Efficient data storage mechanisms for DAP

Abstract

The cockpit voice recorder (CVR) and digital flight data recorder (DFDR) are the traditional black boxes used in general and commercial aviation aircrafts. These are used to record vital audio and aircraft parameters. Substantial time and monetary expense are incurred after an aircraft accident to retrieve the black boxes and sometimes the recorders are found damaged and unreadable which further inflates aircraft accident investigation time and expenditures. The CVR typically records the voice conversations within the cockpit on 2 (or 4) different channels for a duration of 30 minutes. The DFDR records the aircraft's vital parameters over the entire duration of a flight. The CVR records information in such a way that only the last 30 minutes of voice is available. As a supplement to the existing CVR/DFDR, the authors present the possible transfer of the acquired voice, video and data from the airplane to the ground stations. This transfer is envisioned to be carried out by (a) utilizing the available data link being employed for IP connectivity between the airplane and the ground station to stream live data, voice and video traffic to the appropriate servers on the ground, or (b) storing the data, voice and video streams locally within the airplane and downloading them to the appropriate servers on the ground station. Since numerous aircraft are expected to be in-flight at any given point of time, the management of the downloaded voice and data within the ground stations could easily become a scalability issue. While file transfer mechanisms like FTP provide considerable flexibility in the deployment of DAP, a scalable means of catering to hundreds of airplanes simultaneously would be the adoption of file I/O and block I/O based data transfer mechanisms. Different I/O mechanisms including (a) network file system (NFS), (b) Internet small computer system interface (iSCSI), and (c) enhanced network block device (ENBD) were considered for the current work.