This, according to the author, is precisely the reason for the accident. When the controller noticed the two aircraft in the same altitude range, he was distracted by the malfunctioning phone system, while the other controller was having a break. Nobody was there to help with the extra workload, causing the fatal delay. Human factors relating to the air traffic control crew therefore include the need to take breaks, the tendency to be distracted and the tendency to make incorrect decisions.

It is also interesting to note that the on-board conflict alert systems were functioning properly, but the pilots were waiting for confirmation from traffic control to take action. Had a more distributive paradigm been implemented, the pilots may have been able to share some of the burden of traffic control and avoided collision.

Another interesting aspect of human error is the management of air traffic control. In addition to an unwillingness to investigate the accident for avoiding such cases in the future, Brown also mentions that the FAA could do much to improve...

He suggests better management of the air traffic controller issue. This can be remedied by the above-mentioned integration of controllers and pilots in sharing the responsibility for conflict alert and preventative action.
Many lessons can be learned from accidents such as those cited above. The most important one is that even state of the art technology is not enough to ensure a safe flight. It requires the complex integration of both humanity and technology.

Sources

Air Safety Week (2004, May 31). Human Failings Underscored in Report of 2002 Mid-Air Collision Over Germany. Online database: FindArticles.com

Brown, Don. (2005, Dec. 7). Say Again? #57: uberlingen. AVweb.

A www.avweb.com/news/sayagain/191072-1.html

Kelly, Wallace E. (1999, Oct. 24-29). Conflict Detection and Alerting for Separation Assurance Systems. Draft for 18th Digital Avionics Systems Conference. St. Louis, Missouri. http://www.bluerockresearch.com/papers/dasc_kelly.pdf