Final answer:
Damage to the MB-1 tie-down/chain assembly that warrants replacing the assembly includes heavy rust, surface breakdown, cracking, and flaking of the metal.
Step-by-step explanation:
Damage to the MB-1 tie-down/chain assembly that warrants replacing the assembly includes heavy rust, surface breakdown, cracking, and flaking of the metal. For example, if the chain is continuously exposed to moisture and salt spray, rust can form on the links leading to weakening and potential failure of the assembly. Similarly, surface breakdown, cracking, and flaking of the metal can compromise the integrity of the assembly and make it unsafe for use.