Narrative:

I was taxiing [a] piper archer to the run-up area. The flight was being conducted as an introductory flight for a brand new customer. The pre-flight; startup; and taxi; up until the run-up pad; were normal. A brake test was accomplished during the first part of the taxi and both brakes were used gently during the taxi. Upon reaching the run-up pad; a right turn was made to enter it; followed by a gentle left turn (I did not use any braking for this left turn). As the aircraft reached the desired run-up spot on the southeast side of the pad; I applied pressure to both brakes. The aircraft veered sharply to the right heading off of the pad to the south. I immediately released the right brake and applied full left nose wheel steering as well as continued left brake in order to straighten the aircraft. The left brake did not react and the aircraft proceeded to make a gentle left turn. Because the left brake did not actuate; the aircraft continued off the pad into the grass. I did not want to use the right brake for fear of striking the sign with the propeller; rather than the right wing. The fiberglass right wingtip impacted the sign off of the southeast side of the pad; knocking it over. Damage to the aircraft appears to be a cosmetic paint scrape. I immediately shut down the engine and contacted the ground frequency in order to inform them of what happened. Post shut down inspection revealed that the left brake pedal had gone 'soft' with no pressure. There were no injuries and damage to aircraft and property was minimal.

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Original NASA ASRS Text

Title: PA-28 instructor pilot reported striking a sign with a wingtip during taxi when directional control was lost due to a malfunctioning left brake.

Narrative: I was taxiing [a] Piper Archer to the run-up area. The flight was being conducted as an introductory flight for a brand new customer. The pre-flight; startup; and taxi; up until the run-up pad; were normal. A brake test was accomplished during the first part of the taxi and both brakes were used gently during the taxi. Upon reaching the run-up pad; a right turn was made to enter it; followed by a gentle left turn (I did not use any braking for this left turn). As the aircraft reached the desired run-up spot on the southeast side of the pad; I applied pressure to both brakes. The aircraft veered sharply to the right heading off of the pad to the south. I immediately released the right brake and applied full left nose wheel steering as well as continued left brake in order to straighten the aircraft. The left brake did not react and the aircraft proceeded to make a gentle left turn. Because the left brake did not actuate; the aircraft continued off the pad into the grass. I did not want to use the right brake for fear of striking the sign with the propeller; rather than the right wing. The fiberglass right wingtip impacted the sign off of the southeast side of the pad; knocking it over. Damage to the aircraft appears to be a cosmetic paint scrape. I immediately shut down the engine and contacted the ground frequency in order to inform them of what happened. Post shut down inspection revealed that the left brake pedal had gone 'soft' with no pressure. There were no injuries and damage to aircraft and property was minimal.

Data retrieved from NASA's ASRS site 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.