The versatile, small utility, business and private aircraft often operates from strips where external power and engine preheat are not available. Starting tests performed at 0 F have shown that with all engine conditions normal (standard SAE 30 aircraft engine oil, external power source, and functioning prime system), an engine start is unlikely. Faster cranking speeds are known to contribute substantially to improved starting, and can be obtained through the use of less viscous lubricating oils. An SAE 10W30 aircraft engine oil, compounded to promote easier cold weather starting and offering adequate protection at normal operating temperatures, is discussed and comparisons are drawn between this oil and other available multiviscosity oils. Results from cold weather starting tests as well as a service test program performed to support the use of the 10W30 oil under normal hot weather operating conditions are presented.