Narrative:

At 6000 ft on assigned heading 180 degrees, GPWS sounded with 'terrain, terrain, climb, climb.' went maximum power and took off altitude and pitched to about 20 degrees (250 KTS). GPWS sounded several more times then silenced. I stopped the climb at 7300 ft. First officer told ATC who said come back down to 6000 ft when able. Although I 'knew' there weren't 6000 ft mountains, I thought maybe I had misread the altimeter or maybe altimeter system had failed. Thinking back, radar altimeter had 'fluttered' up to plus or minus 1000 ft prior (don't know how prior). This occurred about over cia buildings. If they radiate electromagnetic 'stuff' (I'm a business major, not engineering!) that affects our aircraft such that we have to immediately leave assigned altitudes, especially in as congested an area as the dc area, we could certainly have midair collisions (not to mention ATC controllers and pilots with more gray or missing hair). We did tell the controller as soon as possible but with frequency congestion, etc, it took way too long for him to do any controling. I assume the cia would deny everything but just the question to them may make them check internally.

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Original NASA ASRS Text

Title: FALSE GPWS WARNING CAUSES MLG TO CLB FROM 6000 FT TO 7300 FT IN IMC.

Narrative: AT 6000 FT ON ASSIGNED HDG 180 DEGS, GPWS SOUNDED WITH 'TERRAIN, TERRAIN, CLB, CLB.' WENT MAX PWR AND TOOK OFF ALT AND PITCHED TO ABOUT 20 DEGS (250 KTS). GPWS SOUNDED SEVERAL MORE TIMES THEN SILENCED. I STOPPED THE CLB AT 7300 FT. FO TOLD ATC WHO SAID COME BACK DOWN TO 6000 FT WHEN ABLE. ALTHOUGH I 'KNEW' THERE WEREN'T 6000 FT MOUNTAINS, I THOUGHT MAYBE I HAD MISREAD THE ALTIMETER OR MAYBE ALTIMETER SYS HAD FAILED. THINKING BACK, RADAR ALTIMETER HAD 'FLUTTERED' UP TO PLUS OR MINUS 1000 FT PRIOR (DON'T KNOW HOW PRIOR). THIS OCCURRED ABOUT OVER CIA BUILDINGS. IF THEY RADIATE ELECTROMAGNETIC 'STUFF' (I'M A BUSINESS MAJOR, NOT ENGINEERING!) THAT AFFECTS OUR ACFT SUCH THAT WE HAVE TO IMMEDIATELY LEAVE ASSIGNED ALTS, ESPECIALLY IN AS CONGESTED AN AREA AS THE DC AREA, WE COULD CERTAINLY HAVE MIDAIR COLLISIONS (NOT TO MENTION ATC CTLRS AND PLTS WITH MORE GRAY OR MISSING HAIR). WE DID TELL THE CTLR ASAP BUT WITH FREQ CONGESTION, ETC, IT TOOK WAY TOO LONG FOR HIM TO DO ANY CTLING. I ASSUME THE CIA WOULD DENY EVERYTHING BUT JUST THE QUESTION TO THEM MAY MAKE THEM CHK INTERNALLY.

Data retrieved from NASA's ASRS site as of July 2007 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.