Re: Spacex launch (or lack of it)

Louis Scheffer <lou@xxxxxxxxxxx> wrote:

>"snidely" <Snidely.too@xxxxxxxxx> writes:
>>Derek Lyons wrote:
>>> "Tom Cuddihy" <tom.cuddihy@xxxxxxxxx> wrote:
>
>>> >How do you know what to put on a checklist?
>>> By sitting down before hand an actually thinking and walking through
>>> the launch procedures. Really simple stuff, not rocket surgery.
>>>
>>> >Answer: anything you forgot last time.
>>>
>>> ROTFLMAO.
>
>>Both answers are correct. The draft from before hand will cover
>>90%-98% issues if you've done a decent job, but the real world has a
>>habit of adding at least 1 more reminder than you did.
>
>The checklist problem is harder than it looks. Of course you want the
>checklist to be written by your expert, but it will probably be
>performed by someone else. What looks unambiguous, and impossible
>to get wrong, to the expert may not be clear to the worker (or worse,
>it may be completely clear, but not what the expert intended.)

Wrong. A checklist is a clear set of statements and instructions.
Someone may skip a step, or get them out of order, but it's pretty
hard to make a line like "Shut vent valve LOX-GSE-14" ambiguous.
(Though the Navy tried pretty hard on one particular prodecure to do
so.)

>It's hard for an expert to even envision all the mistakes that a
>user might make, in order to protect against them.

True, but utterly irrelevant. They've done walk throughs, they've
done practice runs... They've had plenty of chances to check the
checklist - this sounds like a single screw up by a single person
compounded by either the failure of the second checker or the failure
to have a second checker.

>And even a run-through wont catch them all, since users are entirely
>capable of making new and innovative mistakes each time.

When they are properly trained then operators (not users) don't make
new and innovative mistakes very often.

>This problem comes up all the time in computer user interfaces.
>You should see the reactions as the UI designer, who is sure their
>instructions are unambiguous, watches through the one-way mirror
>as a user struggles to get through a task.

A completely different and utterly unrelated problem. A checklist
isn't a set of instructions in the normal sense, but a set of
instructions in the 'computer source code' sense.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
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