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:
A change in dimensions of the fuse blocks in the Auxiliary Power Unit (APU) Start Contactor Assembly (ASCA) box assembly can cause an incorrect interface between the bus bars and fuses. This condition can result in an increase in temperature, which could damage the ASCA box and/or compromise the availability of battery bus supply.
The unsafe condition could result in the ignition of a fire in the ASCA box. The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.