December 21 1989 – March 20 1990
MacPhail, Ian
March 21 – June 20 1990
Crowley Jr., Webster R., Hess, William J.
September 21 – December 20 1990
Clark, Ross C.
December 21 1990 – March 20 1991
Simonds, O. C.
March 21 – June 20 1991
van der Linden, Peter J.
June 21 – September 20 1991
Sundberg, Walter J., Mueller, Gregory M.
June 21 – September 20 1991
Clark, Ross C., Bachtell, Kris
September 21 – December 20 1991
Nachel, Jim
December 21 1991 – March 20 1992
Doty, Carol L.
March 21 – June 20 1992
Johnson, Craig B., Rosenthal, Marcia W.
June 21 – September 20 1992
Winter, Kendall, Crowley Jr., Webster R., Hess, William J.
June 21 – September 20 1992
Kalata, Lynne
December 21 1992 – March 20 1993
Crowley Jr., Webster R.