Premise: The Robinson R44 is a four-seat light helicopter produced by Robinson Helicopter Company since 1992. Based on the company's two-seat Robinson R22, the R44 features hydraulically assisted flight controls. It was first flown on 31 March 1990 and received FAA certification in December 1992, with the first delivery in February 1993.
Hypothesis: It took three years for the Robinson R44 to receive certification from the FAA from the time it was first flown until the time certification was granted.