Aviation Accident Summaries

Aviation Accident Summary ANC00IA088

ANCHORAGE, AK, USA

Aircraft #1

N935AS

McDonnell Douglas MD-82

Analysis

The crew of a McDonnell Douglas MD-82 airplane reported a near midair collision, about 15 miles north of the airplane's destination airport, while operating in Class E airspace. The captain of the MD-82 said that during the initial part of the approach, while descending through 4,000 feet msl, instrument meteorological conditions (IMC) prevailed. He added that approach control then cleared him to descend to 3,000 feet msl, on a heading of 160 degrees, and reported that there was traffic about 1 mile to the southwest, with an indicated altitude of 2,500 feet msl. As he started to level the airplane at 3,000 feet msl, and as the airplane descended below the clouds, he immediately saw a twin-engine airplane climbing from 2,500 feet toward his airplane. He said that he had very little time to react before the twin-engine airplane passed to the left and below of his airplane, about 500 feet horizontally, and 200 feet vertically. The captain added that his airplane's traffic alert and collision avoidance system (TCAS) was inoperative at the time of the incident. Subsequently, no collision avoidance alert was provided to the crew of the MD-82. A review of approach control records revealed that the twin engine Piper Seneca was not in contact with approach control, nor was it required to be, while operating within Class E airspace. A review of air-ground radio communications tapes revealed that the controller advised the MD-82 pilot that there was conflicting traffic, about one mile southwest of his location, headed in a northwesterly direction, and that the altitude was indicating 2,500 feet. About 20 seconds later the pilot of the MD-82 reported to the controller, in part: "...ha, that was pretty close on that traffic."

Factual Information

On July 11, 2000, about 1138 Alaska daylight time, the crew of N935AS, a McDonnell Douglas MD-82 airplane, reported a near midair collision, about 15 miles north of the Ted Stevens International Airport, Anchorage, Alaska. The flight was being conducted under Title 14, CFR Part 121, as a scheduled domestic passenger flight, operated by Alaska Airlines as Flight 131. There were no injuries to the two pilots, three flight attendants, or the 102 passengers aboard. Visual meteorological conditions prevailed at the Ted Stevens International Airport, and an instrument flight plan had been filed. The flight originated about 0900 Pacific daylight time from the Seattle-Tacoma International Airport, Seattle, Washington. During a telephone conversation with the National Transportation Safety Board investigator-in-charge on July 17, the captain of the MD-82 stated that during approach to the Ted Stevens International Airport, approach control was providing radar vectors in order to intercept the localizer for runway 14. He said that during the initial part of the approach, while descending through 4,000 feet msl, instrument meteorological conditions (IMC) prevailed. The captain stated that approach control cleared him to descend to 3,000 feet msl, on a heading of 160 degrees, and reported that there was traffic about 1 mile to the southwest, with an indicated altitude of 2,500 feet msl. The captain said that as he started to level the airplane at 3,000 feet msl, and as the airplane descended below the clouds, he immediately saw a twin-engine airplane climbing from 2,500 feet toward his airplane. He said that he had very little time to react before the twin-engine airplane passed to the left and below of his airplane, about 500 feet horizontally, and 200 feet vertically. At the time of the incident both airplanes were operating in Class E airspace. The captain added that his airplane's traffic alert and collision avoidance system (TCAS) was inoperative at the time of the incident. Subsequently, no collision avoidance alert was provided to the crew of the MD-82. A review of approach control records revealed that the twin engine Piper Seneca, N39522, was not in contact with approach control, nor was it required to be. During a telephone conversation with the National Transportation Safety Board investigator-in-charge on July 14, the designated FAA pilot examiner aboard the second airplane involved in the near midair collision incident, reported that he was conducting a multi-engine check ride at the time of the incident. He said that cloud conditions in the area were scattered, with higher clouds to the north of his location. He added that he was able to use a large open area that was clear of clouds. He said that just after completing one of the required maneuvers, about 3,000 msl, and about one-half mile away from the cloud bank, an Alaska Airline MD-82 suddenly appeared from out of the clouds on the right side of his airplane. He added that the MD-82 was about 800 feet above his airplane as it passed from the right to the left. A review of air-ground radio communications tapes maintained by the FAA at the Anchorage TRACON revealed that the controller advised the MD-82 pilot that there was conflicting traffic, about one mile southwest of his location, headed in a northwesterly direction, and that the altitude was indicating 2,500 feet. About 20 seconds later the pilot of the MD-82 reported to the controller, in part: "...ha, that was pretty close on that traffic."

Probable Cause and Findings

An inoperative traffic alert and collision avoidance system (TCAS).

 

Source: NTSB Aviation Accident Database

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