Light Sport Aircraft Zodiac CH-601XL should be grounded, says NTDB to FAA

The United States National Transportation Safety Board (NTSB) has issued an urgent safety recommendation to the United States Federal Aviation Administration (FAA) asking the FAA to ground the light sport aircraft (LSA) Zodiac CH-601XL.

The NTSB has made the recommendation because the single-engine, two-seat Zodiac CH-601XL has broken apart in flight as many as six times, in which 10 people have lost their lives since 2006.

The light sports plane Zodiac CH-601XL is made from kits sold by Zenith Aircraft Company, located in Mexico, Missouri, the United States. The Zodiac CH-601XL aircraft is sold in the United States and Europe.

In a statement, the National Transportation Safety Board said the latest fatality involving a Zodiac CH-601XL took place on March 3, 2009, when the aircraft broke
apart while it was cruising near Antelope Island, Utah, the United States.

The plane’s pilot died in the accident.

The Zodiac CH-601XL, according to the NTSB, is “susceptible to aerodynamic flutter,” a phenomenon in which the surfaces of the plane suddenly vibrate, and, if not checked, break the aircraft apart.

The Zodiac CH-601XL was certified as a special light sport aircraft by the Federal Aviation Administration.

This type of certification, the NTSB added, does not require that the FAA approve the airplane’s design but, instead, the aircraft model is issued an airworthiness certificate if the manufacturer asserts that the plane meets industry-accepted design standards and has passed the necessary ground and flight tests.

Mark Rosenker, chairman if the National Transportation Safety Board, explained in the statement that “the NTSB does not often recommend that all airplanes of a particular type be prohibited from further flight.”

In the case of the Zodiac CH-601XL aircraft, Rosenker added, “The NTSB believes that such action will save lives and that “unless the safety issues with this particular Zodiac model are addressed, we are likely to see more accidents in which pilots and passengers are killed in airplanes that they believed were safe to fly.”

The website amtonline.com quoted a spokeswoman of the Federal Aviation Administration as saying that the FAA had decided in February 2009 to set up a special team of experts.

The team would work with the US National Transportation Safety Board as well as with the aviation safety authorities in the Netherlands and Britain to determine
if there was a manufacturing defect or design problem with the Zodiac CH-601XL planes.

The US National Transportation Safety Board has cited the following six accidents involving the Zodiac CH-601XL plane since 2006:

1. On February 8, 2006, a plane crashed near Oakdale, California, after its wings collapsed. Two people died.
2. On November 4, 2006, a plane broke up in flight while cruising near Yuba City, California. Two people died.
3. On February 5, 2008, a plane crashed near Barcelona in Spain, after its wings folded up during a descent shortly before landing. Two people died.
4. On April 7, 2008, a plane broke up in flight near Polk City, Florida. One died.
5. On September 14, 2008, a plane crashed in the Netherlands. Two people died.
6. On March 3, 2009, the plane broke apart while it was cruising near Antelope Island, Utah, the United States. The plane’s pilot died.

Apart form the urgent recommendation to the Federal Aviation Administration on prohibiting further flights of the Zodiac CH 601XL plane, the National Transportation Safety Board issued the following seven additional recommendations to the FAA:

• Make a comprehensive evaluation of the wing and aileron system on the Zodiac CH 601XL plane to identify design and/or operational changes that will reduce the potential for flutter.

• Notify owners of Zodiac CH-601XL planes of any design and/or operational changes to the CH 601XL and require them to implement the changes.

• Work with ASTM International to incorporate standards for light sport airplanes that would reduce the likelihood of encountering in-flight flutter.

• Evaluate the stick force gradient at the aft center of gravity and especially at the higher Gs, and notify pilots of such effects.

• Develop standards on stick force characteristics for light sport airplanes that minimise the possibility of pilot’s inadvertently over-controlling the plane.
• Ensure that the pilot’s airspeed indicator reflects accurately the aircraft’s velocity and update pilot operating handbooks (POHs) accordingly.
• Work with ASTM International to ensure standards for light sport planes result in accurate airspeed indications and appropriate documentation in new airplane pilot operating handbooks.