12. Lesson: Detailed Scheduling of Work
All fabrication, assembly, and checkout activities should be scheduled in detail, but rescheduled activities (sometimes called unscheduled work) should be even more carefully controlled and scheduled.
Background:
In a development program involving many elements being supplied from a variety of sources, it is inevitable that some components are not available when scheduled. More than likely, these late components will be rescheduled for weekend, third shift, or slack time installation. Such off-time activities can become uncontrolled since the normal flow of work is interrupted and the configuration is not that originally postulated by the planning staff. The situation, schedule pressure, incomplete planning, and unknown configuration lends itself very well to errors and mistakes. This is precisely the time not to take shortcuts in planning or in documentation.
The workshop was particularly susceptible since it had been most affected by the change from the wet workshop to the dry workshop configuration and was, therefore, the last module to be completely defined. Items were quite late in fabrication and there were many instances of off-line installation. The original installation procedure was developed assuming properly phased activities. When the part was actually installed, frequently, the original procedure could not be used and additional time was lost while a new procedure was developed.
Caution: Never permit off-line installation to be accomplished without a written procedure. The same controls must exist for off-line work as for in-line work.
These lessons learned are from SKYLAB LESSONS LEARNED AS APPLICABLE TO A LARGE SPACE STATION, A dissertation submitted to the faculty of The School of Engineering and Architecture Of the Catholic University of America For the Degree Doctor of Engineering by William C. Schneider, Washington, D.C., 1976.
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