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:
During a BCM (back-up control module) retrofit campaign, one resistor manufactured by SRT (Siegert) was found with an abnormal resistance drift. * * * * * * * *
When the aircraft is in control back up configuration (considered to be an extremely remote case), an incorrect value on these resistors may cause degradation of the BCM piloting laws, potentially leading to erratic motion of the rudder and to possible impact on the Dutch Roll [uncommanded coupling of airplane roll and yaw motions].
* * * * * The unsafe condition is erratic motion of the rudder could result in reduced controllability of the airplane due to dutch roll characteristics. The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.