From all the articles written gains an understanding of a paradox
on the electrical systems fault of battery vs electrical current. What has been
discovered is:
· Some
voltage irregularities in its battery charging.
· Internal
electrical shorts occurring in its battery
· An
understated fire protection, and exposure of gaseous discharges, compromising
hull atmosphere existed.
· Lack of
diligence for its battery production and testing.
· No known
causal listing of how a battery fails under operational tasks.
At this point Boeing can only break down the system in a series of
controls that isolate probable causes for a failure. Establish a safety
protocol for an unknown cause, but towards eliminating known risks within the
electrical system and Lithium-Ion Battery performance.
So, without knowing causal steps towards for: run away instability,
fire, and overheating, Boeing remains stumped on quantifying a solution
specifically for the Lithium-Ion battery’s melt down. All those flights
and cycles made without an incidence, then bam, two hot batteries within a
short space of time.
Boeing has to review the age of the affected system, cycles and
parts through its parts batch numbers. Any anomaly from parts production on
those aircraft can trace back to origin. They are now past that phase of the
investigation. Then they looked at the charging unit and any factors that
contribute to the Lithium-Ion battery health, as its charging unit inputs or
discharges through voltage regulation.
Boeing determined an occasional spike from the charging unit,
could contribute to degradation of the battery health by creating the
possibility of electrical shorts or fault at battery cell level. This could
continue to strain the battery as more shorts continue to occur, and the demand
increases on the healthy cell area of the battery.
The operational range of the battery is compromised with these
“shorts”, and leads to an overheating battery, discharging heated gases and
finally fire. No one can absolutely confirm this type of battery failure
with these progressions, while under its operational load. Boeing now has
monitoring of a battery’s thermal load and efficiency skewed towards thermal
values which would indicate a degrading battery function is occurring from
shorts. The front line of Boeing’s robust solution is at the factory level of:
· Checking
it twice before leaving the factory floor.
· Voltage
range regulation having tighter low and top range numbers where no anomaly can
pass affecting cell integrity from shorts and a depletion of its cellular
performance, which would cause a heat, gas fire condition.
· Securing
the battery from heat propagation from cell to cell under failing conditions.
· Denying
fire its oxygen.
· Containing
the battery in a sealed stainless steel fire proof enclosure.
· Venting
deadly gases over board.
The first two bullets are for chasing unknown rainbows of cause,
and taking on these measures could be the simple solution. By not ever having a
fire/heat/gas problem again, would suggest somewhere in there was the problem
and the solution.
If Boeing never has another fire in that area over the next
million or so hours, then they guessed correctly with solid assumptions. If “they”
somehow, missed the mark on those two bullet point, then they have a robust
safety containment system that will get everyone home safely.
Boeing has given the FAA, NTSB and others this assurance, techno
paper, and its best effort for a resolution. The FAA will test the
assumptions and logic as a valid substitute in place knowing causal
factors. The containment and safety systems makes root cause a moot
point.
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