ering flight, the pilots probably could not understand what was
happening, and ended into catastophic result.
CAL A300 crashed just before landing at Nagoya Airport on April 26,
1994, killed 264 crew and passengers. This was the second-worst airline disaster in
Japanese history, following the above mentioned JAL crash. After more than two years of
investigation, Aircraft Accident Investigation Commission issued the report, and it says
that the accident was caused by multiple errors by the cockpit crew in controlling the
computer-operated aircraft. According to the report, the copilot mistakenly operated the
go-around lever, while the plane was landing manually. So the airplane gained speed and
altitude, but deviating from its approach course.
The captain cautioned the copilot that he had moved go-around lever and
instructed him to disengage that mode, but he could not change it. There was a desperate
conflict between man and machine. The computer rejected the crew's attempt to go to a
lower altitude because it was automatically trying to force the plane to gain altitude.
The captain gave up landing in that condition and engaged the go-around mode again. But
this led to a sharp increase in pitch angle, and the engines stalled, leading to the
crash.
According to the report, lack of understading of the operating systems
among the crew resulted to the crash. It also points out that there was no warning or
recognition function to clearly alert the crew to the abnormal out-of-trim condition.
5. Troubles of sophisticated systems
In both cases, we can suppose that the pilots could not understand the
reason why they could not control their planes. The point of sameness is the fact that
they do not "see" the cause of troubles. Whatever so many informations are
displayed, some is only a noise: unwanted signal, some is difficult to "read".
Special features arisen from high-technology products are, "can't see",
"can't recognize", and "can't find the solution in a moment" in
common.
It is true that large percent of sea and air accidents have reportedly
been caused by human errors. But it is unjust for us to leave these complicate accidents
to simple human errors. It must be noticed that human error, or mistake, could be
introduced in many stages, such as design of a system, construction, maintenance,
operation and even in management phase.
There is an accident, called linear accident, whose relation between
cause and effect is simple and corresponds one to one. Another is called complex accident
and it has multiple causes from various phases. In advanced system, many parts and
functions are mutually related, and blackboxed in many places. So we can not find out what
is happening and where the damage is by intuition.
As a system is being designed, many possibility of occurances are taken
into account to avoid an accident. But many apparatus and systems are almost blackboxes to
a driver or an operator as technology progress. Unless the operator knows almost all
systems, it is impossible for him to handle correctly.
One of other features is: no idle space. Every systems are connected
very
