The Empirical Skeptic

Update

IFALPA says “Stop speculating about MH370

The Empirical Skeptic

Viewers of last night’s Air Crash Investigators program (Australia on Channel 7) have asked me many questions including:

  • Why didn’t we evacuate the A380 immediately after stopping on the runway in Singapore?
  • What are my views about the Malaysian incident?

My answers centre around how I gather, judge, store and use data.

Empirical Skeptic

I am an Empirical Skeptic.

Sully Sullenberger (stress tested and case hardened skeptic) and me.

Sully Sullenberger

I am motivated by facts, not by presumptions, assumptions, bias nor group think.    I assess new information for its authenticity, provenance and trustworthiness before judging whether to accept or to reject it.   In this regard I adopt Richard Dawkins’ view:

“That which can be asserted without evidence, can be dismissed without evidence.”

In today’s society where everyone with a mobile phone is a journalist, the Golden Hour has gone and there has never been a greater need for full and open disclosure and personal guarantees.   We should also remember Ronald Reagan’s words:

Trust but Verify”.

 So the next time you hear about something that scares you, look for data.  Be suspicious of absolute numbers that are provided without references, or no numbers at all.

QF32

Critics have commented: “de Crespigny should have evacuated the QF32 passengers quickly down the slides rather than delay and disembark them down the steps.   The fuel pooling under the aircraft should have caught fire”.

Constellation - painted by one of the world's best aviation artists - Jaak De Koninck  (www.jaakdekoninck.be)

Constellation – painted by one of the world’s best aviation artists – Jaak De Koninck (www.jaakdekoninck.be)

Roy Ford, my wonderful father-in-law often tells me:  those who “assume” make an “ass” of yo”u” and “me”.

We had a different reality on the “front line”. The firemen and ground engineers were our eyes and ears to the aircraft for the two long hours that we sat on the ground before the last passenger disembarked the aircraft. The firemen gave us information about the fuel leaks and any presence of fire.   They kept us informed.  We kept the passengers and crew informed.

We waited to be told if there was fire.   We were never told that there was fire.

We had assimilated much knowledge over our long careers that would perhaps become relevant:

We knew that the aircraft was certified to evacuate 873 passengers and crew through half the 16 exits in just 90 seconds.   In reality Airbus did not just satisfy this requirement, they excelled by evacuating everyone 12 seconds faster than certification required!   In our case we had all  16 exits available.  We carried only 440 passengers and 29 crew.  So theoretically, it could have taken between 21 to 25 seconds to evacuate 469 through all the doors.

Gasoline and jet fuel have very different qualities. Jet fuel is actually very hard to ignite and keep alight!

Source: ATSB  QF32 Report

  • Jet fuel has a “flash point” (fuel temperature at which vapour can be ignited) that is at least 80 degrees Celsius higher than the flash point of gasoline.
  • Jet fuel “blows out” like a candle flame in a wind of just 40 kmph.     Frank Whittle, the inventor of the gas turbine engine, discovered this as he was unable to stabilise flames inside his first engine until he enlisted Shell’s help.   Keeping the engine alight is still one of the greatest challenges in today’s latest generation jet engines.     Inside an A380’s $20m Rolls-Royce  Trent 900 engine in the cruise, the outside air must be slowed from 925 km/hr (500 knots) to swirl around each of the 20 fuel nozzles in the combustion chamber at no more than about 35 km/hr!  The F111’s classic dump and burn at Sydney’s Olympic Closing Ceremony, was only possible because the engines’ after-burners were engaged to  constantly ignite the jettisoned fuel.
  • A moving flame front over jet fuel spreads at only 10% of the speed that a flame front spreads over gasoline.   The “flame spread” speed of military, normal jet fuel and gasoline is about 6/30/230 metres per minute respectively.   The “Die Hard” fantasy film’s scene that showed a “fuse” of flame moving along a track of jet fuel training behind the hijacker’s aircraft is just that – fantasy!

    Anti static leads earth all fuel pipes to prevent static discharges (Photo ATSB Report)

    Inside one of QF32’s 11 fuel tanks.  Anti-static leads earth all fuel pipes to prevent static discharges.  Enlarge this image to view a fraction  of the massive shrapnel damage to the aircraft.   (Photo ATSB Report)

  • Jet fuel has a much higher electrical resistance than gasoline.   In our case this means that passengers walking through the pools of fuel can generate sufficient friction to create static discharges within that fuel.   The principle is the same as as the electrical discharge that you feel when you walk over carpet then press an elevator button.   Even the friction of jet fuel flowing through fuel pipes is sufficient to create discharges inside those pipes – hence the reason for the many grounding leads inside fuel tanks as per the photos opposite.  (Click here to see static discharges in volcanic plumes)

Eight fire trucks surrounded our aircraft.   The fire trucks were loaded with foam and water to extinguish fire around the aircraft and passengers.

