It’s been one week since American Eagle Flight 5342 crashed into the Potomac River, and the work has only begun to recover from the deadliest U.S.

In updates throughout the weekend, the NTSB detailed that as of February 8, it had recovered all of the major pieces of the PSA Airlines Mitsubishi CRJ700 and the United States Army (USA) Sikorsky UH-60 Black Hawk helicopter. The parts were moved to a secure airport facility for further examination and documentation, the NTSB added.

Investigators trying to determine what caused last week’s deadly midair collision between a US military Black Hawk helicopter and an American Airlines plane near Washington, DC, briefed lawmakers Thursday on what they’ve learned after combing through data from both aircraft and air traffic control.