Paul Lewis/WASHINGTON DC
The Mitsubishi F-2A/B fighter programme has run into development problems with the discovery of fresh cracks in the wing during renewed static load testing by the Japan Defence Agency's Technical Research and Development Institute (TRDI).
TRDI flight testing of fourXF-2A/B prototypes has already slipped nine months as a result of earlier cracks found close to the aircraft's wingtip, along with excessive pylon flutter. The discovery of more fractures less than 12 months after the initial crack occurrence is being viewed "seriously", says an industry source.
It is understood the new cracks were found on a wing that had been structurally reinforced following last year's problems. The F-2 features a newly designed composite wing, 25% larger than that of the Lockheed Martin F-16 on which the Japanese fighter's development is based.
The Japanese Defence Agency (JDA)confirms that on 15 May during TRDI static load testing unusual noises were heard coming from the right hand wing. Ultrasonic and fibre-optic internal inspections revealed cracking and skin peeling around the fuel inlet in the centre of the right wing. The wing, one of two made for load tests, has been returned to Mitsubishi for analysis.
One wing last year exceeded its design load limit by around 135-140% before cracking, while the second only narrowly passed the 150% threshold margin before failing.
The F-2's outer wing has been internally strengthened and the first prototype recently returned to flight testing.
What impact this latest cracking will have is as yet unclear. Earlier delays had pushed back the end of XF-2 light testing to March 2000, but the first two production F-2s are nearing completion and are due for delivery in October.
The first operational squadron was due to have been formed at Misawa by March next year.
Source: Flight International
