B-747-400 Cockpit Voice Recorder

[Flyin' South]

Does anyone know the type of CVR installed in the B-747-400 and/or the amount of time it will record before overwriting itself?

I know that older model CVRs overwrite the tape after 30 min., but newer solid state digital units can go for 2 hours before overwriting the recording. Does the -400 have the 2 hour models?

Anyone know of any links to -400 CVR specs?

Thanks.

 

[mainah]

Quote from the Boeing 747-400 Systems Guide- "A multiple-channel voice recorder with cockpit area microphone is installed. It records the last thirty minutes of flight crew communications and is automatically erased so that only the last thirty minutes remains recorded."