Government

Despite the fact that rebels announced officially two days later they shot down the aircraft, the Sudanese Government confirmed that visibility was low at the time of the accident with clouds at low height and poor weather conditions. As a result, officials said the accident was the consequence of a controlled flight into terrain (CFIT) after the crew descended too low on final.

It was determined that the crew was not focused on the landing procedure during the approach, causing the aircraft to be well above the glide. In such conditions, the aircraft landed 1,200 metres past the runway threshold (the runway is 2,000 metres long). After touchdown, the crew activated the reverse thrust systems on both engines but the spoilers were not used. With a landing distance of about 800 metres, the aircraft could not be stopped in a safely manner and the crew failed to initiate a go-around procedure.

Controlled flight into terrain.

Loss of control during takeoff following the crew's decision to perform the operation outside of the procedures established in the flight manual. The overconfidence of the crew as well as the operation of both engines at low regime were considered as contributing factors.

The immediate cause of the accident was the descent below the minimum descent altitude at an excessive rate of descent in weather conditions which prevented visual contact with the ground, as well as a delayed execution of the go-around procedure. Those circumstances led to an impact on a terrain obstacle resulting in separation of a part of the left wing with aileron and consequently to the loss of aircraft control and eventual ground impact.
Circumstances Contributing to the Accident:
1) Failure to monitor altitude by means of a pressure altimeter during a non-precision approach;
2) failure by the crew to respond to the PULL UP warning generated by the TAWS;
3) attempt to execute the go-around maneuver under the control of ABSU (automatic go-around)
4) Approach Control confirming to the crew the correct position of the airplane in relation to the RWY threshold, glide slope, and course which might have affirmed the crew's belief that the approach was proceeding correctly although the airplane was actually outside the permissible deviation margin;
5) failure by LZC to inform the crew about descending below the glide slope and delayed issuance of the level-out command;
6) incorrect training of the Tu-154M flight crews in the 36 Regiment.
Conducive circumstances
1) incorrect coordination of the crew's work, which placed an excessive burden on the aircraft commander in the final phase of the flight;
2) insufficient flight preparation of the crew;
3) the crew‘s insufficient knowledge of the airplane's systems and their limitations;
4) inadequate cross-monitoring among the crew members and failure to respond to the mistakes committed;
5) crew composition inadequate for the task;
6) ineffective immediate supervision of the 36 Regiment's flight training process by the Air Force Command;
7) failure by the 36 Regiment to develop procedures governing the crew's actions in the event of:
a) failure to meet the established approach criteria;
b) using radio altimeter for establishing alarm altitude values for various types of approach;
c) distribution of duties in a multi-crew flight.
8) sporadic performance of flight support duties by LZC over the last 12 months, in particular under difficult WC, and lack of practical experience as LZC at the SMOLENSK NORTH airfield.

The Accident Investigation Board (AIB) President found by clear and convincing evidence that the cause of this mishap was the mishap aircraft running out of fuel due to the mishap aircraft commander’s and mishap copilot’s failure to properly fuel plan and then refuel the mishap aircraft at Nouakchott with a sufficient amount to reach their destination. Once airborne, despite indications of a fuel shortage, the mishap crew did not divert to a suitable alternate airport early enough in the sortie to avoid this mishap. The AIB President also found sufficient evidence to conclude the following factors substantially contributed to the mishap: insufficient mission and flight planning; faulty decision-making; complacency; task misprioritization; channelized attention; and the mishap crew pressing to meet mission demands.

Controlled flight into terrain.