Prior to start-up, the student pilot performed a preflight inspection of the Cessna 172 while the flight instructor reviewed the airplane maintenance discrepancy sheet.
The flight instructor noted that the airplane had recently been written up for inconsistent right brake pressure. Maintenance personnel resolved the discrepancy by tightening the pilot side brake pedal and returned the airplane to service.
Everything appeared visually normal during the subsequent preflight inspection, and the student and CFI performed an engine run-up with no braking problems noted.
During the taxi to the runway at the airport in New Smyrna Beach, Florida, while attempting to negotiate a turn, the right brake was not effective despite both the student and the instructor applying brake pedal pressure. The airplane went off the taxiway and hit a tree, resulting in substantial damage to the horizontal stabilizer.
A review of photographs taken by an FAA inspector of the disassembled braking system components revealed that the right brake master cylinder o-ring appeared worn and possibly had a flat spot. It is possible that the wear/flat-spot of the o-ring could have allowed fluid to bypass it, which would have resulted in the inconsistent brake operation described by the pilots.
Probable Cause: A failure of the right brake during taxi, which resulted in a taxiway excursion and collision with a tree.
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This January 2024 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
……Strange?
I can understand the dilemma when taxiing a plane like my RV-7A with differential braking only, but with a steerable nose gear, I’m kinda baffled how you could do this much damage.
Lock-o-seals! Used to keep a baby jar full of them.
Cannot help wondering exactly what was “tightened” on the R/H brake pedal.
Exactly!
Tightening the brake pedals seems to me like a hail mary shot-in-the-dark Band Aid ‘repair’ to get the plane out of the shop and the bill paid pronto. If one of my cars had a hard pull to the left or right, I’d suspect something amiss in the wheel. But I wouldn’t be stupid enough to just tighten the brake pedal. Another shop malpractice case.
Regards/J
I suggest stop taxing around at near Vr speeds.