a device and method for determining whether a no - back device is functioning properly includes a no - back device coupling an input shaft and an output shaft . a no - back output gear is coupled to the output shaft , and a reaction gear is operably coupled to the no - back output gear . a check device includes a rotatable drive feature having a first end accessible for rotation and a second end engaged with the reaction gear . the functionality of the no - back device is evaluated by applying a rotational torque to the drive feature .