Winglets are a Good Thing – except when they demand counterproductive structural strengthening to overcome the additional wing stresses that they create. Today, that catch-22 no longer applies, thanks to Idaho-based Tamarack Aerospace Group, which has just received EASA certification for its Atlas system, which brings active gust-load alleviation technology to the world of non-fly-by-wire aviation.

Moreover, the first “production” upgrade has just been installed in a Swiss-registered Cessna Citation CJ1 operated by private charter firm JetPingu at Grenchen. The modification took 400 man-hours and was performed at the Textron Aviation service center in Zurich.

Tamarack secured STC approval for Atlas on the CJ1 and CJ1+ in January. Extension to the Citation M2 is pending; CJ3 and CJ2 are targeted next, while CJ4 is “on the radar.” Textron Aviation (Booth V029) has exclusive installation rights, the installation priced at US$219,000. Tamarack COO Brian Cox is looking forward to some 30 installations before the end of the year, assuming speedy parallel approval by the FAA.

Tamarack’s system adds small, aileron-like trailing-edge devices just inboard of the winglets. A turbulence sensor in the aircraft triggers the fly-by-wire active control surfaces, which deflect symmetrically to reduce the wing bending moment. As a bonus, the system also increases stability and improves ride quality.

Atlas functions automatically, independently of the aircraft’s flight controls. In the event of asymmetric failure, the pilot would counter with aileron input; the “cure” for total failure is just to slow down.

Where conventional passive winglets have to be “detuned” in size and shape to reduce the loads exerted on the wing structure, particularly in turbulence and steep turns, the active system “allows us to design and align the winglets in the most optimal shape and position,” says Cox.

Certification has followed a three-year development effort and more than 300 hr. with the company’s own CitationJet. “This is the first time Part 23 load alleviation has been certified,” says Cox. “Because we were the first to do this, we were subjected to the more rigorous Part 25 regulations. Trailblazing the path took longer than we expected.”—