The district court entered summary judgment for defendants in this products liability case, which arises from the crash of an amphibious airplane. We must decide whether federal regulations pre-empt Dee's common law claims that an airplane seat was defectively designed even though the seat complied with federal design standards. Because federal law pre-empts none of Dee's claims, we vacate the district court's judgment.

Appellant William Dee was the sole passenger in an amphibious airplane manufactured or distributed by defendants Lake Aircraft, Inc., Aerofab, Inc., and Consolidated Aeronautics Inc. Dee sat next to the pilot. The pilot attempted to take off from a lake, but the plane crashed against a rock bank. Dee was seriously and permanently injured. The pilot suffered lesser injuries.

Dee sued defendants in negligence and strict liability. Dee claimed that defendants designed his seat in a negligent or defective way (or sold it in that condition) and that this defective design had enhanced Dee's injuries. Dee contends that his seat should have contained an "energy attenuating" mechanism to absorb crash forces. Dee says that the pilot's seat had an energy-absorbing feature: a cut-out portion containing laced rubber strips. Dee's seat, in contrast, was solid metal.

On defendants' motion for summary judgment, the district court ruled that Dee's state law claims were pre-empted by regulations promulgated under the Federal Aviation Act, 49 U.S.C.App. § 1301 et seq. Having found state law pre-empted, the district court allowed Dee to file further papers showing a genuine issue whether the aircraft violated federal design standards. Dee filed the affidavit of an expert witness, Dr. Snyder; but the district court found that Snyder's affidavit raised no genuine issue of violation of a federal standard.^[1] The district court entered judgment for defendants and dismissed Dee's action. This appeal followed.II. Pre-emption Analysis

The issue is whether Congress, in directing the Secretary of Transportation to promulgate federal aircraft design standards, intended to pre-empt the application of additional design standards arising under state tort law.

A. Aircraft Design: Federal Regulatory Background

1. Regulatory Authority. In the Federal Aviation Act of 1958 ("the Act"), codified as amended at 49 U.S.C.App. § 1301 et seq., Congress gave the Secretary of Transportation ("the Secretary") the authority and the duty to regulate aircraft safety, including the duty to promulgate "such minimum standards governing the design, materials, workmanship, construction, and performance of aircraft ... as may be required in the interest of safety." 49 U.S.C.App. § 1421(a) (1988). Congress created an inspection and certification system which enables the Secretary to enforce federal aircraft design standards.^[2] In the case of violations of federal regulations promulgated under section 1421 or of any term, condition or limitation of any certificate issued under the Act, the Secretary may assess civil penalties. 49 U.S.C.App. § 1471.

2. General Provisions. As originally enacted, the Act contained no provision expressly addressing federal pre-emption of state efforts to regulate civil aviation. In the Airline Deregulation Act of 1978 ("ADA"), Congress added an explicit pre-emption provision to the general provisions of the original Act. That section provides:

(a) Preemption

(1) Except [for certain Alaskan intrastate air transportation], no State or political subdivision thereof and no interstate agency or other political agency of two or more States shall enact or enforce any law, rule, regulation, standard, or other provision having the force and effect of law relating to rates, routes, or services of any air carrier having authority under subchapter IV of this chapter to provide air transportation.

49 U.S.C.App. § 1305(a). For background on the ADA amendments to the original 1958 Act, see H.R.Rep. 95-1211, 95th Cong., 2nd Sess. (1978), reprinted in 1978 U.S.C.C.A.N. 3737, 3752 (section 1305 intended to prevent states from filling void left by federal deregulation of airline operations with conflicting and inconsistent state regulations); Morales v. Trans World Airlines, Inc., --- U.S. ----, 112 S.Ct. 2031, 119 L.Ed.2d 157 (1992); Cleveland v. Piper Aircraft Corp., 985 F.2d 1438 (10th Cir.1993). The Act also contains a general "remedies" savings clause, which provides:

Nothing contained in this chapter shall in any way abridge or alter the remedies now existing at common law or by statute, but the provisions of this chapter are in addition to such remedies.

49 U.S.C.App. § 1506; see Morales, --- U.S. at ----, 112 S.Ct. at 2037 (Section 1506 is a "general remedies savings clause," and as a "relic of the pre-ADA/no pre-emption regime" does not supersede the specific pre-emption provision, section 1305.).

