Different parts of the - ahem - vehicle will see vastly different g-loads.
The pointy end stops VERY quickly, ergo by definition very high acceleration loads. The tail end is cushioned by the collapse of everything in front, so it sees much lower loads - thus they install the FDR, CVR etc back there to improve the likelihood of them surviving. (75-80 years ago the pilot might be back there too - my how far we've progressed!
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