Re: [SystemSafety] The Accident to SpaceShip2

From: Matthew Squair < >
Date: Tue, 4 Aug 2015 20:20:22 +1000


I agree, hazard identification is the <<most>> difficult and <<most>> neglected, at least in my opinion, part of safety engineering.

We should not neglect the power of such accidents to inform a safety program. The Americans would have in all likelihood lost Apollo 11 or another mission had it not been for the design changes introduced in the aftermath of the Apollo 1 fire. Ditto for the Thresher disaster.

Matthew Squair

MIEAust, CPEng
Mob: +61 488770655
Email; Mattsquair_at_xxxxxx
Web: http://criticaluncertainties.com

On 3 Aug 2015, at 10:14 pm, Peter Bernard Ladkin < ladkin_at_xxxxxx

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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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