Final answer:
Zero timing an engine refers to the complete overhaul or rebuilding of an engine to factory new limits, resetting its operational life. In context with the air conditioner maintenance question, allocating 1.1 hours per technician for the inspection and maintenance may not be sufficient due to the variability indicated by the standard deviation of one hour.
Step-by-step explanation:
When an engine has been zero timed by the manufacturer, it indicates that the engine has been completely overhauled or rebuilt to factory new limits. In essence, the engine's operational life is reset, as if it were a brand-new engine, even though the parts may be reused after inspection and reconditioning. This process ensures that the engine meets all original manufacturer specifications, effectively making it equivalent to new in terms of operation and performance. The purpose of zero timing an engine may include ensuring reliability, safety, and maintaining the value of the aircraft. After such a procedure, a detailed inspection is crucial to certify the workmanship and integrity of the overhaul.
Concerning your company's situation, planning to budget an average of 1.1 hours per technician for future inspections and service visits might not be sufficient. Considering the average service time is one hour with a standard deviation of one hour, this means that approximately 68% of the servicing should fall between 0 and 2 hours to be within one standard deviation. Since there can be significant variability in the time it takes for technicians to service AC units, allocating 1.1 hours per technician might be too optimistic, especially for units that may require more extensive servicing.