Statistical Process Control Based on Gamma-Frailty AFT Models // Implements statistical process control ('SPC') monitoring schemes for heterogeneous reliability observations using Accelerated Failure Time ('AFT') models integrated with continuous gamma frailty. It accommodates both uncensored and right-censored reliability observations in the presence of observed and unobserved covariates. Provides Phase I maximum likelihood estimation of Weibull 'AFT' gamma frailty model parameters, and Phase II monitoring procedures including probability-limits-based control charts, exponentially weighted moving average ('EWMA') charts with conditional expected values, and likelihood-ratio cumulative sum ('CUSUM') control charts. Competing 'CUSUM' schemes (ignoring unobserved frailty or both covariates) and Average Run Length ('ARL') simulation utilities are also provided. The statistical methodology is based on Asadzadeh (2022) doi:10.1080/00949655.2021.1959582.