The Question and Answer section for All My Sons is a great resource to ask questions, find answers, and discuss the novel.
Keller justifies his actions by claiming the incident was merely a mistake. Sending the cylinder heads was an accident.
Keller justifies what he did by claiming the faulty shipment was merely a mistake. Sending the cylinder heads was an accident.
Really it was Joe who demanded that the faulty airplane parts be sent. He justifies it to take the guilt off himself.
You need to submit each of your questions one at a time.