Authorities clear light jet for flight testing following inspection in wake of November's fatal accident to prototype.

Grob Aerospace is aiming to achieve certification of its SPn light business jet in the first quarter of next year as flight testing of the first prototype resumes after a three-month freeze.

The German civil aviation authority gave the thumbs-up to Grob late last month upon completion of the 300h maintenance check and aircraft inspection. This was imposed following the crash in November last year of the second prototype SPn during a demonstration flight at the company factory in Tussenhausen-Mattsies, Germany. The manufacturer's chief test pilot was killed in the accident.

The preliminary factual report cited elevator flutter leading to the separation of parts of the control surface and of the horizontal stabiliser as a focus for accident investigators.

The first SPn prototype had its first flight in July 2005 and has logged around 300h and 454 cycles. The aircraft, which has undergone a number of modifications including the fitting of a belly fairing and larger ailerons, will be used for systems and performance testing, says Grob.

The aircraft will be joined in the second quarter by the third prototype, which is being built to the same aerodynamic standard as the second test aircraft. A fourth prototype is now in its early stages of construction and will be followed by the first production aircraft, which will be used for function and reliability testing.

"Having the aircraft flying reconfirms to the industry that we are still confidently on the road to European and US certification, for the first and second quarter of 2008 respectively," says Grob chief executive Niall Olver.

Source: Flight International