In modern flying, do we need pilots to be able to accurately track an NDB with raw data? If you have lost most of your Nav systems in a modern aircraft AND have to land only via a raw data NDB procedure - displayed on the tiny back-up instrument(s) - it is a very very bad day - normally systems can be reset, or there will be at least a VOR or a Cat l ILS approach or radar vectors available, or within easy reach.
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I agree.
In my experience of modern highly redundant aircraft systems, you can pile on the faults and the overall experience slowly degrades but is essentially not that much different to normal, until the last failure when everything goes blank. Given that “raw data” on EFIS goes through a lot of processing before being synthetically presented, problems that are significant enough to cause serious navigational issues will likely leave you with little to go on as MMRs have combined a lot of independent units into one. On the aircraft I fly at the moment, you need a CDU to tune navaids manually, so if it becomes unavailable, that’s it...