Change of Tour Routes Blamed for Grand Canyon Air Collision

A decision to shift some sightseeing routes because of complaints about noise set the stage for the collision of two aircraft full of tourists over the Grand Canyon last summer, a federal safety board concluded Tuesday.

The National Transportation Safety Board said the primary cause of the June 18, 1986, accident, which claimed 25 lives, was that neither pilot saw the other aircraft, although it was a clear day.

The safety board also said that an important contributing factor was the decision last April to shift the aerial sightseeing routes that helicopter tours were using.

The change caused the Helitech Inc. sightseeing helicopter to fly in a wider arc, about three miles farther west and intersecting the usual routes of Grand Canyon Airlines, another sightseeing operator, investigators said.

The collision of a Helitech helicopter, carrying four tourists and the pilot, and a Grand Canyon Airlines DeHavilland Twin Otter, with 18 passengers and two crewmen aboard, occurred where the routes intersected under the altered flight plans.

Routes Were Separated

Both companies usually operated at altitudes allowing for separation of about 500 feet. The collision occurred at about 6,500 feet.

Barry Strauch, a safety board staff investigator, said that while there was no formal government requirement that the routes be changed, sightseeing tour operators did so on April 1, 1986, because of pressure from the National Park Service, which for years has received complaints about helicopter noise in the canyon.

“The flight operators felt that the National Park Service would seek legislation to restrict their movement” if they did not voluntarily shift routes to ease the noise problem, Strauch said.

Had the routes not been changed, the Twin Otter and the helicopter would have been flown in a wide, counterclockwise arc over the canyon. On the return trip, they would have followed roughly parallel paths a mile or more apart in the area where the collision occurred, according to the investigation.

Change Led to Accident

While the route change may have been made for good reasons, “the policy did increase the danger, which matured into an accident in this situation,” safety board Chairman Jim Burnett said after the board adopted the report on the aerial collision.

Under the unofficial pressure applied to the tour operators, the route change did not undergo close scrutiny in relation to safety, Burnett said.

In the formal report, the safety board criticized the Federal Aviation Administration for failing to “exercise its oversight responsibility,” because FAA inspectors responsible for Grand Canyon Airlines had raised no concern about the route change.