Story ID: 
Tamarack Disputes NTSB Accident Report
By: Curt Epstein
Caption: Tamarack Aerospace is disputing the NTSB’s final report on fatal crash of a Citation CJ2+ which went down soon after takeoff in Indiana in November, 2018.
Word Count: 246
Tamarack Aerospace is disputing the NTSB’s final report regarding the fatal crash of a Cessna Citation CJ2+ outfitted with its active winglets. The twinjet went down soon after takeoff from Indiana's Clark Regional Airport on Nov. 30, 2018, killing the pilot and two passengers.

The CJ2+ was equipped with Tamarack’s Active Technology Load Alleviation System (ATLAS), which includes aerodynamic control surfaces mounted on the wing extensions that either hold their position in trail with the wing or symmetrically deploy trailing edge up or down to alleviate structural loads.

According to the NTSB, the accident's probable cause was “the asymmetric deployment of the left-wing load alleviation system for undetermined reasons, which resulted in an in-flight upset from which the pilot was not able to recover.” Last week, Tamarack countered the NTSB’s determination by issuing a supplemental submission stating that its investigation of the physical crash evidence proved that the system was functional at the time of the crash. It noted that the accident sequence showed that the Citation’s autopilot disconnected at a bank angle less than its expected extreme range of functionality.

Tamarack is proposing an alternate scenario where the attitude and heading reference system/autopilot failed, leading to the onset of the initial roll event that doomed the light jet. The company said it plans "to request the NTSB reconsider its finding, as per its own procedures," which refers to the NTSB's "petition for reconsideration" process.