@deptrai
I'm imagining an ELT that gets "armed" in cruise, autonomously detects unusual bank angles, AOA, ground speed, sink rates, or combinations thereof (can be done with cheap gyros and GPS), and that can separate itself from an airframe and parachute to the surface of the earth, preferably with a copy of voice and flight recorder data.
Those systems already exist and certified, for decades!
They are known by various names such as Crash Position Indicators (CPI), Deployable Flight Incident Recorder Set (DFIRS) or Automatically Deployable ELT (ADELT).
Modern versions do combine CVR and FDR data along with locating capability. They are primarily used on military aircraft but are also common on civilian helicopters operating long distances over water or at remote locations.
Older designs did use parachutes although most nowadays rely on the ability to withstand impact at terminal speed.
They usually have multiple crash sensors and will automatically release when detecting large g-forces, deformation of frangible sensors, submersion in water, etc. Most can also deployed manually.
Here's a version from the 1970s:
IEEE Canada - The Crash Position Indicator
Story about a recovered F-18 DFIRS:
http://www.defensemedianetwork.com/s...e-home”/