use of indefinite article

[mikhai]

Why can't we use indefinite article with attribute+personnel (e.g., a good personnel), if we can say a+attribute+crew/company, etc.

[sarat_106]

Why can't we use indefinite article with attribute+personnel (e.g., a good personnel), if we can say a+attribute+crew/company, etc.

You can not say a attribute crew/company. Attribute is a countable noun and is also used as verb, where as personnel is plural noun. These two nouns do not combine to form a compound word, attribute personnel, as mentioned by you. You can use an article (both indefinite and definite) before attribute.
The love for all living creatures is the most noble attribute of man.