WASHINGTON — The Delta Air Lines pilots who flew their plane off course over the North Atlantic and came within 30 feet of colliding with another jetliner had made no attempt to verify their location and had no oceanic charts to guide them, investigators said Thursday.
The National Transportation Safety Board said a Canadian investigation into the July 8 incident established just how close the Delta jetliner actually came to colliding with a Continental Airlines jumbo jet after flying 60 miles off course.
Previously, it had been estimated that the two planes had come within about 100 feet of each other 31,000 feet over the North Atlantic. The two planes were carrying nearly 600 people.
The safety board, expressing concern about the failure of the flight crew to verify its flight path across the Atlantic, sent a recommendation to the Federal Aviation Administration to make such verification mandatory.
It said flight crews should be required to use at least two techniques for verifying a plane's computerized route before takeoff and employ at least three other verification techniques during flight.
Current FAA advisories to airlines recommend, but do not require, that flight crews make en route verification of navigational data during cross-oceanic flights where aircraft are not covered by ground-based radar.
In the case of the Delta flight, the board said the crew "did not plot their present or predicted positions upon crossing way points, or perform other (flight) track verification procedures while en route."
"In fact," it said, "the investigation revealed that Delta crew members are not supplied with oceanic charts to graphically display the coordinates and path of the assigned route or track."
Investigators said they believe the Delta Lockheed L-1011 flew off course because a wrong coordinate was punched into the plane's computerized system used for navigation before the plane left London on a flight to Cincinnati.
William Berry, a Delta spokesman, said an airline investigation into the incident found "company procedures were not observed in certain elements of the flight," but he declined to elaborate. Berry said the crew involved in the incident has been disciplined. "They are not flying," he said.