London Ontario-based Diamond Aircraft says the first flight of its second D-Jet, this one built using production tooling, will take place before the end of August, four months later than originally planned, kicking off a certification effort the company expects to lead to first deliveries of the $1.4 million, five-seat personal single-engined jet next year.

"We made the decision to accept a later s/n 002 first flight to commit to production quality tooling to produce this first of four prototypes that will be used in the flight-test certification programme," said Peter Maurer, company president, in the first edition of the D-Jet Flyer newsletter published in July.

"The benefit will be a smoother transition from prototype build to series production, and a reliable delivery schedule."

D-Jet s/n 001, which first flew last April, was not "100% aerodynamically conforming", says Maurer, meaning "definitive" performance measurements were not possible in the more than 100 ground and flight tests accomplished. "We have a high degree of confidence on performance based on what we've seen," he adds.

The proof-of-concept aircraft was used to prove the Williams FJ33-4 engine and Garmin G1000 avionics (with two 12in (305mm) primary flight displays and a centre 15in multifunction display) integration, the aerodynamic optimisation of ventral strakes, wingtips, engine fairing and the wing/fuselage interface, in addition to the flight-control optimisation and an improved braking system.

Maurer says the primary purpose of s/n 002 will be validate the aerodynamic configuration, with and without winglets, handling qualities, stability and control performance and engine operations.

S/n 003 will be dedicated to systems development and certification s/n 004 for electrical and avionics system, autopilot and de-icing system development and s/n 005 will be a fully conformed prototype with a production interior. The company will also built non-flying prototypes for full-scale static structural testing.

Diamond currently has more than 300 orders for the aircraft, with most delivery positions sold out until 2010.