Cessna is targeting a second-quarter first flight for its second and final M2 flight-test aircraft.
The programme is advancing toward certification in the second quarter of 2013.
As of 28 March, the first prototype had accumulated 21h of flight time on 12 missions since its first flight on 9 March.
The $4.2 million Williams International FJ44-powered twinjet, derived from the CJ1, is meant to be a step-up model between the entry-level $3 million Mustang and $7 million CJ2+.
"They've [Mustang owners] responded well to the aircraft," says Cessna's M2 business leader, Brian Rohloff. Data from Flightglobal Ascend shows 387 Mustangs in service globally as of 2 April.
As part of the US Federal Aviation Administration (FAA) and European Aviation Safety Agency (EASA) dual certification programme, the first aircraft will be used for engine compatibility, avionics and systems testing, while the second aircraft will be primarily used for aerodynamic testing, says Rohloff, adding that EASA validation is likely to lag behind FAA certification by three to four months.
Cessna plans to build M2 subassemblies at its Wichita plant and finish the aircraft at its Independence plant in Kansas, where the Mustang is built.
Current thinking is to have the M2 and Mustang in separate parallel lines at the start of assembly, merging into a single line at some point in the flow, says Rohloff.
He would not discuss the order book, but says the backlog "is right where we we're hoping it would be".