Is there really such a thing as a "voidance apron"?

Question

"I worked it out. You know the pilot? We thought he was shouting avoidance apron. But he wasn't. I heard one of the ladies here. He wanted a - voidance apron. She called it a sh*t-wrap." Richard laughed stealthily, under the cover of his shaking shoulders. He did think it was kind of great. You wouldn't want to radio ahead for a ****-wrap. That would offend the passengers. So you radioed ahead for a "voidance apron."...

An excerpt from The Information by Martin Amis

Answer 1

and stay away please:)

Answer 2

Please go away.  Thanks.