James Madison
Apollo 12 - A Study in Engineering Diligence
by James Madison


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James Madison

Thirty-six seconds after liftoff, the Apollo 12 spacecraft was struck by lightning.  The resulting power surge caused instrument malfunction, communication system failure, and telemetry data distortion. Mission control engineers on the ground scrambled to find solutions.  The flight director prepared to abort the mission.

Engineer John Aaron calmly instructed the astronauts, "Flight, try SCE to 'Aux'".  Aaron's fellow mission control engineers were baffled.  The flight director on the ground and the communications astronaut in the spacecraft asked Aaron to repeat the instruction.

"What the hell is that?" asked one of the astronauts in the crippled spacecraft still heading blindly into space at an ever-increasing speed.  Only one astronaut even knew where the switch was.  He reach over his shoulder to an obscure location on the instrument panel and flipped the SCE switch to the Auxiliary position.

Instrumentation returned to normal.  All communications resumed.  Flight telemetry came back online.  It was as if the incident never occurred.  The flight went on to carry out its mission and return the astronauts safely home.

How was Aaron able to save the day when everyone else was ready to fail the mission?

A year before the flight, Aaron was performing tests at Kennedy Space Center when he noticed unusual telemetry readings.  Of his own initiative, he traced this anomaly back to the obscure Signal Conditioning Equipment (SCE) system, and became one of the few flight controllers familiar with it.  He found that normal readings could be restored by putting the SCE on its auxiliary setting, allowing it to run under low-voltage conditions.  During the crisis, Aaron hypothesized that this setting would also return the Apollo 12 telemetry to normal and instructed the astronauts to try it.

This story contains critical lessons for engineers in demanding technical roles:

         Know your systems.  Aaron encountered the anomaly during testing over a year earlier.  He explored it with sufficient depth to understand its observable characteristics and systemic implications.  He did this of his own initiative.  Testing may be the dullest part of engineering, but it's far better than ignorance in a crisis.

         Embrace exceptions.  He could have just treated the testing anomaly as an outlier and ignored it.  Instead, he dug into it, learning important details about the system.  Crisis, almost by definition, is exception based.  Exceptions are not an interruption of testing--they are the purpose of it.

         Think under pressure.  He understood the facts as they were unfolding and connected them to other facts from his experience, despite the very different root cause--lightening strike was never a tested scenario.  He did this in real-time, with consequences that could have included the death of the astronouts.

         Lead in the face of doubt.  Except for one astronaut, no one even understood Aaron's instruction, let alone its implications and importance.  But Aaron advocated what he believed was right.  For all we know, Aaron may have even doubted himself--this was a never-tested solution to the never-tested problem.  But he called the shot.

May we all do so well in turning routine testing into critical knowledge, investigating the unusual, staying focused in a crisis, and taking the lead when we may be the only one who can save the day.


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