3. Federal Regulation of Aircraft Seat Design

The Secretary has promulgated "airworthiness standards" for aircraft. These regulations include design and construction standards. See 14 C.F.R. Part 23, Subpt. D, §§ 23.601-23.1203. Section 23.785 establishes design and performance standards for seats, berths, safety belts, and harnesses. Section 23.561 establishes general structural standards for emergency landing conditions.

The only mention of "energy absorbing" designs in the seat design regulations, at the time of the events in this case, was in § 23.785(j). Subsection (j) said:

The cabin area surrounding each seat, including the structure, interior walls, instrument panel, control wheel, pedals, and seats, within striking distance of the occupant's head or torso (with the safety belt harness fastened), must be free of potentially injurious objects, sharp edges, protuberances, and hard surfaces. If energy absorbing designs or devices are used to meet this requirement they must protect the occupant from serious injury when the occupant experiences the ultimate inertia forces prescribed in § 23.561(b)(2).

14 C.F.R. § 23.785(j) (1984) (emphasis added). Thus, although federal regulations recognized energy absorbing features as design options, no provision required that aircraft seats contain an energy absorbing device to be certified as "airworthy."

At the time of the crash, the aircraft in which Dee was injured had a valid airworthiness certificate, which certified, among other things, compliance with federal design regulations. 49 U.S.C.App. § 1423(a),(c).

In this case, we must determine whether Congress intended, in directing the Secretary to promulgate minimum standards for safe airplane design, to supersede state law on that same subject. If Congress intended to pre-empt state law, the Supremacy Clause, U.S. Const., Art. VI, cl. 2, dictates that the state regulations must yield.

Pre-emption may be either expressed or implied, and is compelled whether Congress' command is explicitly stated in the statute's language or implicitly contained in its structure and purpose. Absent explicit pre-emptive language, [the Supreme Court has] recognized at least two types of implied pre-emption: field pre-emption, where the scheme of federal regulation is so pervasive as to make reasonable the inference that Congress left no room for the States to supplement it, and conflict pre-emption, where compliance with both federal and state regulations is a physical impossibility, or where state law stands as an obstacle to the accomplishment and execution of the full purposes and objectives of Congress.

Gade v. National Solid Wastes Management Ass'n, --- U.S. ----, ----, 112 S.Ct. 2374, 2383, 120 L.Ed.2d 73 (1992) (citations and internal quotation marks omitted). Federal law may pre-empt state common law rules in the same ways as state statutes or regulations. Cipollone v. Liggett Group, Inc., --- U.S. ----, ----, 112 S.Ct. 2608, 2621, 120 L.Ed.2d 407 (1992); Papas v. Upjohn Co., 985 F.2d 516, 517-18 (11th Cir.1993). "The purpose of Congress is the ultimate touchstone of pre-emption analysis." Cipollone, --- U.S. at ----, 112 S.Ct. at 2617.

The district court ruled that Dee's claims were impliedly pre-empted by federal regulations. But where Congress has with words pre-empted some kinds of state lawmaking, courts are cautious about relying on implied pre-emption theories to limit state authority further.

When Congress has considered the issue of pre-emption and has included in the enacted legislation a provision explicitly addressing that issue, and when that provision provides a reliable indicium of congressional intent with respect to state authority, there is no need to infer congressional intent to pre-empt state laws from the substantive provisions of the legislation. Such reasoning is a variant of the familiar principle of expression unius est exclusio alterius: Congress' enactment of a provision defining the pre-emptive reach of a statute implies that matters beyond that reach are not pre-empted.... Therefore, [courts] need only identify the domain expressly pre-empted by each of those sections.

Cipollone, --- U.S. at ----, 112 S.Ct. at 2618.^[3]

In this case, section 1305 reliably indicates Congress' intent on state authority to regulate civil aviation. See Cleveland v. Piper Aircraft Co., 985 F.2d 1438, 1443-45 & n. 17 (10th Cir.1993).^[4] Section 1305 pre-empts state laws "having a connection with or reference to airline 'rates, routes, or services.' " Morales v. Trans World Airlines, Inc., --- U.S. ----, ----, 112 S.Ct. 2031, 2037, 119 L.Ed.2d 157 (1992). Under Cipollone, we conclude from section 1305 that Congress did not intend to pre-empt state laws on matters unrelated to airline rates, routes or services.^[5] Because Dee's design defect claims lie outside the pre-emptive reach of section 1305, we conclude that those claims are not pre-empted.

The judgment of the district court is VACATED, and the case is REMANDED for further proceedings consistent with this opinion.