This paper contains an assessment of the stability of MLS angle antennas. The analysis contains a breakdown of the MLS angle error budget, from the system error to the ground equipment, environment, and propagation error sources. An assessment is made of MLS field data collected over a 12 month period from the Hazeltine Model 2600 MLS installed at the FAA Technical Center in Atlantic City, New Jersey. A statistical analysis is performed on the field data and a comparison is made to the ground equipment error budget allocation.