tween Moon Lake’s poles, Mountain States installed two of its own poles (pole nos. 3 and 4), one on each side of the river, creating a shorter span for the telephone lines. The telephone lines thus spanned the river approximately thirty feet below the Moon Lake power lines. The Moon Lake power lines were not attached to the new poles, but continued to span the 1007-foot distance between Moon Lake’s poles.
This configuration remained in place for eighteen years, until the accident in 1982. There had been no previous incidence of aircraft colliding with any of the wires. The accident site is located in a remote area of Utah that is not within any regularly traveled flight path and is ten miles from the nearest air strip.
Mr. Shute testified that as the helicopter approached the accident site, he was able to observe Mountain States telephone wires which were Vio-inch thick and had taken on a dark color. He also testified that he observed each of the poles between which the power lines and telephone wires were suspended. However, Mr. Shute testified that he was unable to see the silver colored Moon Lake power lines that were suspended 30 feet above the telephone lines and not attached to the shorter Mountain States poles (3 and 4). As he approached the line crossing, Mr. Shute observed the five visible poles and assumed that both sets of wires were attached to all the poles. Accordingly, Mr. Shute assumed that by climbing to an elevation high enough to clear the two poles closest to the river (Mountain States poles 3 and 4 to which only the telephone lines were attached), he would safely clear all wires. The helicopter gained sufficient altitude that it cleared the telephone wires, but it struck the Moon Lake power lines that were suspended above the telephone lines. The collision caused the power lines to act as a tether around the helicopter’s rotor mast and the helicopter crashed, injuring Mr. Shute and destroying the helicopter.
Plaintiffs brought this action against Mountain States and Moon Lake claiming that the two were negligent in the design and maintenance of the wire configuration at the accident site. The defendants argued that the accident was due to Mr. Shute’s negligence in piloting the helicopter. The jury returned a verdict apportioning negligence to the various parties as follows: Mr. Shute 8%, Moon Lake 32%, and Mountain States 60%. Prior to the entry of judgment on the verdict, Moon Lake settled with the plaintiffs and is not involved in this appeal.
Mountain States now argues that the district court erred in not awarding Mountain States judgment as a matter of law because Mountain States owed no duty to the plaintiffs either in the construction or maintenance of the wire configuration. Mountain States also challenges the judgment on the ground that there was not sufficient evidence for the jury’s verdict and on the further ground that the trial court erred in giving its instructions to the jury on the issue of negligence. For the reasons discussed below, we affirm the judgment of the district court.
II. Duty
Mountain States based several motions, including motions for summary judgment and for directed verdict, primarily on the claim that it owed no duty to plaintiffs and thus cannot be held liable for negligence. In determining whether the district court was correct in denying the motions, we must decide whether Mountain States owed a duty to plaintiff.
Because federal jurisdiction here is based on diversity under 28 U.S.C. § 1332 (1982), we must apply the substantive law of the state in which the accident occurred, in this case Utah law. See Erie R.R. Co. v. Tompkins, 304 U.S. 64, 58 S.Ct. 817, 82 L.Ed. 1188 (1938); Rigby v. Beech Aircraft Co., 548 F.2d 288, 290 (10th Cir.1977). Applying Utah law, we agree with Mountain States’ assertion that in order to recover based on negligence, a plaintiff must show that the defendant owed a duty to that plaintiff. See Weber v. Springville City, 725 P.2d 1360, 1363 (Utah 1986). The question of whether a duty exists is a question of law for the court to decide. Id. Accordingly, we review de novo the duty issue.