B747-400
Flight Crew Air Transport Pilot (ATP)
Troubleshooting; Communication Breakdown
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural MEL / CDL
General Maintenance Action
Procedure; Human Factors; Aircraft; MEL
Aural altitude alert did not function. Autopilot; flight director; MCP; and autothrottles all worked well. I forgot that aural altitude alert is required for RVSM airspace. This was the first revenue flight for this aircraft.  I assumed that this was the normal configuration for this aircraft. We had reviewed differences prior to departure in the QRH so that should have given me heads up that it was not correct.In the future when something is not ordinary; check the DDG (Dispatch Deviations Guide). This would have prompted note to Maintenance and write up of aircraft in this circumstance.
B747 Captain reported that an aircraft was operated in RVSM airspace without a required component.