[SystemSafety] "FAA chief '100% confident' of 737 MAX safety as flights to resume"

[Michael Holloway]

Bev,

Thank you for your thoughtful reply. I wonder whether our differing
perceptions of what a typical speaker of our country's version of English
would mean by "100% certain" reflects an actual difference, or a mistake in
my or your (or perhaps both of our) perceptions. Perhaps I shall conduct an
informal inquiry among my friends from both countries. Perhaps I should
have done that before making my original post. :-)

I agree that the substantive issue is how safe the tweaked Max is likely to
be, and not the words spoken (but this thread seems to me to  have been
more about the latter).  I also agree, to the extent that I have sufficient
knowledge to have an opinion worth being considered (which is not much),
that the physical design of the Max is flawed. I also share your disbelief
that any honest and competent engineer would attribute *certainty* to his
or her belief in the efficacy of the software solution for ensuring
sufficient safety.

Nevertheless, based on what I personally know about what has been done
since the grounding, I have no reason to believe that there exists any
credible reason to avoid getting on a 737 MAX flight in favor of a flight
on a different airplane, assuming all other factors are the same. Because
of my contacts, the extent of my personal knowledge on this subject is
likely deeper than that of many people on this list. It is also certainly
shallower than that of some.


*--cMh*

mercy > judgment
love > faith & hope
grace > law



On Fri, Nov 20, 2020 at 10:29 AM Littlewood, Bev <
Bev.Littlewood.1 at city.ac.uk> wrote:

> Michael
>
> I don’t know about US speakers of our (apparently) common language. But I
> think English English speakers - and readers - would regard “100%
> confident” to mean “certain”. It does not seem to me to be a
> “quantification of confidence”, as you put it, but a declaration of absence
> of doubt.
>
> The substantive issue seems to me to be not what this man said, but rather
> how safe *is* the tweaked Max. Tom Ferrell puts the technical issues
> well, and Olwen’s characterisation of the problem is admirably and wittily
> succinct:
>
> If I want computer-moderated aerodynamic instability, I'll fly in an
> Su-35. What the 737 MAX needs isn't revamped systems but a new airframe
> design.
>
> I find it hard to believe that any honest and competent engineer could
> tell the public that he was *certain* a software solution to the problem
> of such a flawed design was sufficiently safe. What do you think, Michael?
> I know you don’t like numbers, but tell us, qualitatively at least, how
> safe you think it is likely to be.
>
> All the best
>
> Bev
>
>
>
> On 20 Nov 2020, at 14:41, Michael Holloway <cmh at alumni.virginia.edu>
> wrote:
>
> Only have the energy and interest to reply to one bit of PBL's response ...
>
> > So you are suggesting that he is at least as confident that he won't
> die, flying in a MAX, as he is
> > that 2+2=4 ? Or should that confidence be relativised somehow?
>
> I am saying that to the best of my knowledge, the most common intended
> meaning of the phrase "100% confident" when used by a typical speaker in
> the US is much closer to, "confident enough to stake my reputation and
> life  on it," than it is to "certain beyond any and all doubt," or even to
> "certain beyond a reasonable doubt." Personally, I abhor the use of any
> phrase that appears to quantify confidence, but I see no benefit, and some
> harm, in harping on such a usage, when the meaning is as generally well
> understood as it is here.
>
>
> *-- Michael*
>
> mercy > judgment
> love > faith & hope
> grace > law
>
>
>
> On Fri, Nov 20, 2020 at 8:44 AM Peter Bernard Ladkin <ladkin at causalis.com>
> wrote:
>
>> On 2020-11-20 14:26 , Michael Holloway wrote:
>> >  the criticism here is ridiculous.
>>
>> Thanks, Mike. Might you have a technical, rather than an emotional,
>> reaction to share?
>>
>> > First, it is pedantry of an extreme sort to think that "100% confident"
>> means anything more
>> > than "as
>> > confident as it is possible for me to be."
>>
>> So you are suggesting that he is at least as confident that he won't die,
>> flying in a MAX, as he is
>> that 2+2=4 ? Or should that confidence be relativised somehow?
>>
>> > Third, everything Tom wrote about the level of scrutiny the plane has
>> undergone is correct.
>>
>> Yes. And that the defined procedures are not enough has been pointed out
>> twice in reports.
>>
>> After Ermenonville, the DC-10 became "the most scrutinized [sic] aircraft
>> in the history of the
>> commercial transport fleet." Then came Sioux City. Along with nobody
>> noticing that you could lose
>> structural integrity if you lost pressure in one half of the PV (which
>> led to Ermenonville through a
>> couple of other occurrences), nobody apparently noticed that they had
>> routed all the control system
>> hydraulics through one spot in the tail, which was duly sliced through by
>> a shed blade. Many put
>> that down to the overall design process of the airplane and worried about
>> other oversights. Which
>> ended up being, some say, why the DC-10 fleet converted to freighters,
>> followed quite quickly by the
>> MD-11.
>>
>> PBL
>>
>> Prof. Peter Bernard Ladkin, Bielefeld, Germany
>> ClaireTheWhiteRabbit RIP
>> Tel+msg +49 (0)521 880 7319  www.rvs-bi.de
>>
>>
>>
>>
>>
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