Wichita ? The pilot of a small plane that crashed into a flight training building at a Wichita airport last week declared an emergency about a minute after taking off, saying he had “lost the left engine,” the National Transportation Safety Board said Thursday.

The NTSB’s preliminary report said witnesses on the ground estimated the plane was fewer than 150 feet above land when it began a left turn. Witnesses reported the plane had its landing gear down before it hit the Flight Safety International building at Wichita Mid-Continent Airport. The pilot and three people in the building died. Six others were injured, two of them seriously.

The left wing separated after hitting the building just below the roof line. The nose struck the roof and the plane slid for about 20 to 30 feet before the tail section came over the top, followed by a large explosion.

The NTSB said it had obtained surveillance video from surroundings buildings along with a cockpit voice recorder. The plane was also equipped with flight data units.

Authorities had previously identified the pilot as Mark Goldstein, 53, of Wichita. Goldstein was an experienced pilot who had logged 3,000 hours of flight time as of Aug. 4, the NTSB said. He had worked as an air traffic controller for 24 years in Wichita before retiring earlier this year. Goldstein was working as a contract pilot and was taking the aircraft to Mena, Arkansas, for painting and interior refurbishing work.

The twin-engine King Air was registered and operated by Gilleland Aviation in Georgetown, Texas, according to the report. The pilot filed an instrument flight plan before taking off at 9:47 a.m. CDT on Oct. 30 for the flight to Mena Intermountain Municipal Airport. At 9:48 a.m., Goldstein declared an air emergency and stated he had lost the left engine.

One witness told NTSB investigators he heard a reduction in power on one engine before the plane entered the turn. Another said the plane was in a left turn as it approached hangars east of the facility, then the wings leveled as it flew west toward the building. The landing gear was down and locked, the flaps extended, and the right engine was at full power.

Another witness said the plane was in a descending left turn before hitting the northeast corner of the building. He said both propellers were rotating, but he could not determine at what power setting. The left engine struck the building first, followed by a section of the left wing, the report said.