Multi-parameter influence on deceleration performance of ejector system for emergency flight data recorders

In the event of an aircraft crash over the ocean, the potential risk of the Flight Data Recorder (FDR) system sinking to the ocean in conjunction with the aircraft debris is substantial, which would significantly complicate search and rescue operations. To mitigate this challenge, a separable flight data recorder has been developed by our team which called Emergency Flight Data Recorder (EFDR) system. Encapsulated within a cushioning airbag, the recorder is ejected from the aircraft and decelerates to the sea surface via a deceleration parachute, enhancing both the efficiency of search and recovery operations and the feasibility of flight data analysis. This paper presents an experimental study on the ejection velocity of the ejection system in the EFDR framework, focusing on three critical parameters: airbag material, deceleration parachute placement, and flight data recorder weight. The experimental results indicate that encapsulating the device in an airbag reduces ejection velocity, with fabric airbags inducing a smaller velocity decrement compared to rubber counterparts. Additionally, the deployment of a deceleration parachute further decreases ejection velocity, with a more pronounced reduction observed when the parachute is positioned in front of the projectile than when placed at rear. However, this velocity penalty is deemed acceptable due to the enhanced reliability of parachute deployment in the anterior configuration. Within the counterweight weight range of 2–6 kg, ejection velocity exhibits a marginal decrease with increasing weight, suggesting that variable payloads have a negligible influence on ejection performance. These findings provide empirical insights for the subsequent design optimization of the EFDR system.