Reprinted from The New Rational Manager, by Charles H. Kepner and Benjamin B. Tregoe
Princeton Research Press, Princeton, NJ, 1991, 1997.
问题分析的最佳使用是最有效的使用。如果简短的、非正式的使用思路能够揭示出问题的原因，那么一味地坚持整个过程中的每一个步骤并没有什么特别的好处。事实上，人们使用问题分析的时间越长，他们就越善于挑选出适用于他们每天面临的各种问题的过程片段。当人们开始问一些问题，比如 "最近这个操作的时间有什么变化吗？"或者 "就在你注意到问题之前，这个过程处于什么阶段？"他们已经完成了对问题分析技术的学术欣赏和对其在日常问题解决中的实际作用的内部化之间的过渡。
This is especially true of the abbreviated application of the process. The seriousness of a problem does not necessarily determine the length or complexity of the analysis required to resolve it. Some extremely serious problems have been solved through abbreviated uses of the process. They were so data-poor that full use could not be undertaken. Fragments of the process had to be relied on and combined with educated speculation to arrive at a most likely cause.
Fifty-four hours and fifty-two minutes into the mission—205,000 miles from earth—and all was well. Then John L. Swigert, Jr., duty commander at the time, reported: “Houston, we’ve got a problem here…. We’ve had a Main Buss B undervolt.” This was an insider’s way of saying that electrical voltage on the second of two power generating systems had fallen off and a warning light had appeared. A moment later the power came up again. Swigert reported: “The voltage is looking good. And we had a pretty large bang associated with the caution and warning there.” Three minutes later, as the dimensions of the problem became clearer, he reported: “Yeah, we got a Main Buss A undervolt too….It’s reading about 25½. Main B is reading zip right now.”
尽管当时没有人能够想象到是什么原因导致了氧气罐的爆裂，但 "二号低温氧气罐的破裂 "可以解释电压的突然丧失和随后的压力损失。
Further actions were taken to conserve both oxygen and electricity. A number of “IS…COULD BE but IS NOT” questions were asked to get further data, and a series of system checks was undertaken to verify cause. In the end it was determined that the Number Two Tank had burst and vented all its oxygen, plus a large portion of the gas from the Number One Tank, through a damaged valve and out into space.
It was weeks before the root cause of this problem was established through on-the-ground testing and experimentation. Two weeks before the launch, a ground crew had piped liquid oxygen into the tanks in a countdown demonstration. After the test they had had difficulty getting the oxygen out of the Number Two Tank. They had activated a heater inside the tank to vaporize some of the liquid oxygen, thus providing pressure to force it out. They had kept the heater on for eight hours, longer than it had ever been used before. Although a protective switch was provided to turn off the heater before it became too hot, the switch was fused in the ON position because the ground crew had connected it to a 65-volt power supply instead of the 28-volt supply used in Apollo XIII. Later, in flight, the crew turned the heater on briefly to get an accurate quantity reading. The fused switch created an arc that overheated the oxygen in the tank, raised the internal pressure tremendously, and blew the dome and much of the connecting piping off into space.
他们测试了原因--二号油箱破裂，发现这可以解释说明书中描述的突然性和整体性。这也可以解释在第一次低电压指示时报告的爆炸声，飞行人员感觉到的阿波罗十三号的颤抖，以及 "有东西......流向太空 "的排放。这既说明了他们积累的IS数据，也说明了他们的监测活动中出现的IS NOT信息。更重要的是，它解释了系统内的一个突然的、完全的故障。
They had unbounded faith in Apollo equipment, knowing that it was the best that could be devised. The idea of an oxygen tank bursting open in the depths of space was not credible. All this was justified from their experience. Without the bungling that had occurred on the ground two weeks before the launch, the tank would have gone to the moon and back just as it was designed and built to do. However, the Houston engineers stuck to the Problem Analysis process despite their incredulity, believing that the test for cause they had carried out had provided the correct answer. In fact, they proved this cause in record time. What saved the day was their knowledge of Apollo XIII’s systems and of what could produce the exact kind of sudden failure that had occurred.
In a case such as this, Problem Analysis is rendered difficult by two factors: secondary effects and panic. Sudden failure in a complex system usually causes other deviations that may obscure the original deviation. The shock of a sudden failure often precipitates panic, making a careful review and use of the facts even more difficult. A disciplined and systematic investigation is difficult in any case, but discipline becomes essential when a top-speed search for cause is undertaken and there is no possibility of amassing all the data that would be optimal in the investigation.