In Boyle v. United Techs. Corp., 487 U.S. 500 (1988), a United States Marine drowned after a helicopter crash and his estate sued the helicopter's designer, a military contractor, claiming that the helicopter's emergency escape hatch was defectively designed. Id. at 502. The Court held that: liability for design defects in military equipment cannot be imposed, pursuant to state law, when: (1) the United States approved reasonably precise specifications; (2) the equipment conformed to those specifications; (3) the supplier warned the United States about the dangers in the use of the equipment that were known to the supplier but not to the United States. Id. at 512. Boyle involved a separate exemption to the waiver of immunity provided in the FTCA for discretionary governmental functions. See id. at 511 (citing 28 U.S.C.A. 2680(a)).