DALLAS (CBSDFW.COM/AP) — Federal investigators have issued a preliminary report on the plane crash at Addison Airport last month that killed all 10 people on board.

The National Transportation Safety Board has been investigating the crash since it happened on June 30 and killed eight passengers, the pilot and the co-pilot.

The NTSB’s report issued this week offered no new insights into what caused the crash of the twin-engine Beechcraft BE-350 King Air. Investigators have been listening to voice recordings from the plane’s cockpit, looking into videos of the crash and talking to witnesses.

NTSB images captured by drone at accident site in Addison, Texas where a Beech BE-350 crashed into a hangar on June 30, 2019 at Addison Airport. (credit: NTSB)

The voice recording captured a crew member’s comment that there seemed to be a problem with the left engine. The report says technical experts will be convened to further review the recording.

“Crew comment consistent with confusion occurred about 12 seconds before the end of the recording. Crew comment regarding a problem with the left engine occurred about eight seconds before the end of the recording. Three automated bank angle oral alerts began about three seconds before the end of the recording,” the NTSB said at a news conference two days after the crash.

Damage to an airplane hangar after a plane crash killed 10 people at the Addison Municipal Airport. (credit: Chopper 11)

The report quotes one witness as saying the aircraft’s engines sounded quieter than usual and seemed to lack sufficient power for takeoff when it lifted off the runway. Witnesses said the plane banked left before crashing into a hangar.

(© Copyright 2019 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)