A non GPS equipped A319 displayed a Navigation Display map error which displaced the airport 2.5-3 miles south of the actual location with no alerts; warnings or NAV Accuracy downgrade.

Narrative

[We were flying a] non GPS aircraft. The flight was normal with no failures or cautions. We were in visual conditions with the airport in sight and realized both map displays were not right. The map displays showed the airport runway 2 1/2 - 3 miles south of where the airport really was. The runway localizer was OTS (out of service). Again no warnings or cautions and NAV Accuracy was in HIGH. No required NAVAIDs were listed OTS in the NOTAMs. It appears that the radio updating skewed both FM positions well beyond acceptable tolerances without any warning or NAV accuracy downgrade. This could lead to a dangerous off course condition in a non radar environment. It could also lead to loss of aircraft separation in a radar environment. The new RNAV arrivals do not reference ground based NAVAIDs making it impossible to know if you are on course if the onboard NAV does not recognize that an error is occurring. All though required NAVAIDs are listed on the RNAV approaches; as I look at what NAVAIDs are being accessed by the FMGC during the RNAV approach; it appears that many more are being accessed including localizer DME. Although the runway localizer was OTS the runway DME appeared normal. The cause of these errors must be found. The crew does have the ability to discover this error by observing the IRS drift. If all three IRS have large errors the radio updating should be questioned.