Mecha Grunty is a repeatable field encounter, and by field I mean by using three words to go to an area (as opposed to a Guild @Home like Kestrel, a Lost Ground like the Hulle Granz Cathedral, or a Root Town like Mac Anu). The poor machine will have exhausted its fuel supply and will plead with you for Chimspheres. The amount it requests will increase with every encounter. Refueled, it will suit up, shoot off, and crash elsewhere. Your kindness will be rewarded in the way of small trinket items (like recovery items most times) and you only need to do this five times for this trophy, though there is ample reason to continue helping it (for the Mecha Grunty quest and its rewards).