Analysis of data recorded from TCAS I equipped aircraft indicated that the TCAS I interference limiting algorithms were causing acquisition of intruders at low ranges and that the tracks were often intermittent. This change enhances the minimum TCAS I surveillance performance by refining the assumptions used in development of the original interference limiting algorithms. These modifications provide a significant operational benefit to the operators of TCAS I equipment, without increasing the total amount of interrogation power transmitted by TCAS I equipped aircraft. Power is reallocated to more closely reflect the actual operating environment