Adam Aircraft has made "minor modifications" to the all-composite piston twin A500 as it works towards US certification in the third quarter.
The second prototype has been modified with winglets and an airstair door, and was due to be pressurised last week.
The winglets have been fitted to eliminate the potential for fuel spills when the aircraft is parked on an incline. The fuel vents have been relocated from the wing to the tips of the winglets.
Source: Flight International