NTSB Testimony to the US Senate on safety, 787; FAA reviewing ETOPS

The Chair of the National Transportation Safety Board testified today before the US Senate. The 11-page testimony is here.

Sen. Jay Rockefeller of the Commerce Committee had this to say. This news article contains this:

The testimony, however, comes amid growing frustration and concern expressed by some senior Boeing officials about what they contend is the FAA’s drawn-out decision-making process. Procedures for conducting ground and airborne tests of the redesigned batteries–as well as detailed criteria for determining their success–were agreed on by Boeing and the FAA before testing started.

We believe the FAA won’t approve anything until after the NTSB hearing April 23-24 on the Japan Air Lines incident, not based on anything we know but simply an assessment of the politics involved.

Testimony by FAA Administrator Michael Huerta has not as yet been posted on the FAA website.

Flight Global reports that the FAA testimony revealed the agency is reviewing the 787’s ETOPS, confirming a story Reuters had last month (and which Boeing dismissed as speculation).

Reuters has this story today on Huerta’s comments. It sounds like he meant to say 180 minutes will be OK, but nothing beyond that at this time.

25 Comments on “NTSB Testimony to the US Senate on safety, 787; FAA reviewing ETOPS

  1. I’ll agree- the FAA will NOT sign anything until the NTSB hearing- it would be Bcratic suicide.

    Note that the NTSB report claims the Boston Mechanic noticed FLAMES/FIRE outside of battery box. Which of course BA does NOT admit.

      • Thats sort of splitting hairs- the same as running tests using a resistor in place of real equipment for tests, and a VERY thin aluminum box, etc.

        along with testing ONE cell by driving a nail in it, and simply trying to ignite a propane inside of new boom box.

        All this when it was known that LI- cell ” fires” once started are self sustaining due to chemical reactions, etc

        Technically a glowing white hot pile of ” X” is not a fire, nor is a oxygen cutting torch used for decades a ‘ fire”, since there are no ” flames” . Keep in mind a major steel cutting reaction called thermite ( aluminum and iron filings ) is NOT a fire either !

        Molten- white/red hot “X” is a major hazard even in steel mills, let alone an aircraft in flight.

    • 600C – Internal temp of cell during a Li-ion thermal runaway failure
      2000C – Propane/Air flame temp
      2500C – Thermite reaction product liquid temp
      3500C – Acetylene/Oxygen flame temp

      Cutting torch uses a flame to heat material to cherry red temp. Then an oxygen blast is given which reacts with metal, producing enough additional heat to cut. A flame is indeed part of the cutting process.

      Chemical reaction between cathode and electrolyte solvent is indeed flameless, more like a smoldering reaction. However, factors of 3.3 to 5.8 in temperature sure seems like splitting hairs to me.

      • Most interesting item is available specific energy per specific heat capacity.
        i.e. what temp will the battery gain as an isolated “gob”
        ( If my numbers are reasonably correct avail. energy is 2kWh ~= 1/2lbs jetfuel plus the neccessary amount of oxygen to combust and not a couple of gramms of Butane/Air mix )

      • It’s a good thing the containment box will keep out the necessary O2 (for 1/2 lb of jet fuel equivalent).

      • Only to release that energy from the battery you just need to have it fault.
        No external oxygen required. Just force the battery into releasing it’s stored energy internally.
        ( This actually shows the super duper niceness of paired but separate storable oxydant/oxydiser energy sources like fuel + air/oxygen.

      • It’s also a good thing that, as measurements have shown, the worst thermal runaways (induced by nail puncture or crushing) release heat at a rate where the internal temperature reaches only about 600C. Much more manageable then sustained flame temps of 2000C to 3000C.

        Point is that the total heat released, and more importantly the maximum heat release rate, for large scale cell thermal runaway failures is fairly well characterized.

        Your 1/2 lb jet fuel example, while perhaps accurately reflecting the total available chemical energy, is misleading in that if properly mixed with oxygen, a detonation (extremely rapid heat release) could occur. A detonation, or even a rapid deflagration just does not happen with these batteries. The reaction times are way too long. What people call explosions with these batteries, is really just the case rupturing due to internal over-pressure after minutes of build-up.

        Boeing’s bench test involving purposeful propane ignition within the box is to test the box’s ability to withstand 3 times the design over-pressure. Other tests were performed involving the purposeful inducement of thermal runaway within the containment box.

        BTW, I’m not sure where you got your “couple of grams of Butane/Air mix” from. I don’t think Boeing or the FAA has released those test details.

      • “BTW, I’m not sure where you got your “couple of grams of Butane/Air mix” from. I don’t think Boeing or the FAA has released those test details.”

