Why have PMDG not implemented the NG's auto tuning capability for VOR 1 and 2? The introduction manual says this is not available in in the aircraft its message from the beta testers. The real aircraft is certainly capable of autotuning a VOR from the FMS. There is no auto/manual switch on the VHF NAV control head, unlike the 737 Classic, but in the NG this is handled automatically. The FMC NAV STATUS page shows an M by the frequency to indicate manual tuning, but with a route activated this never changes to an A to show auto-tuning. In the supplied FCOM the NAV STATUS page example shows an A to indicate a VOR tuned automatically by the FMS. The manual does mention a sim help feature to auto tune what it refers to as OBS (I assume it means VOR), but I have not found this option yet. Kevin Hall

Based on my memory after reading the manual, there is NO autotuning feature for FMS (unlike PMDG 747 and LDS 767). Even if such is actually present in the real aircraft (as you say so)... Therefore in the NGX, you have to actually tune the frequencies manually. Such limitations in these aircraft I can accept as in every plane, there are pros and cons.

The auto tune is part of the DME-DME portion of the nav system that most aircraft have. The FMS will use GPS as the first solution. This will also allow the FMS to monitor INS error. Some system will tighten up the INS. The next solution is DME-DME. If GPS sys fails or the signal is lost, the FMS will cross tune the nearest VORs to keep up with the location of the aircraft. The last solution is pure INS. The FMS will progress through these nav solutions based on whats available. Most modern high tech nav systems use this process.

The auto tune is part of the DME-DME portion of the nav system that most aircraft have. The FMS will use GPS as the first solution. This will also allow the FMS to monitor INS error. Some system will tighten up the INS. The next solution is DME-DME. If GPS sys fails or the signal is lost, the FMS will cross tune the nearest VORs to keep up with the location of the aircraft. The last solution is pure INS. The FMS will progress through these nav solutions based on whats available. Most modern high tech nav systems use this process.

Thanks for the info.

If you look at the supplied FCOM Vol 2, page 11.42.52 and 11.42.53 you'll see what I mean. Note it shows SEA VOR tuning mode as A (autotuned). In the NGX the display always shows M. DME auto tune is modelled in the NGX but VOR autotune is not, Page 11.42.54 explicitly states that the VOR tuning mode can be either M (Manual), P (Procedural) or A (Automatic). VOR auto tuning is alse referred to at http://www.b737.org....on.htm#Position ) . This is for all 737 models, but the NG is specifically mentioned.

Radio Position: This is computed automatically by the FMC. Best results are achieved with both Nav boxes selected to AUTO (happens automatically on NG), thus allowing the FMC to select the optimum DME or VOR stations required for the position fix. Series 500 aircraft have an extra dedicated DME interogator (hidden) for this purpose and NG's have two. Radio position is found from either a pair of DME stations that have the best range and geometry or from DME/VOR or even DME/LOC

Without the ability to tune a VOR, the FMS would be reliant on DME-DME for position updating. Kevin Hall

Well, Could PMDG team add this option in equipments settings? Why not? I would like to see my 737ngx with auto tuning capability for VOR 1 and 2!