Energy Issues

 Vol. 233 No. 4

It was two years ago this month that BP’s Macondo well blew out, leaving 11 dead, a huge swath of pollution in the Gulf of Mexico and a stain on our industry that may take decades to erase. It doesn’t seem that long ago and, yet, it seems like years. In the interim, many things have changed. We have new regulations and operating procedures, voluminous reports, increased negative visibility, new oversight agencies and numerous additional things we did not have in our lives before. One is a new commitment to operational safety and stewardship. These are well and good. But, there is something else that we can’t shake.

Any review of the numerous Macondo reports makes it apparent that the overriding, undeniable and ultimate cause of the event was human error. To be sure, equipment failed, but it failed only after being subjected to forces it was never designed for—because of human error. Some have called the cement job into question. Whether it failed or not, and how, is still a matter of debate. If it did fail, it was because of human factors. The rush to finish the well and move to another location meant that the cementing program was not fully examined and the risk of failure not fully weighed. Nor, for that matter, was the liner design.

Not long after the disaster, I was asked to join a team to moderate an SPE-sponsored meeting that discussed the causes of the disaster in preparation for a report that, eventually, was destined for the U.S. Department of the Interior. We divided into several groups. My group was asked to look at the human dimension of the disaster. I can tell you now that we struggled. There was not a human engineer among us. Motivations, lapses in judgment and the like were not our area of understanding. How we wanted to talk about BOP actuators, kill procedures and such. But, we struggled through it. And, I subsequently found, we were not alone. Humans have a tendency to suspend prudent judgment when faced with deadlines mandated from above, whether they be real or imaginary.

I discovered just how large this brotherhood of non-critical adherents to schedules is when a friend gave me a book written by Mike Mullane, a former astronaut. Entitled Riding Rockets, the book details in alarming clarity the consequences of suspending better judgment to meet schedules, and achieve real and imaginary goals. It has cost the U.S. two space shuttles and their crews.

The first, Challenger, was launched despite advice to the contrary from the makers of the solid fuel boosters, which caused the accident. The boosters were comprised of several segments, loaded with solid propellant, which were bolted together with the seams sealed with an inner and outer O-ring. In a number of previous launches, it had been noted that some of the seals had leaked superheated gasses, though nothing serious had happened. Challenger was slated for launch in the dead of winter, with an anticipated temperature in the 20s°F on launch day. Experts from Thiokol, the manufacturer of the solid rocket boosters (SRB), warned that there would be O-ring shrinkage at those temperatures that might endanger the rockets and the spacecraft. Their warnings were dismissed, in a large part, to keep the shuttle project on track.

Those of you who remember the day in January 1986, or have read about it, know what came next. The O-rings failed, causing a breach in the SRB joint it sealed, allowing pressurized hot gas from within the solid rocket motor to reach the outside and impinge upon the adjacent SRB attachment hardware and external fuel tank. This led to the separation of the right-hand SRB’s aft attachment and the structural failure of the external tank. Aerodynamic forces promptly broke up the orbiter. The command module, containing the crew, was propelled upward several miles before beginning an agonizing plunge to the sea with the astronauts aboard and, apparently, very much alive—until they hit the surface of the Atlantic Ocean at 250 mph.

Do you think that this was enough to prompt a conservative attitude at the National Aeronautics and Space Administration (NASA)? Think again. Think of Columbia, the second doomed shuttle. Fast forward to February 2003. The loss of Columbia was a result of damage sustained during launch, when a piece of foam insulation the size of a small briefcase broke off from the external tank (ET), the main propellant tank under the aerodynamic forces of launch. The debris struck the leading edge of the left wing, damaging the shuttle’s thermal protection system, which shields it from the intense heat generated from atmospheric compression during re-entry. As the shuttle descended toward a landing in Florida, intense reentry heat flowed into the damaged left wing, which disintegrated, resulting in the complete breakup of the shuttle and the loss of another seven brave souls.

The majority of prior shuttle launches recorded such foam strikes and thermal tile scarring. On STS-112, two launches before, a chunk of foam broke away from the ET bipod ramp and hit the SRB-ET attach ring near the bottom of the left solid rocket booster, causing a dent four inches wide and three inches deep. After that mission, the situation was analyzed and NASA decided to press ahead under the justification that “the ET is safe to fly with no new concerns (and no added risk)” of further foam strikes. Of course, at that point, the shuttle program was seriously behind schedule and under pressure to catch up.

Human failure is not a pretty picture, but it is not reserved for special situations. It is all around us. And, thus far, we can’t engineer for it—but we must.