Within 90 days from the receipt of this letter, develop a policy that would require the installation of aural minimum safe altitude warning (MSAW) equipment in those visual flight rules terminal facilities that receive radar information from a host radar control facility and would otherwise receive only a visual MSAW alert.
On February 21, 1996, the FAA stated that it would conduct a cost-benefit analysis to determine the feasibility of implementing this safety recommendation. The FAA further stated that the analysis would be completed by the end of March 1996. In June 1996, the FAA completed the cost-benefit analysis and determined that it was feasible to implement the recommendation. The FAA expected that implementation would be accomplished by the end of March 1997.
In its July 15, 1996, letter to the FAA, the Safety Board stated that, although the FAA's implementation of the requirement for the aural alert was not accomplished within the 90 days specified in the safety recommendation, the Board was pleased that the FAA had proceeded with the implementation. The Board indicated that it would wait to receive a list of the affected facilities and anticipated installation dates.
On July 31, 1997, the FAA stated that it had conducted a survey to determine the total number of ATC facilities that did not have aural MSAW alerts installed. The FAA found that 43 remote displays had been equipped with aural alarms but that 69 remote displays did not have aural alarms. The FAA anticipated that the aural alarms at those 69 remote displays would be implemented by February 1998.
On December 30, 1997, the Safety Board said that it was encouraged that the FAA was moving forward and urged the FAA to keep the program on track and within its anticipated milestones. On May 14, 1998, the FAA said that, as of April 10, 1998, kits had been delivered to all 69 remote sites and that all alarms would be operational during May 1998. However, at the Safety Board's public hearing in March 1998, the FAA's Deputy Director for Air Traffic Operations testified that the new projected completion date for installation of aural alarms at VFR towers, including the tower at Guam, was April 2000.
On October 19, 1998, the Safety Board stated that the primary intent of this recommendation was to ensure that VFR tower controllers who have a visual representation from a distant host radar receive an aural alert when aircraft under their control and with whom they are in radio communication descend below the minimum safe altitude. If the tower controller was engaged in visually scanning for other aircraft, the aural alert would allow the controller to determine the aircraft call sign and transmit the appropriate warning to the pilot. The Board's letter indicated that the FAA was unclear about whether controllers at VFR terminal facilities would receive an aural alert for those aircraft with whom they are in communication. Further, Safety Board staff had determined that, in at least one location, the VFR tower would not receive an aural warning. (The Board's letter did not identify the location of this facility.) The Board requested that the FAA ensure that controllers at all VFR towers with visual representation systems from a distant host radar receive an aural alert when aircraft within their traffic pattern and with whom they are in communication descend below the minimum safe altitude. Pending the
