Originally Posted by
onetrack
The FDR is designed to withstand an impact equating to approximately 310mph, but a vertical high-speed dive into relatively shallow water would cause serious damage to it.
A Silk Air 737 that dived in to the Musi River in Palembang was obliterated when it hit the water, but the FDR survived and was recovered with useable data. Google Silk Air MI 185. The aircraft nose dived from a similar flight level to MH 370.