Here are some references that addresses the feature selection regarding prognostics.
There are many approaches that addresses this topic. You can find a lot of metrics to assess the "prognoticability" of your features. You can calculate metrics such as: Monotonicity , Prognosability , and Trendability defined in this paper: Coble, J., & Hines, J. W. (2009, September). Identifying optimal prognostic parameters from data: a genetic algorithms approach. In Annual conference of the prognostics and health management society, san diego, ca, september. http://ftp.phmsociety.org/sites/phmsociety.org/files/phm_submission/2009/phmc_09_69.pdf
Or separability criteria defined in this paper:
Medjaher, K., Camci, F., & Zerhouni, N. (2012, July). Feature extraction and evaluation for Health Assessment and Failure prognostics. In Proceedings of First European Conference of the Prognostics and Health Management Society, PHM-E'12.
Or go further with feature fusion, in this paper:
Atamuradov, V., & Camci, F. Evaluation of Features with Changing Effectiveness for Prognostics.