EASA is to permit Cessna CitationJets with activated Tamarack winglets to fly again if meeting the requirements of a service bulletin that incorporates specified modifications issued before the Emergency Airworthiness Directive (EAD) came into effect in April 2019. The lifting of restrictions comes in the form of an STC amendment that includes EASA Service Bulletin SB1480.

The new Service Bulletin requires that all Textron Aviation models 525, 525A, and 525B fitted with Tamarack's Active Winglet technology incorporate all existing product improvements. This allows compliant aircraft to resume flying normally.

“Tamarack made product improvements that enhance the safety and reliability of the Atlas active winglets available prior to the EAD. We are pleased that EASA has agreed that these improvements address the safety concern that prompted the EAD,” says Tamarack president Jacob Klinginsmith. “EASA and the FAA have been meeting regularly and we anticipate that the FAA will offer a solution to the limitations very shortly, in the spirit of the bilateral agreement in place between the agencies.”

SB1480 requires that the affected jets incorporate all existing product improvements, including SB1467, issued in April 2018, which enhances reliability of the TACS Control Unit (TCU), found to be at fault in an April 2019 incident preceding the EASA EAD.

SB1480 also requires that the affected jets incorporate SB1475, issued in March 2019, which consists of centring strips attached to the upper and lower trailing edge of the Tamarack Active Camber Surface (TACS). In the unlikely event of a system fault, the centring strips aerodynamically force the TACS back to their faired position, reducing the impact of the fault.

Tamarack founder and CEO Nicholas Guida adds: “I offer my sincere thanks to our loyal and supportive customers. They have been our staunchest advocates despite the inconvenience and hardship of having the use of their aircraft restricted. The resolution of the EAD is great news for Tamarack and its European customers.”

The FAA has approved a global Alternative Method of Compliance (AMOC) which also lifts those restrictions. The AMOC is an intermediate step meant to provide a way for the affected CitationJets to fly sooner than waiting for the final resolution of the AD, which will come later. Its provisions allow all US registered aircraft in compliance with Service Bulletin (SB)1480 to fly again without the AD's restrictions.

SB1480 requires all Textron Aviation jets fitted with Tamarack's Active Winglet technology (models 525, 525A, 525B) incorporate all previously approved system improvements, including SB1467, issued in April 2018, and SB1475, issued in March, 2019.

SB 1467 enhances reliability of the TACS Control Unit (TCU).

SB1475 consists of 'centering strips' attached to the upper and lower trailing edge of the Tamarack Active Camber Surface (TACS). The centering strips, in the unlikely event of a system fault, aerodynamically force the TACS back to their faired position, reducing the impact of the fault.

89 out of 91 of all aircraft equipped with the Tamarack's system are already in compliance with the requirements of SB1480.

“This AMOC will allow our customers to resume normal flight operations as quickly as possible,” adds Guida. “I am pleased to announce that we have booked three Active Winglet deposits during the FAA grounding, and we are scheduling new installations now. Tamarack is focused on the future and providing the most innovative and advanced winglet solutions in aviation.”