iscrepancy: 6.4 Squawk from flight test - On RNAV approach VNAV worked and then became unavailable on approach Ref. SC 13175 6.12 Also crew states Predictive Raim fail Resolution: Removed defective #2 VHF Nay Receiver P/N 622-7194-201, S/N 3647 to be sent out for repair. Installed modified #2 VHF Nav Receiver