The Mali aircraft accident investigating commission published the interim report of their investigation into the accident involving an MD-83 in Mali in August 2014.
The airplane was operated by Spanish airline Swiftair on behalf of Air Algérie and was programmed to operate scheduled flight AH5017 from Ouagadougou Airport (OUA), Burkina Faso to Algiers Airport (ALG), Algeria.
The filed flight plan called for a departure via Niamey (NY), then ROFER via route UM608.
At 01:13, the controller cleared the crew to perform the departure via EPEPO, towards FL 310, with a turn to the right after takeoff. The controller had prepared for a departure of this flight via GAO through the EPEPO point, through which the aeroplane had passed at the time of its arrival at Ouagadougou from Algiers. The crew read back GUPOV (25 NM west of Ouagadougou) instead of EPEPO. The controller corrected the error. The crew read back correctly.
At 01:15 the crew took off, then turned to the right and took a 023° heading. At an altitude of about 10,500 ft, autopilot 1 was engaged, the autothrottle having been active since takeoff.
Nine minutes after takeoff, the crew said that they were passing through FL145 and that they estimated EPEPO point at 01:38, and Algiers at 05:06.
At 01:28, the aeroplane was transferred to the Ouagadougou ACC and the crew said that they were turning to the left on heading 356° due to a manoeuvre to avoide bad weather in the area.
During the climb towards FL310, the crew made three heading alterations to the left (of 28°, of 4° then of 8°), then an alteration to the right of 36° to return to heading 019°, close to the initial heading.
At 01:37, the aeroplane levelled off at FL310 at Mach 0.740. The autopilot then maintained the aeroplane’s altitude and heading, while the speed was controlled by the autothrottle. At the same time, the aeroplane was transferred to the Niamey ACC.
In the two minutes following level-off, the aeroplane’s speed increased. For about 30 seconds, the autothrottle was in MACH ATL mode. This mode engaged because the engine thrust needed to achieve the Mach target is greater than the thrust corresponding to the EPR limit value.
The engines’ EPR stabilised around 1.92 and the Mach changed from 0.758 to 0.762. The autothrottle then returned to MACH mode and the aeroplane continued to accelerate up to Mach 0.775.
At 01:30, the aeroplane’s speed started to decrease. About one minute later the autothrottle changed back to MACH ATL while the Mach was 0.752. Following that, the altitude remained stable, pitch and EPR increased progressively, while the engines’ N1 remained stable and the speed continued to decrease.
Between 01:41 min 38 and 01:44 min 29, the Niamey ACC and flight AH5017 tried to get in contact, but did not manage to do so. Flight RAM543K offered to act as the intermediary. The crew of flight AH5017 said, at 01:44, that they were at FL310 on an avoidance manoeuvre. The Niamey ACC heard this radio exchange and then gave them the 3235 transponder code. He also asked them to call back passing GAO and to transmit estimates for MOKAT point.
No answer, nor any other messages from flight AH5017, reached the Niamey ACC.
At 01:44, EPR and N1 fluctuations on both engines appeared for about 45 seconds. Then, for about 25 seconds, the EPR decreased then increased again on two occasions from 1.6 to about 2.5. The N1s varied between 70% and 91%. Some roll oscillations between 4° to the left and to the right appeared. The autothrottle disengaged between for four seconds between the first and second EPR variations.
At 01:45:06, the calibrated airspeed was 203 kt, the Mach 0.561 and the aeroplane started to descend. Pitch increased until it reached 10°, then decreased slightly while the deflection of the elevators and the position of the trimmable horizontal stabiliser continued pitching up. The EPR and the engines’ RPM started to decrease towards values corresponding to idle. The roll oscillations continued and the speed continued to decrease.
At 01:45:35, the autopilot disengaged. The altitude decreased by about 1,150 ft in relation to the flight level, the calibrated airspeed was 162 kt, the Mach 0.439 and both engines were almost at idle. The aeroplane’s pitch began to decrease and the bank was increasing to the left.
The aeroplane’s pitch and bank were then subject to significant changes. They reached, respectively, 80° nose-down and 140° bank to the left. The aeroplane was pitched nose-down and banked to the left until it struck the ground. The heading decreased continuously and the flight control surfaces remained mainly deflected pitch-up and in the direction of a bank to the right. Around twenty seconds before the impact, the engine speed and EPR increased again and reached values close to maximum thrust.
- Interim Report (PDF)