Boeing President outlines proposal and its three layered solution.
Mike Sennett is “on”:
Talking points:
Notes taken as Q/A is live, I typed as fast as I could. Sorry for
any gibberish notes.
- Design Teams and
Context, Data are Items organized for review.
- Commitment to
Safety, FAA and the History of Lessons Learned in place.
- Battery is a backup
function only, generally a ground device and not critical for flight
operations.
- 4 Electrical
generators laid out in sequence with back-ups systems.
- Even with All
generators, auxiliary power failures, a ram air backs up all
emergency level power.
- Redundant and
systems exist for all airplane big event failures.
A battery fire is critical of airplane in flight to the extent
environmental and structural risks.
Lithium Ion Battery
- Matured and
solid technology as of today.
- Many benefits
for Lithium -Ion out performs other battery types.
- Provides
Significant ground power
- Lightweight
- Long lasting
System Design
- Testing requires
Solution offered, and Does not fail in tests
- Back-up system
in the event of failure is covered by four layers of systems
- Interactive
management from pilot and back to electronics bay.
- Redundancy in
computers and displays for both Pilot and Co-pilot
- Co-pilot is
redundant to pilot with his own set of equipment.
- No single
failure would ever endanger a flight.
Japan and Boston Event
What happened, small flames in Boston, 3" size, lots of gases and on the other incident no fire just heat and venting.
Battery ventilated the cell to prevent overheating. Other cells
vented is a protection mechanism as an electrolytic "smoke", not a
fire spread just heat. Battery failed and airplane responded as predicted and
as expected under an event. It protected the heat from electrolyte venting
sending gases overboard. Damage limited to battery not to the airplane.
Thermal Runaway
A vague euphemistic term for battery overload and shorting
event accelerating the rise in heat leading to possibility of
fire, if elements are present such as oxygen or fuel in combination of heat.
Venting is a result of a thermal runaway event. Too much heat puts
airplane at risk, the two separate events were not do to overcharging,
which is the number one fear endangering the Boeing aircraft from the
electronics bay. These two events did not have an overcharging problem. Boeing
has not yet experienced an overcharging in the 787 ever! The 787 did not
overcharge, a worst fear for this battery where it didn't happened, but systems
handled the heat event.
Experts needed to increase layers of protection. Top 500 engineers
added just for this problem, both inside and outside the company are teaming up
over the last months for resolving what happened..
From:
- Auto
manufacturing
- Electrical
Engineering Labs
- University
institutional testing
Gained assurance from outside resources to help resolve problem
200,000 hours expended from all sources for the resolution and mitigation plan.
This is a representation of a process which to understand the
battery problem. Hundreds of engineers are focused one mission where they look
at ways of stabilizing the battery making risk assessments for all
possible condition which can cause a Thermal Run Away.
Changes were made controlling higher and lower operating limits of
the charger flow to the battery.
Battery changes in general:
- Venting
preventing, isolating cells preventing the spreading of damage
- Cell change
- Case Change
- Wire Bundling
- Dielectric
protection to stop venting and propagating heating to other cells nested
in the enclosure.
- Charging circuitry wave
link is gentler from charger.
Encasement prevents spread of fire, a number one risk.
Enclosure prevents ever having a fire in the first place and vents
into enclosure sending gases overboard in a dedicated vent line.
A battery destruction does not endanger aircraft. The risk comes
from spreading heat, and fire in the electronic bay from the battery. If smoke,
fire, and heat are contained in the enclosure, the aircraft is not endangered
during flight or landing on the ground.
Significant testing on enclosure is very good so far and is
positive report after six weeks of testing.
Starvation of fire elements does not require and extinguisher
system, contained heat and pressure is prevented from building up. After six
weeks of testing on new design they have three layers of protection for the
battery.
Three Layers
- Event prevention
- Propagation
- Plane
protection.
Prioritizing fixes after approval:
- Fleet
installation of flying customers,
- And then
production aircraft.
Safety is important to the Comprehensive set of solutions for the
battery.
787 is extremely safe airplane. Sennett puts his life on
the 787 with his family
He demonstrates on a central chart on a fault tree, both likely or
unlikely events, 80 potential things that could wrong placed into four
categories. Investigative team comes from the field and works back inward from
the event to the lab. the other team works from the lab out to the event taking
a different perspective.
Two teams, one from assumptions and theories and other team field
investigators following actual conditions, parts and performing systems, center
on solution.
Conner back on the podium, Q&A
Test Flights & Venting When? Answer: Small amount air or
venting releases electrolytic no oxygen no fire. Release reduces
heat and no fire. More oxygen had only a small millisecond
fires, instantaneously out.
Flights: Single flight to test battery in air.
Laboratory is extensive on the ground will be done in weeks
Commercial Back to Flight? Apology made.
Commercial Airplane will be in the air in more than just weeks. Root
cause appropriate correction to parts not known is an unknown root cause is
factored over by robust improvement which will not allow this to occur. Try our
best against a failure, enclosure allows airplane time to land. Giving Safe
flight and landing having the enclosure.
Q: Change from enclosure and system eliminates no risk of fire?
A: Yes no chance of fire!
Confident in battery future with no battery failure. It it ever
does, the plane will fly and then land safely. Thousands of fire event with
battery failures have happened, with no loss with conventional batteries used
in flights today.
End of note taking:
No comments:
Post a Comment