Bob CollinsThere’s a little more out today about last month’s near collision between two airplanes departing the airport in Minneapolis. Here’s the initial report from the National Transportation Safety Board.
On September 16, 2010, about 6:49 a.m. CDT, an air traffic control operational error resulted in a near-midair-collision between US Airways flight 1848 (AWE 1848), an Airbus 320, operating as a scheduled 14 Code of Federal Regulations (CFR) part 121 passenger flight en route to Philadelphia, Pennsylvania, carrying five crewmembers and 90 passengers, and Bemidji Aviation Services flight 46 (BMJ46), a Beech 99 cargo flight with only the pilot aboard,operating as a 14 CFR part 135 cargo flight en route ro LaCrosse, Wisconsin. Weather conditions at the time were reported ceiling 900 feet and visibility 10 miles.
Immediately after departure, the tower instructed AWE1848 to turn left heading 260 degrees, which caused the aircraft to cross paths with BMJ on the extended centerline of runway 30L, approximately 1/2 mile past the end of the runway approximately 1,500 feet above the ground. Neither pilot saw the other aircraft because they were operating in instrument meteorological conditions. However, the captain of the US Airways flight reported hearing the Beech 99 pass nearby. Estimates based on recorded radar data indicate that the two aircraft had 50 to 100 feet of vertical separation as they passed each other.
The US Airways aircraft was equipped with a Traffic Alert and Collision Avoidance System (TCAS) that issued climb instructions to the crew to avert collision. The Beech 99 was not equipped with TCAS and the pilot was unaware of the proximity of the Airbus. There were no reports of damage or injuries as a result of the incident.
I wrote extensively about the incident here.
The Star Tribune and Associated Press, however, are characterizing the preliminary report as indicating the cause of the near-miss was a controller issuing an instruction to turn left.
“The reporter is pulling information from our preliminary report,” an NTSB spokesman told me late this morning.
Perhaps the source of the problem was the single instruction to the US Air jet to turn left, but the NTSB report doesn’t exactly say that.
For example, it does not mention the failure of the smaller Bemidji Aviation plane to comply with an instruction to turn left, thus setting it on a potential collision course with the US Air jet who did comply with similar instructions from another controller. And it doesn’t mention the lack of communication between two controllers taking care of different aircraft on different frequencies. Technically, that could be part of an operational error, too.
An NTSB spokeswoman says all the details will be in a report to be issued in several months. That’s called a “probable cause” report. Today’s is a “preliminary report,” which sounds conclusive, but is usually just a restating of facts already in evidence.