Source: ATSB  QF32 Report

Trying to drown engine #1  (Source: ATSB QF32 Report)

Evacuations are dangerous.   My studies  show that about 15% of the passengers are injured when evacuating normal jet aircraft.   In our case, almost all our A380’s doors are higher than doors on normal aircraft.  We had elderly and wheelchair passengers and a toxic scene outside.

(Four percent of the passengers were injured in the latest Avro RJ100 passenger evacuation at London this week.  (RJ100 door sills are about one quarter as high as A380 door sills).

To evacuate or not to evacuate – that is the question

The previous points are relevant because we faced new threats when we stopped our A380 on the runway.  We needed different knowledge, training and experience to identify, rate and process these new risks and to make the best decisions.

The escape slide from the 3 story (8 metre) high upper deck door sill.  Rocket powered venturi pump inflates slides within 6 seconds (2/3 is fresh air).  Inflates within 6 seconds.  Withstands 25 kts (46 kmph) winds.

The escape slide from the 3 story (8 metre) high upper deck door sill. Rocket powered venturi pump inflates slide within 6 seconds (2/3 is fresh air). Withstands 25 kts (46 kmph) wind blasts.

We faced two significant threats; the possibility of fire and the toxic environment outside if we evacuated down the slides.  Timing was critical.

  • If fire had been confirmed, then we were prepared to evacuate the passengers down the slides under the protection from the eight fire trucks and emergency services.   It’s not a pretty thought of the elderly and wheel chair passengers jumping onto, then sliding down a 45 degree sloped slide from an 8 metre (3 story) high floor.
  • We tried to mitigate the toxic environment outside the aircraft.   We called for aircraft steps to avoid the injuries that would result from an evacuation using the slides.   We also  requested buses to ensure that we would keep the passengers away from the pooling fuel, the running engines and the fire trucks.  We tried to shut down number one engine that was still running.  Fire services was spreading foam over the spilled fuel and water over the hot brakes.

The threats reduced rapidly as the fire services covered the fuel and cooled the brakes.   The passengers and crew were still safer on board our aircraft than outside the aircraft.

The rest is history.  There were no injuries.

Armchair Quarterbacks

Building  a plan in the absence of facts can result in incorrect decisions and actions and potentially dangerous outcomes.

QF32 Brake Temperatures after stopping.   (Source ATSB Report)

QF32’s Brake Temperatures after stopping.   Brakes 1, 2, 5 & 6 are located on the left wing gear.  (The left body brakes (9, 10, 13 & 14) absorbed more energy as a consequence.   (Source ATSB Report page 240)

Just before my book went to print, the ATSB informed me that after we had stopped, that the four brakes on the left wing slightly inboard from Engine 2 (and under the fuel leaks) were COLD.    All four brakes were between 30-40 degrees (ambient) Celsius!

Source: ATSB  QF32 Report

Source: ATSB QF32 Report

We did not know on the day of the event that these brakes were cold.  We didn’t know that the brake’s sensors and wires had been damaged by the explosions.  We did not know that these four brakes would also be 100% useless for stopping us on the runway that day – but that discussion is for another day.

I was not able to include this information about the COLD brakes in my book “QF32″.   It would have been a Criminal Offence to release this privileged information before the ATSB published its Final Report on QF32.   The left wing brake temperatures are now shown in the ATSB report at page 240 – although the reader would have to look carefully to notice it, and few have.

We reacted to the enemy (threats) that faced us on the ground that day; what we saw, what we knew, but never what was presumed.     We did not presume that a fire was present or that it would erupt.    We wanted proof.   We knew the environment was toxic outside the aircraft, so we mitigated the threats.

300 KVA in 6 phases of 115Volt AC power  cables cut and shorted.   AC  (Photo: ATSB QF32 Report)

300 KVA in 6 phases of 115Volt AC power cables cut and shorted. AC (Photo: ATSB QF32 Report)

How many passengers and crew would have been injured if  we had evacuated on the presumption that there would be a fire?

Reflection

It’s now three years after QF32 and only a few weeks after the shocking Malaysian tragedy.

I share the world’s grief.

I am continually asked: “what do you think?”

My answer has never changed:  I’m an Empirical Skeptic.   I react only to facts and I don’t have enough facts!

I don’t know!

I’ll then repeat these guiding words from Robert Heinlein:

What are the facts? Again and again and again — what are the facts? Shun wishful thinking, ignore divine revelation, forget what “the stars foretell,” avoid opinion, care not what the neighbors think, never mind the unguessable “verdict of history”

What are the facts, and to how many decimal places?

You pilot always into an unknown future; facts are your single clue. Get the facts! 

