Jury Finds 'Defect' in Eurocopter AS350B3 Flight Control System

Here we go again... despite specific NTSB findings to the contrary, a TX jury has decided that a 'defective flight control component caused the fatal crash of a U.S. Custom and Border Protection (CBP) Eurocopter AS350B3 helicopter (see file photo) on May 22, 2007.'

According to a 'press release' sent ANN by a Dallas PR firm, Dallas area aviation attorney Jon Kettles and El Paso attorney Enrique Moreno represented the widow of the pilot killed in the accident and reportedly assert that, "The two-week trial centered on claims by the pilot's family and the injured crewmember that a manufacturing defect in a flight control servo made the aircraft uncontrollable and caused the crash during a routine border security mission."

Defendants, Eurocopter and Goodrich, contended that the accident was caused by the pilot entering vortex ring state. They have good reason to believe so, since the NTSB concluded the same thing on December 28th of 2008.

The NTSB found the Probable Cause for the accident to have been, "The pilot's encounter with a vortex ring state and his inability to maintain control of the helicopter."

While the report does note damage to the flight control system as a result of the crash, the published report does not seem to indicate that anything but the vortex ring state encounter as causal to this sad accident, in which the pilot was killed and another crewmember was critically injured.

The NTSB report states that, "A fully developed vortex ring state is characterized by an unstable condition where the helicopter experiences uncommanded pitch and roll oscillations, has little or no cyclic authority, and achieves a descent rate, which, if allowed to develop, may approach 6,000 feet per minute. It is accompanied by increased levels of vibration. A vortex ring state may be entered during any maneuver that places the main rotor in a condition of high upflow and low forward airspeed. This condition is sometimes seen during quick-stop type maneuvers or during recoveries from autorotations. The following combination of conditions are likely to cause settling in a vortex ring state: 1. A vertical or nearly vertical descent of at least 300 feet per minute. (Actual critical rate depends on the gross weight, rpm, density altitude, and other pertinent factors.) 2. The rotor system must be using some of the available engine power (from 20 to 100 percent). 3. The horizontal velocity must be slower than effective translational lift.”

Of course, in this case, a TX Jury seemed to know better... despite the fact that the NTSB employs some of the best aircraft accident investigators in the world, and in our experience, has particularly talented folks among its rotorcraft investigations staff.

FMI: http://www.ntsb.gov/aviationquery/brief.aspx?ev_id=20070530X00664&key=1