A certificated parachute rigger cannot exercise privileges unless?

The correct answer highlights the importance of hands-on experience and proficiency in parachute packing for a certificated parachute rigger. The requirement for a rigger to have packed at least one parachute within the last month ensures that the rigger maintains their skills and is familiar with any new developments in packing techniques or equipment. This practical experience is crucial for safety and efficacy, as parachute rigging requires that the rigger is intimately familiar with the current tools and methods.

While understanding the manufacturer's instructions is important for safety and compliance, it does not replace the need for recent practical experience. Similarly, while a letter of recommendation from a Master Rigger and attending a refresher course can contribute to a rigger's qualifications, they do not directly ensure that the rigger remains proficient in the essential task of packing parachutes, which is fundamental for the safety of skydivers and the effective operation of parachute systems. Thus, maintaining recent hands-on experience is vital and clearly outlined in the requirements for certificated parachute riggers.