovery.
Anti-Ice Procedure Update
Recommendations were made to modify FCOM procedures to mandate anti-ice activation in conditions conducive to Pt2 sensor icing, even if visible moisture is not present.
Known Controversies & Unanswered Questions
Swiftair Manslaughter Trial
Reference ↗A trial opened in Paris in March 2026 against Swiftair for involuntary manslaughter, with families alleging the airline failed to provide adequate training for its seasonal pilots.