Recorded conversations by pilots on a cargo jet carrying packages for Amazon.com Inc. that crashed last month near Houston reveal they began losing control of the aircraft about 18 seconds before it slammed into a shallow bay, investigators said Tuesday.

The communications captured on the cockpit sound recorder were "consistent with a loss of control of the aircraft," according to a press release issued by the National Transportation Safety Board. The NTSB recovered the crash-proof cockpit recorder and another black box storing flight data in recent days and brought them to its lab in Washington for analysis.

The press release, offering a first glimpse of what happened on the Boeing Co. 767-300 as it was preparing to land at Houston's George Bush Intercontinental Airport Feb. 23, still doesn't explain its mysterious, abrupt dive. The second recorder contained detailed data from the accident flight as well as 16 previous ones, but none of its contents was revealed in the NTSB statement.