Citing its failure to meet performance guarantees, Eclipse Aviation is modifying the design for its Eclipse 500 very light jet and offering customers reduced costs to compensate for late deliveries, some of which may not come until September 2007. As performance fell off the mark, Eclipse instituted a Performance Improvement Program which met the promised goal of 370 knots (TAS) and 1,125-nm range. The modifications are now undergoing certification which is expected between mid-March and mid-April.