Honda Aircraft says today that certification of the HA-420 HondaJet is delayed by roughly one year to late-2014 as development of the light jet's all-new engine continues to fall behind schedule.

As of October, the five-passenger HA-420 was supposed to be delivered to customers by late 2013, or several months after the Honda/General Electric HF120 completed its own certification process this month.

But Honda Aircraft now reveals that the 2,000lb-thrust (1,400kW) HF120 will not achieve certification until the end of this year. When asked why the engine did not clear the certification milestone as scheduled, Honda Aircraft declined to offer specifics.

"They still have testing that they're going to complete," Honda says.

It was always ambitious for Honda Aircraft to develop a new airframe and new propulsion simultaneously for its first flying product. Most aircraft manufacturers choose to develop one or the other at a time.

Development of the HF120 has been particularly difficult. The turbofan failed a critical ice slab test in a certification trial in February 2011, which delayed the project by one year already.

So far, Honda Aircraft has built four flying prototypes, of which three are involved in early flight tests.

The new certification delay comes after Honda Aircraft launched serial production of the HA420 last October.

The HA420 features an unusual over the wing engine mounting for its pair of HF120 turbofans, which the company claims reduces drag. The design of the wing and nose is also optimised for channelling the airflow smoothly over the surface of the aircraft to generate lift most efficiently.

Honda Aircraft expects that combination of features to deliver a 30kt-speed improvement over the rival Embraer Phenom 100.

Source: Flight International