Mitsubishi Aircraft says the latest slip in the first flight schedule of its MRJ regional jet does not represent “major trouble” in the programme.

In response to queries from Flightglobal, the Japanese manufacturer explains that in ground tests conducted thus far, “a bug” has occurred in a portion of its software. Design changes also had to be made to some system parts.

“In considering these issues in detail, we looked at feedback on the airframe software and hardware. One specific example of this feedback is a problem with the degree of ram-air turbine structural strength,” says a spokeswoman.

“These are, however, problems that arise as a normal part of the aircraft development process. They do not, at any rate, represent the kind of major trouble that would cause a delay in the overall schedule.”

Last week, Mitsubishi announced that the first flight of its regional jet has been pushed back to September or October of 2015, from the second quarter. It explained that the first flight schedule has been delayed so as to “fully incorporate the verification results” of various tests into the first flight test aircraft.

In January, Mitsubishi started full-scale tests and also performed a first engine run on aircraft MSN 10001. It has since performed various ground tests including functional and performance tests for devices of its avionics, hydraulics, air conditioning, lighting and landing gear systems. It has also conducted ground vibration tests, electromagnetic tests, safety tests and taxi tests.

Asked if there are further tests that need to be done before first flight, or which it is behind schedule on, the manufacturer declined to comment.

Mitsubishi adds that the programme’s development schedule has been restructured “to conduct timely consideration and feedback of all test results to improve the flight test data density”. To keep to its second quarter 2017 delivery schedule, the airframer says it will send four instead of three aircraft to the United States for flight tests, which will also be done on a more “frequent” basis.

Going forward, Mitsubishi says it will collaborate in closer partnership with Mitsubishi Heavy Industries on operations with the advancement of the programme. It adds that it is keeping its customer airlines “very closely informed” in its development, and that progress will be periodically disclosed publicly.

This is the fourth delay to the programme that Mitsubishi has announced over the years. Flightglobal’s Ascend Fleets database shows that there are 223 firm orders for the MRJ, as well as 164 options and 20 letters of intent.

Source: Cirium Dashboard