US investigators have opened inquiries into two serious incursion incidents involving Alaska Airlines and Continental Airlines last month. In one incident, an Alaska Boeing 737 departed from the wrong runway at Seattle-Tacoma International airport, while in the other a Continental 757 landed on a taxiway at New York Newark.
The Alaska incident, involving flight AS61 to Juneau, occurred on 30 October when the aircraft was assigned runway 34C for departure. But the twinjet took off from the parallel runway 34R, which is halfway between Seattle-Tacoma's terminal complex and runway 34C. With a length of 3,630m (11,900ft), runway 34R is the longer of the two by about 25%.
"There were no injuries or damage and the flight continued uneventfully to Juneau," says the US National Transportation Safety Board (NTSB). The aircraft was said to be carrying 67 passengers and crew. Local media quote the US Federal Aviation Administration as saying that the crew read back the correct runway assignment to air traffic control.
Meanwhile, the two Continental pilots involved in the Newark taxiway landing incident, on 28 October, have been removed from flight duties. Flight CO1883 had been conducting an approach to runway 29 - on the north side of the airport - after arriving from Orlando, Florida.
According to the FAA's eastern region, the aircraft landed on taxiway Z, which runs along the northern side of, and is parallel to, runway 11/29 - the shortest of Newark's three runways at 2,100m.
The NTSB says the 757 was executing a "circle-to-land" instrument approach at the time.
The aircraft landed at 18:31 on 28 October, half an hour after sunset. None of the 157 passengers and six crew members was injured.
Continental says it is carrying out a review of the landing to discover how the error occurred. "The pilots have been temporarily removed from flying duties and are assisting the company in analysing the incident," it adds.
Continental is also investigating two recent ground-collision incidents involving three of its aircraft. One of its 757s, being towed at Newark, suffered a wing-tip strike last week from a taxiing Lufthansa Boeing 747.
Last month, the starboard winglet of a Continental 737 on pushback clipped the horizontal stabiliser of another Continental 737 at Houston.