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The authority gradient

October 20, 2006

Man-made disasters fascinate me.  Why was the space shuttle Challenger allowed to take off in conditions that violated NASA’s own rules?  How is it that captains of industry failed to consult an engineer on the condition of their dam on the South Fork of the Little Conemaugh river in Pennsylvania, ultimately obliterating Johnstown in 1889?  How did a mishandled safety test cause the worst nuclear accident in history?  Over the years I’ve read dozens of books about such events both large and small.

So naturally I taped Nova: The Deadliest Plane Crash on Tuesday night.  The episode set out to answer just how, on a fog-shrouded runway in the Canary Islands in 1977, did two fully-loaded 747 aircraft collide, killing nearly 600 people?

Pilot error, as it turned out, but the pilot who made the biggest error was KLM’s most experienced guy.  He trained other pilots and was so respected that KLM featured him in their adverts.  He was stone-cold sober and there was nothing bad going on in his life.  His lifetime of rationalism and care just… missed.

So what the hell happened?

Nova did a fantastic job presenting the sequence of events that led to the flaming horror.  I would love to have the episode shown in high school classes, tying together many areas of working life:

  • The Spanish separatist bomb that closed the airport both the planes (and many others) were supposed to use, diverting them to a smaller airport that could not handle their passengers

  • Economic pressures to take off again as soon as possible
  • The role played by passenger dissatisfaction
  • Sheer bad luck that the two 747’s were blocking the runway entrance from the other planes
  • The KLM pilot’s decision to fuel, not just for the short hop to a nearby island, but for the subsequent trip to the Netherlands
  • Overworked, underprepared tower crew, whose non-standard terminology contributed to miscommunication between the two planes and the tower
  • The narrow, poorly-marked runway at the small airport
  • Horrible timing of the weather, dropping visibility to less than 500 meters in a few minutes
  • Overlapping radio signals that obliterated two crucial pieces of information
  • The role of “cockpit culture”, which was found to have prevented the last, most important communication that would have saved all those people in spite of the other factors.

That last item was the most interesting.  Few man-made disasters are the result of a split-second of inattention.  Usually a number of factors, individually quite improbable, must line up like the pins in a lock tumbler for the last, fatal mistake to make history.

Nova described the “authority gradient” of cockpit culture 30 years ago.  The Captain sat atop a more or less Olympian pedestal, pretty much immune from criticism.  Co-pilots and crew were not encouraged to question the Captain’s actions; indeed, to do so was to risk one’s career.  The more exalted the pilot’s reputation, the less anyone could say anything.

The Pan Am pilot made minor mistakes navigating in the fog and communicating with the tower.  The tower made minor mistakes communicating with both planes (and in listening to a soccer game while 600 lives hung in the balance).  And the KLM pilot, perhaps believing he had been given clearance to take off, powered up his engines…

“No!” said the co-pilot.  “We have not been given clearance to take off!”

The most senior, experienced pilot, chagrined, powers down.  There is more chatter.  Then he powers back up again, starting his plane down the runway in the dense fog…

1706:32.43 KLM 3 Is he not clear, then?
1706:34.10 KLM 1 What do you say?
1706:34.15 PA ? Yup.
1706:34.70 KLM 3 Is he not clear, that Pan American?
1706:35.70 KLM 1 Oh, yes. [emphatically]

Perhaps because of the KLM pilot’s very senior position, neither the copilot nor flight engineer questions the pilot again, and the impact occurs about 13 seconds later. Based on the Pan Am cockpit voice recording, investigators determined that the Pan Am flight crew saw the KLM coming at them out of the fog about nine seconds before impact. The Pan Am captain says “There he is … look at him! Goddamn, that [expletive deleted] is coming!” and his copilot yells “Get off! Get off! Get off!” The Pan Am pilot guns the engines but it’s too late. At 1706:47.44, the KLM pilot screams, and the collision occurs.
- Deadliest Plane Crash, Final Eight Minutes

When powering up the engines a second time, an opportunity existed to avoid the crash.  Clearance to take off had not been given, and both the co-pilot and flight engineer knew it.  But no further objection is made until the plane is hurtling down the runway at almost takeoff speed.

There are few good models for organizations to function with no authority gradient.  Extremely experienced, capable people are nearly always right, in a setting where being wrong can have terrible consequences.  But that is exactly the point; even a brilliant, experienced pilot can have one moment off his peak. In fact, it probably happens fairly often.  Usually, the moment passes without incident.  But if enough problems line up, and the authority gradient is too steep…

According to Nova, pilot training has changed in the years since the accident.  The authority gradient has been somewhat levelled.  Now pilots are taught to encourage questions or even negative feedback from crew.  The importance of dissent is proportional to the lives that hang in the balance.

I have seen this same phenomenon in one case study after another: the trusted, authoritative leaders were simply too powerful, or feared, or trusted, or even beloved to question, or did not conceive themselves as ever being mistaken, and the mind-blowing, catastrophic mistake that follows. 

The nagging voice of doubt is seldom popular, but it’s often a crucial view from another angle.

  1. Ed
    October 21, 2006 at 09:23 | #1

    Maybe we could import the “revised” cockpit culture of today (where all inputs are considered and there is no penalty for challenging the captain) into our political structure.  Then one wouldn’t be branded as a terrorist for dissent.

    This particular episode of NOVA was a keeper, BTW.

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