fire was started in a tank.The root of this accident can be traced back to 1966, when the Beech Aircraft Corp. manufactured Tank No. 2. According to NASA, acceptance testing showed that heat was leaking into the tank at a higher rate than specifications permitted. After some reworking, the leakage was reduced, but was still considered to be unacceptable by the agency. "The tank was finally accepted after a formal waiver of this discrepancy." Several other discrepancies that were regarded as minor by space agency inspectors were also accepted, according to NASA. These included oversized holes in the tank dome and electrical plug support and an oversized rivet hole in the heater assembly just above the lower fan. None of these items was regarded as serious in 1966 and none had anything to do with the explosion 4 years later. But they were symptomatic of a tendency toward oversight in which a more serious discrepancy could occur, undetected.After it was shipped to North America, Tank No. 2, serial number 10024X-TA0009 , was first installed in service module 106 for the flight of Apollo 10. However, Tank No. 2 was removed from this flight because of a decision by NASA to modify vacuum pump on the tank dome. The modification required the removal of the oxygen tanks and the shelf on which they were mounted in the Service Module. As Tank No. 2 was being removed, it was accidentally dropped about 2 inches. Testing showed this accident caused no apparent damage to the tank. After the vacuum pump modifications, the tank was installed in service module 109 for the flight of Apollo 13.Several weeks before each Apollo launch at the Kennedy Space Center, a countdown demonstration test series is carried out to detect any problems before the final countdown starts. During the demonstration test for Apollo 13, ground crews reported a problem in Tank No. 2. It could be filled normally, but could not be emptied in the normal way, by pumpin...
