B747 captain reported that an aircraft was operated in rvsm airspace without a required component.

Attributes
ACN	1686795
Time
Date	201909
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Light	Daylight
Aircraft 1
Make Model Name	B747-400
Operating Under FAR Part	Part 121
Flight Phase	Climb
Flight Plan	IFR
Component
Aircraft Component	Integrated Audio System
Person 1
Function	Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural MEL Deviation - Procedural Maintenance Deviation - Procedural Published Material / Policy

Narrative:

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.

Original NASA ASRS Text

Title: B747 Captain reported that an aircraft was operated in RVSM airspace without a required component.

Narrative: 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.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.