Derived at Station Y in April 1989 using 572 transit satellite passes. Computed value for dZ was -96.42 but -96.38 has been utilised. Replaced Malongo 1987 to WGS 84 (3) (code 15791) in 1989. Replaced by Malongo 1987 to WGS 84 (2) (code 1557) in 1990.