Pilot Debrief

BENNETT MIDJET MUSTANG I near Ramona, CA — 2011-04-10

Final reportWPR11LA205
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Date
2011-04-10
Location
Ramona, CA, USA
Airport
RNM
Aircraft
BENNETT MIDJET MUSTANG I
Registration
N611JB
Category
Airplane
Highest injury
Minor
Fatalities
0
Phase of flight
Initial climb

Probable cause

The pilot's inability to maintain directional control during the landing roll due to the overload separation of the left brake master cylinder from the left rudder pedal assembly.

NTSB narrative

The pilot reported that while conducting a series of touch-and-go takeoffs and landings in a tailwheel-equipped airplane, he heard a loud snap sound during his third takeoff followed by the upper left rudder pedal collapsing. The pilot verified that he had rudder control and noticed that the upper left rudder pedal seemed displaced forward of its normal position. He further noticed that the left rudder pedal was binding at various times, but overall was operational, and thus suspected that the left brake master cylinder had disconnected from the rudder pedal. The pilot said that every time he applied left rudder during the landing the airplane veered to the left as if left brake was being applied. Despite his control inputs, the airplane exited the left side of the runway and nosed over within the soft muddy terrain, which resulted in substantial damage to the fuselage and both wings. Postaccident examination of the airplane revealed that the left brake master cylinder was separated from the left rudder pedal at the rudder attach point. Examination of the left rudder pedal and master cylinder revealed that the left rudder pedal was fractured at the lug where it attached to the upper end of the brake master cylinder. The fracture surface was consistent with an overstress fracture. The fracture surface was examined by an NTSB metallurgist using a scanning electron microscope and no evidence of fatigue or other progressive crack growth was observed. The lower surface of the brake master cylinder attachment lug on the left rudder pedal had an impression corresponding to contact with the lower end of the clevis of the left master brake cylinder attachment fitting. A similar impression was observed on the lower surface of the brake master cylinder attachment lug on the right rudder pedal. Deformation consistent with contacting the lower surface of the rudder pedal lugs was observed at the base of the clevis in the upper attachment fittings of both the left and right brake master cylinders.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot could have inspected the rudder pedal before the flight.

NTSB coding

Evidence available

  • Photos
  • 4 docket documents
View NTSB final reportView NTSB docket

Docket documents4

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