8th of November 2017, Dual Engine Failure, Blog #759.
On 8 November 2017, an Airlink Avro RJ85 operating flight 8103 departed Harare, Zimbabwe, on a scheduled service to Johannesburg, South Africa. On board were 34 passengers and four crew members. Weather conditions were good, and the aircraft climbed normally to its cruise altitude of FL340.
At approximately 17:38 UTC, while cruising in South African airspace near the UTULI reporting point, the flight crew heard a loud bang and noticed the aircraft yawing to the right. Engine indications immediately showed that both engines on the left wing had become inoperative.
The investigation later determined that the event began with a catastrophic failure of Engine No. 2. During the failure, turbine fragments were released from the engine and struck the Full Authority Digital Engine Control (FADEC) unit of the adjacent Engine No. 1. The damage caused Engine No. 1 to fail as well, leaving the aircraft operating on the two engines mounted on the right wing.
The flight crew declared a MAYDAY and carried out the appropriate emergency procedures. Search and rescue services were alerted, and nearby diversion options were reviewed. Air Force Base Makhado was placed on standby should an immediate diversion become necessary.
While the cabin crew informed passengers and prepared the cabin, the pilots assessed the aircraft's handling characteristics and overall condition. They also coordinated with Airlink's Maintenance Control Centre to discuss the situation and evaluate available options.
At the time of the failure, the aircraft was approximately 240 nautical miles from OR Tambo International Airport. After considering aircraft performance, weather conditions, available airfields, and the overall situation, the crew determined that continuing to Johannesburg was the most appropriate course of action.
Air traffic control provided priority handling and assigned Runway 21R for the arrival. During the approach, the cabin crew completed preparations for a precautionary emergency landing, while emergency services positioned themselves in anticipation of the aircraft's arrival.
Despite having lost both engines on one wing, the Avro RJ85 remained fully controllable throughout the descent and approach. At 18:39 UTC, approximately one hour after the initial failure, the aircraft landed safely on Runway 21R at OR Tambo International Airport. No injuries were reported among the passengers or crew. The aircraft sustained damage to both no. 1 and 2 engines on the port side wing of the aircraft. In addition, the turbine blades of no. 2 engine struck the no. 1 engine cowlings.
The engine failure was investigated by the South African Civil Aviation Authority Accident and Incident Investigation Division.
The cause of the no2 engine uncontained failure was attributed to the LP turbine retaining nut becoming dislodged resulting on the fourth-stage turbine rotor disk disengaged from the LP turbine shaft. The fourth-stage turbine rotor disc compromised the turbine casing and turbine debris from the no. 2 engine struck the no. 1 engine, causing an un-commanded shutdown and leading to a catastrophic failure of both port-side engines.
Incorrect application of torque settings; or improper installation due to a possible mis-stacking of the over-speed ring during maintenance on the engine was identified as contributory factor. The full Aircraft Incident Report, as published by the South African Civil Aviation Authority Accident and Incident Investigation Division, can be viewed by clicking on the .pdf file below;
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