Summary
We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:
It was discovered that the Horizontal Stabilizer Trim Actuator (HSTA) No Back and the Number 1 Motor Brake Assembly (MBA) can both fail dormant. A failure of the HSTA No Back and the Brake System along with additional component failure could result in an uncontrollable horizontal stabilizer surface runaway without the ability to retrim. This condition, if not corrected, could lead to the loss of the aeroplane. * * * * *
The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.