ShinMaywa Industries has delayed the first flight of the modernised US-1A Kai search-and-rescue amphibian until at least September to replace the boundary layer control engine duct.

The Japanese company says the duct in the first production prototype has become clogged and needs replacement, which will not be completed until late this month or early September.

ShinMaywa says some minor technical issues also have to be resolved and technical data collection has to be completed before the aircraft is cleared to fly. Its first flight was scheduled for this month, but ShinMaywa now expects a first take-off in September or October.

The Mitsubishi Heavy Industries boundary layer control system is a key driver in the four-engined US-1AKai's expected performance improvement over the US-1A. The new aircraft is expected to fly twice as high (at 20,000ft/6,100m), 40kt (74km/h) faster (at 270kt) and take off from water more than 50% quicker than the US-1A.

ShinMaywa has built 19 US-1As over the past three decades, seven of which are still in service. Japan intends to keep a fleet of seven, but gradually switch to the Kai from 2006.

Rolls-Royce AE2100J engines replace General Electric T58s, while a pressurised upper hull also contributes to the Kai's performance improvement. Shin- Maywa has started engine runs.

The Japan Defence Agency (JDA) has ordered four prototypes, two for flight testing and one each for static and fatigue testing. ShinMaywa expects to perform approximately 100h of flight testing before delivering the prototype to the JDA in March. Around half the flights will be conducted from the sea next to its Kobe factory, and the other half from Iwakuni air base.

Source: Flight International