Narrative:

Aircraft is a cessna 172. We were taxiing at iad out to runway 30. I lost my right brake just short of the W2 intersection. I told ground that I lost my right brake and in an attempt to stop the airplane could only make left turns. The ground controller understood and permitted a left 360 degree turn which put me at the W2 intersection of runway 30. At that point, my brakes failed totally and my aircraft slowly creeped forward due to the torque of the engine. I then unknowingly passed the hold short line for runway 30 by about 20 ft. 2 air carrier planes departed and at that point I just could not hold the plane still. Dulles tower cleared me for takeoff. I rolled out on the runway and then decided to abort and go back and look at the brakes. Ground then cleared me to taxi with 'total brake failure' back to the FBO. On the way back, the brakes regained function. Upon inspection, there seemed to be no problems with the brake system. Nobody queried my position at W2 intersection of runway 30. My plane was in no danger and neither was any other departing traffic. My only concern was that I did pass the hold short by approximately 20 ft and then rested. When my plane began to roll again, I was cleared onto the runway. The hold short line at the W2 intersection of runway 30 is very vague. The point is worn and very light. This situation may have been prevented if the lines were more distinct.

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Original NASA ASRS Text

Title: HOLDING SHORT OF RWY FOR TKOF PLT ALLEGEDLY LOST BRAKES AND CROSSED HOLD LINE. RETURNED TO RAMP AND FOUND NO PROB WITH BRAKES.

Narrative: ACFT IS A CESSNA 172. WE WERE TAXIING AT IAD OUT TO RWY 30. I LOST MY R BRAKE JUST SHORT OF THE W2 INTXN. I TOLD GND THAT I LOST MY R BRAKE AND IN AN ATTEMPT TO STOP THE AIRPLANE COULD ONLY MAKE L TURNS. THE GND CTLR UNDERSTOOD AND PERMITTED A L 360 DEG TURN WHICH PUT ME AT THE W2 INTXN OF RWY 30. AT THAT POINT, MY BRAKES FAILED TOTALLY AND MY ACFT SLOWLY CREEPED FORWARD DUE TO THE TORQUE OF THE ENG. I THEN UNKNOWINGLY PASSED THE HOLD SHORT LINE FOR RWY 30 BY ABOUT 20 FT. 2 ACR PLANES DEPARTED AND AT THAT POINT I JUST COULD NOT HOLD THE PLANE STILL. DULLES TWR CLRED ME FOR TKOF. I ROLLED OUT ON THE RWY AND THEN DECIDED TO ABORT AND GO BACK AND LOOK AT THE BRAKES. GND THEN CLRED ME TO TAXI WITH 'TOTAL BRAKE FAILURE' BACK TO THE FBO. ON THE WAY BACK, THE BRAKES REGAINED FUNCTION. UPON INSPECTION, THERE SEEMED TO BE NO PROBS WITH THE BRAKE SYS. NOBODY QUERIED MY POS AT W2 INTXN OF RWY 30. MY PLANE WAS IN NO DANGER AND NEITHER WAS ANY OTHER DEPARTING TFC. MY ONLY CONCERN WAS THAT I DID PASS THE HOLD SHORT BY APPROX 20 FT AND THEN RESTED. WHEN MY PLANE BEGAN TO ROLL AGAIN, I WAS CLRED ONTO THE RWY. THE HOLD SHORT LINE AT THE W2 INTXN OF RWY 30 IS VERY VAGUE. THE POINT IS WORN AND VERY LIGHT. THIS SIT MAY HAVE BEEN PREVENTED IF THE LINES WERE MORE DISTINCT.

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.