Failure to De-Ice Wings 2nd Time Cited in Crash : Continental DC-9 Waited Too Long in Snowstorm to Take Off From Denver Last Year, NTSB Says

The captain’s failure to de-ice his plane a second time while waiting in a snowstorm for takeoff was the principal cause of a Continental Airlines crash at Denver last November that killed 28 of the 82 aboard, federal investigators said Tuesday.

The National Transportation Safety Board, which conducted a 10-month investigation into the takeoff crash of Flight 1713, said the inexperience of the captain and his co-pilot--who was actually flying the plane--and confusion between air traffic controllers and the flight crew were both contributing factors in the accident.

The board also focused on the training record of the co-pilot, who had been fired by an air taxi company in 1985 after failing three times to pass his flight examination.

Citing the Nov. 15 crash, the Federal Aviation Administration last January called on all airlines to avoid pairing relatively inexperienced crew members in the cockpit.

Waited 27 Minutes

Testimony before board hearings in Denver last March indicated that Flight 1713 was de-iced shortly after leaving the gate but then sat on the ground in subfreezing temperatures and light snow for 27 minutes before being given clearance to take off for Boise, Ida.

Investigators said the delay stemmed from heavy traffic at the airport and confusion in the Stapleton airport control tower as to how several planes were sequenced for takeoff. The board said the crew of Flight 1713 contributed to this confusion by failing to report properly when leaving the gate.

Despite the delay, the NTSB said, Capt. Frank Zvonek, 46, of Carlsbad, Calif., ignored a Continental Airlines policy that requires cockpit crews to taxi back to the pad for a second spraying with an alcohol de-icing solution whenever delays force a plane to wait more than 20 minutes in a snowstorm.

Because of their wing design, early-model DC-9s such as the one involved in the crash are especially vulnerable to takeoff problems resulting from ice. Experts testified that ice no more than .03 of an inch thick could have critically impaired the ability of the plane’s wings to provide adequate lift on takeoff.

Ice Tied to Loss of Control

The board concluded that ice “contamination” on the upper surfaces of the wing led co-pilot Edward Bruecher, 26, of Houston to lose control of the plane as it attempted to take off from Runway 25 Left.

The big plane lifted off, wobbled, pitched to the right and slammed into the ground, scattering debris for more than 1,500 feet along a shallow gully before coming to rest in the freshly fallen snow. Zvonek and Bruecher were among those who died on impact.

The safety board, which issued its report from Washington, expressed concern about the relative inexperience of the cockpit crew, who had never flown together before.

Although Zvonek had more than 12,000 hours of total flight experience, only 33 hours of that time were as the captain of a DC-9. As a relatively inexperienced “high-minimum” pilot, Zvonek was authorized to take off under the limited weather conditions prevailing at the time, but he would not have been allowed to land under those conditions except in case of an emergency.

Experience of Co-Pilot

Bruecher, who had about 3,150 hours of total flight experience in commuter planes and other smaller aircraft before joining Continental in July, 1987, had only 36 hours and 36 minutes of flight time in a DC-9, all of it with Continental.

According to the NTSB, the flight examiner who failed Bruecher in 1985 said the young pilot had “chronic troubles,” became disoriented and “seemed unable to cope with deviations from the routine.” After joining Continental, he had trouble in a jet simulator and “completely lost control” during one simulated flight, according to the line’s training records.

The board did not criticize Continental’s training procedures, although it faulted the airline for not thoroughly checking Bruecher’s previous training records. Continental spokesman Bruce Hicks said that except for the one-time problem in the simulator, Bruecher performed well while training with Continental.