[SystemSafety] The Accident to SpaceShip2

From: Peter Bernard Ladkin < >
Date: Mon, 3 Aug 2015 14:14:49 +0200


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The NTSB held its public hearing on July 28th. All infos, including presentations from the hearing, available at http://www.ntsb.gov/news/events/Pages/2015_spaceship2_BMG.aspx and the NTSB's provisional executive summary, findings and safety recommendations at http://www.ntsb.gov/news/events/Documents/2015_spaceship2_BMG_abstract.pdf

The NTSB is big on the HazAn not having dealt adequately with HF aspects, including that the accident showed there was a critical system (the feather actuation/stow/lock/mechanism) with a single point of failure, namely human error.

However, I strongly disagree with the "summary" of Alister Macintyre, who wrote about it in the Risks Forum http://catless.ncl.ac.uk/Risks/28.83.html#subj1 He speaks about "cut[ting] corners", and writes as if he thinks various people did things wrong. I don't see much evidence for that at all (although it is possible that some might come with the full report). I see people trying to get a job done, to bring a highly innovative piece of critical engineering - pioneering is an apt word - to fruition. And in this largely novel environment, needing to improve their HazAn. The HazAn is likely substantial intellectual property. Without evidence, it's on the verge of insulting to suggest anyone or any group involved with this project was slacking.

Compare. Lithium-ion primary and auxiliary batteries on the Boeing 787 is also new technology. An FMEA was done that suggested the worst that could happen to the environment during thermal runaway of one or more cells was development of smoke. That FMEA remained unchanged even after a thermal-runaway event during testing burnt down the test facility. And the NTSB visited the fabricating factory where it observed that hazard mitigation, namely certain quality control measures, was not as effective as was thought http://www.ntsb.gov/investigations/AccidentReports/Reports/AIR1401.pdf . Boeing has a lot more at stake - maybe the entire company again, who knows? - in getting it right than the backers of Scaled Composites. And they still didn't get the HazAn right.

When the technology is new, HazAn is a tricky business. No one wants to get it wrong. But they do. And they will. Which is why some of us are working on ways to get it done better.

I say more at http://www.abnormaldistribution.org/2015/08/03/the-accident-to-spaceship-two/

PBL Prof. Peter Bernard Ladkin, Faculty of Technology, University of Bielefeld, 33594 Bielefeld, Germany Je suis Charlie
Tel+msg +49 (0)521 880 7319 www.rvs.uni-bielefeld.de

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systemsafety_at_xxxxxx Received on Mon Aug 03 2015 - 14:15:04 CEST

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