EASA Issues SIB on Load Reduction Device Activation on LEAP Engines

The European Union Aviation Safety Agency (EASA) published a Safety Information Bulletin (SIB) to help manage potential risks that might follow the activation of an engine Load Reduction Device (LRD) on aircraft powered by CFM LEAP engines. The SIB was published in response to two incidents on Boeing 737-8 airplanes being powered by CFM LEAP-1B engines where a bird strike led to engine severe damage followed by subsequent activation of the engine LRD that led to a smoke event ensued. No injuries occurred during either incident and there have been no in-service events involving LRD activation in the Airbus A320 NEO family. 

An SIB can be addressed to the airline industry, in this case primarily airlines and other aircraft operators, and highlights a specific new or evolving safety issue. This SIB calls on operators of aeroplanes powered by CFM International LEAP engines to alert crews flying the relevant aircraft, so they are aware of risk management issue after engine LRD activation and prepare them to know how to respond in the case of such an event.

The LRD is a mechanical device that fuses to reduce the loads transmitted to the engine structure and the aeroplane during high fan unbalance events, such as a birdstrike. The LRD is designed to activate at a given load; it is not a system that is controlled by the flight crew.When the LRD is triggered (based on specific load thresholds), an oil leakage path is created, which allows leakage of both oil from the sump and oil from the oil supply tubes into the primary flow path. This releases oil into the core compressor upstream of the aircraft bleed ports contaminating the bleed air delivered to the Environmental Control System (ECS). This air is further distributed to the cabin and/or flight deck.

The duration of the smoke event following LRD activation depends on how long it takes for the affected engine to be shut down or the affected engine bleed system to be isolated. When the affected engine speed falls below a given core speed threshold (for instance, when engine automatically shuts down) the engine bleed will automatically be isolated and the smoke release will be stopped. If, however, the affected engine core speed does not immediately fall below the given threshold the isolation will depend on the application of the appropriate procedures by the flight crew. In this latter case, where engine bleed is not automatically isolated, it is crucial that the flight crew promptly applies the corresponding procedures that result in an engine shutdown, or a commanded isolation of the ECS bleed from the affected engine.

SIB recommendation for operators: 

• Operators provide their flight crew members with an identification of which aeroplanes in their fleet are equipped with CFM LEAP engines that include an LRD.
• In the event of engine severe damage or engine high vibrations, the flight crews should be prepared for a possible LRD activation and consequent dense smoke in the cockpit. 
• The above scenario is properly emphasised during flight crew conversion and recurrent training so that pilots are made aware of the challenges of an LRD event, so that flight crews may be aware of LRD activation consequences, and that appropriate mitigating actions may be implemented.

To access the SIB in full detail, visit the EASA Safety Publications Tool.