Narrative:

The APU was deferred inoperative at ZZZ1. During approach at ZZZ; the right generator drive light illuminated. We referred to checklist which led to disconnect of the CSD. Since we were down to 1 generator and the checklist said to land as soon as conditions permit; I declared an emergency with traffic priority and landed at ZZZ runway 17L. Another factor in my decision was approaching thunderstorms that were threatening to shut the field down. I felt that traffic priority was important in event that the field was shut down and had to divert to altitude with only 1 generator.

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Original NASA ASRS Text

Title: DISPATCHED WITH AN INOPERATIVE APU; B757-200 FLT CREW DECLARED EMERGENCY IN ARR ARPT TERMINAL AREA WHEN A RIGHT GENERATOR DRIVE LIGHT REQUIRED THE SHUTDOWN OF THE RIGHT GENERATOR.

Narrative: THE APU WAS DEFERRED INOP AT ZZZ1. DURING APCH AT ZZZ; THE R GENERATOR DRIVE LIGHT ILLUMINATED. WE REFERRED TO CHKLIST WHICH LED TO DISCONNECT OF THE CSD. SINCE WE WERE DOWN TO 1 GENERATOR AND THE CHKLIST SAID TO LAND AS SOON AS CONDITIONS PERMIT; I DECLARED AN EMER WITH TFC PRIORITY AND LANDED AT ZZZ RWY 17L. ANOTHER FACTOR IN MY DECISION WAS APCHING TSTMS THAT WERE THREATENING TO SHUT THE FIELD DOWN. I FELT THAT TFC PRIORITY WAS IMPORTANT IN EVENT THAT THE FIELD WAS SHUT DOWN AND HAD TO DIVERT TO ALT WITH ONLY 1 GENERATOR.

Data retrieved from NASA's ASRS site as of May 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.