See also

The Golden Hour

The Media Circus around MH370

IFALPA says “Stop speculating about MH370

Delivery team for VH-OQD "Fergus McMaster" (QF founder & first Chairman)  delivered SIN-SYD 24 Aug 2009.

Delivery team for VH-OQD “Fergus McMaster” (QF founder & first Chairman) delivered SIN-SYD 24 Aug 2009.

7 comments

  1. Mat Williamson · · Reply

    As a career firefighter myself, (and hopefully a good pilot one day, as I am currently learning to fly!) your decision to keep passengers on board was an extremely wise move.

    Being that you were surrounded by 8 foam producing Fire Appliances, your Aircraft, crew and passengers were in the ‘great hands’ of the Firefighters.

    Safe travels!

  2. Howard Shaw · · Reply

    Hi Richard,

    I had a couple of thoughts after reading this:

    Firstly I didn’t realise gasoline was more volatile than jet fuel! I was on a train a few years ago in the UK, which had a diesel powered 1960s locomotive. It hit an object vandals had left on the track, and it punctured the fuel tank, which then leaked on the tracks as the train passed over. The train stopped, the lights went out, there was this overpowering smell of diesel, and when people realised what had happened everyone wanted off. The train guard, a tiny middled aged Yorkshire woman, put her hi vis jacket on, got out her loudhailer and YELLED at everyone to stay put- that there was no way it would ignite, and that we’d be in far more danger if we had to climb onto the tracks, with every chance of being hit by other trains. It worked, everyone calmed down. It reminded me when I read your book of the role that Michael (or is it Klaus?!) played. I think it is also a point that crews are paid first and foremost to guarantee safety and people should be very sceptical of attempts by managers to cut back on their numbers, salaries, or training.

    I have two questions about the aircraft ‘Nancy Bird Walton’ firstly, I read it is now heavier than other A380s and isn’t used as much as the others, is this correct? Secondly, you said that an RR engine needs a full rebuild after ingesting foam- did they do that for your engine one or write it off?

    Also- for those who often ask you why you failed your route-check, you answer this question when you say that ‘if the check captain has to intervene, you fail’ they had to intervene, not your fault of course, but they did, so i guess they would have rescheduled you another one when you were back in normal service- is that right?

    Best wishes.

    Howard Shaw, Berkshire, England

    1. Thanks for your story Howard. Yours is a great case study for those who work with fuel. It also supports my thesis of the differing threats that gasoline, jet fuel and diesel present and their influence on a decision whether to evacuate or not to evacuate.

      Diesel has a flash point temperature of about 52 degrees Celsius, about 92 degrees C higher than gasoline and 17 degrees C higher than Jet Fuel!

      I have a brother in law who worked his farm for forty years. He stated that if you aimed an oxy torch into a tub of diesel, that it would not ignite until the diesel started boiling! This gives great support to your very wise train guard.

      Nancy-Bird Walton (VH-OQA) was only about 94 kg heavier than a new aircraft so the performance was practically identical to the rest of our A380 fleet. Nancy travels on any-all routes with the other A380s. (It was probably the longest and most expensive repair in aviation history. I’ll write a blog about the repair if there is interest.)

      Engine number one needed a complete rebuild at a cost of $14m. The tiny ventilation-cooling ducts in the HP turbine blades would have been clogged by foam injected into the engine. Ditto for probably every other orifice. This is exactly why injecting foam into engine #1 to kill it was the least preferred and last option and why the engine then needed 100% disassembly.

      Cheers

      Rich

  3. Shikhar Joshi · · Reply

    Everybody is a reviewer today. Everybody is a journalist today. Sad.

    1. Shikhar Joshi · · Reply

      Someone has said it right, “Half knowledge is more dangerous than No Knowledge “.

  4. Adam Troy · · Reply

    To the skeptics I say “Go and watch the movie ‘The Right Stuff'”. Knowledge was gained by trial and error. Knowledge built upon knowledge and became “fact” not speculation.

    Today’s pilots have learned from this proud tradition that cost many men’s lives. They paid it forward so we might fly safely in the future.

    I have read QF32 and I feel very secure with men like Captain de Crespigny in command, a man who has the “Right Stuff”.

  5. Paul Seaman · · Reply

    Hi Richard,

    Excellent summary of your thinking.

    The easiest thing in the world is to be an armchair critic. The power of hindsight, and some ignorance of the actual facts, makes for easy judgement.

    That you made those decisions on the spot (with input from your crew) and under real pressure, but in hindsight, do not back away from those decisions says plenty.

    An aircraft’s Captain is responsible for delivering their passengers safely at the final destination. Your judgement, in extreme circumstances, enabled that to happen. Job well done I’d say.

    Regards
    Paul

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