There are a few different notions of risk used in dependability engineering. One notion, used in finance and in engineering safety, is from De Moivre (1712, De Mensura Sortis in the Proceedings of the Royal Society) and is (A) the expected value of loss (people in engineering say “combination of severity and likelihood”). A second…
Alister Macintyre noted in the Risks Forum 28.83 that the US National Transportation Safety Board (NTSB) released results of their investigation into the October 31, 2014 crash of SpaceShipTwo near Mojave, California. The NTSB has released a preliminary summary, findings and safety recommendations for the purpose of holding the public hearing on July 28, 2015.…
……. but not the one you thought! Jim Reisert reported in Risks 28.66 ( Volvo horrible self-parking car accident) on a story in fusion.net on 2015-05-26 about a video of an accident with a Volvo car, apparently performing a demo in the Dominican Republic. The fusion.net story is by Kashmir Hill. Hill says “….[the video]…
The US Government Accounting Office has published a report into the US Federal Aviation Administration’s possible vulnerabilities to cyberattack. One of my respected colleagues, John Knight, was interviewed for it. (While I’m at it, let me recommend highly John’s inexpensive textbook Fundamentals of Dependable Computing for Software Engineers. It has been very well thought through…
It is astonishing, maybe unique, about the Germanwings Flight 4U 9525 event how quickly it seems to have been explanatorily resolved. Egyptair Flight 990 (1999) took the “usual time” with the NTSB until it was resolved, and at the end certain participants in the investigation were still maintaining that technical problems with elevator/stabiliser had not…
19:15 CEST on Friday 3rd April The BEA have recovered the Flight Data Recorder and read it. They issued a communiqué. Here is my translation of the pertinent paragraph: At a first reading it appears that the pilot in the cockpit used the autopilot to command a descent to an altitude of 100 ft, then,…
OK, the discussion on these basic concepts continues (see the threads “Paper on Software Reliability and the Urn Model”, “Practical Statistical Evaluation of Critical Software”, and “Fault, Failure and Reliability Again (short)” in the System Safety List archive. This is a lengthy-ish note with a simple point: the notions of software failure, software fault, and…