Sterling Aviation Technologies has received an STC for an elevator spar replacement kit for the Commander Model 112/114 airplanes.
Fatigue cracks found in elevator spars prompted the FAA to issue AD 2012-02-10, which requires periodic spar inspections. If fatigue cracks are found, the spar must be replaced.
“Several years ago we became aware of an Airworthiness Directive for the Commander 112/114 that addressed fatigue cracking of the elevator spars. After a lot of research we determined the cause of the fatigue cracking and decided to re-design the spar and outboard elevator hinge,” officials said on the company’s website. “The new design eliminated the cause of the cracking and resulted in the FAA issuing a AMOC (Alternate Means Of Compliance) letter that eliminates the inspections required by the Airworthiness Directive. We have completed our first production run of the new spars and hinges and are now making them available to Commander owners.”
Fatigue analysis shows that the new spars have a fatigue life that is several times the expected fatigue life of the airframe, company officials added.
The Elevator Spar Replacement Kit is $5,000.