        You can only get so much stoichiometric butane/oxygen mixture into the calorimeter box.
        ( Even if you work with elevated pressure. 2C4H10 + 13O2 : box : 45l ~= 2mol, Butane is 2/15th of 2mol : 8_g_ Butane @ 1bar, Energy: ~136Wh

      • You’re right about that, at 1 bar fill pressure. One could vary the fill pressure, or the stoichiometry, or add dilluent to achieve the desired test conditions.

        Using an equivalence ratio of 1 with no or little diluent would insure a detonation. While this will easily produces the highest peak pressure for a given fill pressure, the pressure spike would be extremely short lived, and not representative of a real battery failure.

        My guess is that Boeing was trying to replicate the pressure time history (times 4.5) of a worst case thermal runaway in a vented box, using propane/oxygen combustion in a closed box.

      • In pure Heisenberg’s Uncertainty Principle style we have now the Boeing Quantum: a battery in a box that may or may not be burning at the same time

    • leehamnet :
      “Splitting hairs” is often “Boeing-speak.”

      Riiiight Boe-speak acronym is of course BS
      definitely NOT an oxy-moron !!

  2. From latest news, it seems that the grounding will be lifted(rightfully so).
    The FAA appear to be leaning towards a qualified ETOPS.
    I have a nasty feeling it may be less than 180 minutes pending in service experience.
    Just my 2c. worth, but that is my reading on current rhetoric.

  3. Looks like their is alot happening behind the scenes and the BFD (Boeing, not Boston Fire Department) is busy putting fires out wherever they see or even sense them to be starting.

    The big questions are:
    When will the FAA come to a decision (not necessarily approval) on the documentation that Boeing has presented it for “re-certifcation” of the battery system?
    Will the NTSB have any affect on this?
    Will the Japanese authourities automatically accept these findings?
    Will the FAA allow the 787 to go back into service with ETOPS 180 or less?
    What would the implications be if there are further battery events that the public become aware of, even if they are contained?
    What will the procedure be if a battery event does occur? (Emergency? Automatic redirect to nearest airport? Finish the flight? Other?
    How much pressure will the politicians apply (for or against either Boeing or the FAA)?

  4. If the flames really were all outside the battery box, isn’t a statement by anyone involved that there was no fire in the battery something to be welcomed? Something technically correct and honest for a change? And important given the way all of the non-specialist media (at least that I read) reported the incident as a ‘battery catching fire’ or similar.

    Of course, any failure to admit there were flames outside the box could be considered dishonesty by omission.

  5. One thing I keep meaning to ask. If the battery goes wrong mid flight (ie at a significant altitude) and ejects gunk out the new exhaust, is there any chance this gunk could cause injury/damage/fire where it lands?

    • I believe the vast majority of the “gunk” will be gaseous hydrocarbons at much less than the autoignition temperature. There was evidence that some electrolyte got out of the battery pack case on the side during the JAL incident, however it seemed that this material did not ignite. Even if some liquid electrolyte makes it out the vent tube (very unlikely), by the time it hits the ground it would not be noticeable if the aircraft is at cruise altitude. Just my opinion.

    • Good point!

      It is separate because the FAA will NOT grant battery certification unless Boeing can demonstrate less than once in 10 million flight hours for thermal runaway, and less than once in 1 billion flight hours for battery fire.

      The fire probability is extremely low, akin to the required probability of all flight controls plus back-ups failing.

      I’m afraid the ETOPS re-consideration has more to do with the overall reliability (perceived or real) of the 787.

  6. Don:
    “In pure Heisenberg’s Uncertainty Principle style we have now the Boeing Quantum: a battery in a box that may or may not be burning at the same time”

    A Schroedinger Quantum box. The fire is only there if you look for it inside.
    As long as the box is screwed shut and opaque there is no fire.

  7. Not sure where to stick this into the overall discussion. But what seems to be completely ignored in the past few months of battery-generated furor is the very real fact that the same week the battery incidents attracted enough attention to force the grounding, several significant fuel leak events occurred .. at least one in Tokyo and one at Boston.

    Without question the battery issues deserve every bit of the attention they have been getting, but as a former aircraft fuel systems technician, I submit that when fuel vales (or whatever the actual cause was) on a commercial airliner malfunction to the point fuel spills on the ramp, you have an equally significant safety situation.

    And equally significant ETOPS issues … keeping the battery from burning up is of little use if the fuel needed to reach the ETOPS diversion point all leaks out into the ocean on the way.

    The best coverage of the 787 battery issues I have found is here, hands down (thanks) … but what is being done to address the fuel system issues?

Leave a Reply

Your email address will not be published. Required fields are marked *