Regional Jet 700 ER/LR (CRJ700)
Air Traffic Control Fully Certified
Other / Unknown
ATC Issue All Types; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT
Flight Crew Took Evasive Action
Aircraft; Procedure
A CRJ7 was cleared for; and established on; the ILS PRM Runway 10. The CRJ7 was level at 030 and approaching point to switch to Tower frequency when the pilot notified me he was responding to a terrain warning. I instructed him to maintain at or below 040 because of traffic on adjacent finals. I then instructed the pilot to track the localized and simultaneously observed the aircraft drifting off the localizer toward the other final. I then instructed the CRJ7 to turn right to a 120 heading in an attempt to achieve separation. Soon after the pilot stated that they had recaptured the localizer. I recleared the CRJ7 for the approach and kept the pilot on my frequency to ensure they were settled on the approach before switching to Tower frequency.
A80 Controller described a terrain warning event during simultaneous PRM approaches to Runway 10; the reporter noting the aircraft was initially not established on the localizer.