Passive voice can only be used with transitive verbs. That is, verbs with both a subject and an object. In the passive voice, the original subject is removed and the object becomes the new subject.
She ate the apple. ("the apple" is the object that "she" ate)
The apple was eaten. ("the apple" is the subject that someone ate)
The verb "to perish" is not a transitive verb in American English, and in British English the transitive usage applied to a person means "to be made very cold", so you can't put "to perish" meaning "to die" into the passive voice. That is, in the sentence below:
The passengers perished. (no object that the passengers act on)
there is no object to be "promoted" to subject in the passive voice. Writing "The passengers were perished," would mean, "someone perished the passengers," which is a nonsensical use of the verb perish.
Even your first clause, "The plane was crashed," is strange. If the active form is "The plane crashed," then there is no passive equivalent because crashed is an intransitive verb and there is no object in this clause.
It is possible to use "to crash" as a transitive verb, but this is rare and surprising for a plane and we'd usually have some extra word(s) to express how strange this was.
The pilot deliberately crashed the plane. (here, "the plane" is the object)
The plane was deliberately crashed.
Again, the plane is moved from object to subject, and we have the word deliberately to emphasize that this is the unusual transitive meaning rather than the much more typical intransitive meaning.
It is grammatically acceptable to mix transitive and intransitive in the same sentence:
The plane was loaded with cargo and took off shortly thereafter.
Here we have the passive "was loaded" followed by the active phrasal verb "took off."