The 30 minute solid-state Cockpit Voice Recorder (CVR) captured a portion of the flight that is being analyzed.
Looks like some of the solid-state CVR's record 30 minutes, some do two hours. Maybe this one only did 30 minutes.
From the preamble of the BUF crash CVR transcript:
Recorder Description
Per Federal regulation, CVRs record a minimum of the last 30 minutes of aircraft operation; this is accomplished by recording over the oldest audio data. When the CVR is deactivated or removed from the airplane, it retains only the most recent 30 minutes or 2 hours of CVR operation, depending on the CVR model. This model CVR, the Honeywell 6022 SSCVR 120, is a solid-state CVR that records 2 hours of digital cockpit audio. The recorded audio data is separated by the Honeywell download software into 2 sets of audio data files: a) a 2-channel recording containing the last 2 hours of recorded events and b) a 4-channel recording containing the last 30 minutes of recorded events. During the 2-hour portion of the recording, one channel contains audio information from the cockpit area microphone (CAM) and the other channel contains a mixture of two audio sources: the captain’s audio panel information and the first officer’s audio panel information. The 30-minute portion of the recording contains 4 channels of audio data; one channel for each flight crew, one channel for the CAM audio information, and a fourth channel available for interphone, public address, or flight deck jumpseat audio information.
http://www.ntsb.gov/Dockets/Aviation...027/418693.pdf