The CVR will be found - it is a matter of search organization, the will of all parties and patience. The search area is relatively small so it is a matter of when not if.
The CVR's importance to the investigation and to consequences for all parties cannot be overstated. So funding such a search will not be an issue.
AF447's wreckage & both recorders were found after two years of searching under ~3000m of water and after some repair work both yielded their data. The higher forward speed here presents different 'trajectories" of the parts than AF447 but we assume that these are search experts and that there is lots of oversight.
They're not even at the 30-day mark yet.
Since it hasn't been mentioned yet with regarding to sensors, computer voting-systems trying to mimic "decidability", redundancies in mission-critical / single-point-of-failure systems and the impossibility of getting it right 100% of the time with only 3 sensors, (Perpignan), two documents from Leslie Lamport and one from Kevin Driscoll are worth the time and effort:
Reaching Agreement in the Presence of Faults - Leslie Lamport
The Byzantine Generals Problem - Leslie Lamport
Byzantine Fault Tolerance, from Theory to Reality - Kevin Driscoll
From
Driscoll:
What You Thought Could Never Happen
In English, the phrase “one in a million” is popularly used to describe the highly improbable. The ratio itself is difficult to comprehend. The easiest way to give it reason is to equate it to real-world expectations. For example, the probability of winning the U.K. National Lottery is around one in fourteen million; the probability of getting struck by lightning in the U.S. is around one in six hundred thousand [1]. It is not safe to rely on intuition for reasoning about unfathomably small probabilities (for example, the 1-in-1,000,000,000 maximum failure probability for critical aerospace systems, (usually expressed as 10-9 hrs).
It is problematic in two ways: (1) real-world parallels are beyond typical human experience and comprehension; (2) faults that are not recognized, such as Byzantine faults, are incorrectly assumed to occur with zero or very low probability. The lack of recognition causes additional issues in that it allows the manifestation of such faults to pass unnoticed or be otherwise misclassified, reinforcing the misconception of low probability of occurrence.
The lack of recognition leads to repeating the “Legionnaire’s Disease” phenomenon. After its “discovery” in 1976, a search of medical records found that the disease had seldom occurred for many decades. The lack of shared knowledge and the disease’s rarity made each occurrence appear to be unique. Only after 1976 was it realized that all these “unique” occurrences had a common cause. Similarly, an observation of a Byzantine failure will not be recognized as being an instance of a known class of failure by those who are not intimately familiar with Byzantine failures. The intent of this paper is to redress this situation. Drawing from the authors’ experiences with Byzantine failures in real-world systems, this paper shows that Byzantine problems are real, have nasty properties, and are likely to increase in frequency with emerging technology trends. Some of the myths with respect to the containment of Byzantine faults are dispelled and suitable mitigation strategies and architectures are discussed.