Weyers Cave, VA, USA
N7242F
PIPER PA-28-140
The pilot reported that, while landing, less than 100 ft above ground level, he felt that the approach was unstable and decided to go around. He smoothly applied full engine power, but the airplane did not gain any altitude and started banking hard to the left. He stated that the airplane was to the left of the runway and that he was applying right aileron and right rudder to level the wings with no effect. The airplane subsequently impacted a fence and trees. The pilot was seriously injured, his passenger received minor injuries, and the airplane was substantially damaged. Examination of the airplane revealed that the rudder bar arm and rudder pedal tube, which were part of the rudder control assembly, had separated near a weld, which displayed a crack where extensive corrosion was visible on the fracture surface. Examination under magnification revealed that the fracture of the rudder arm began with an unknown overload event, and crack growth had occurred slowly. As the crack developed, the fracture surfaces fretted against each other until the crack grew enough to cause the left and right fracture surfaces at the base of the weld to the rudder tube to fail as a hinge point, causing a cup-and-cone failure with fresh substrate at the base of the fracture surface. The airplane had accrued about 11,406 hours as of its most recent 100-hour inspection, which was completed about 3 months before the accident. A review of manufacturer’s published guidance revealed multiple documents that included inspection requirements for the rudder pedals, rudder bar, and rudder bar support assembly, which were readily accessible by maintenance personnel for visual inspection. Review of the airplane maintenance records did not reveal any entries that referenced any of the published inspection requirements for the rudder pedals, rudder bar, and rudder bar support assembly. Even without rudder control, the airplane likely remained controllable; however, given the 6-knot right crosswind that existed at the time of the accident, and the airplane’s proximity to the ground when the failure occurred, it is likely that the failure of the rudder control assembly resulted in the pilot’s loss of control.
On April 12, 2021, about 1920 eastern daylight time, a Piper PA-28-140 airplane, N7242F, was substantially damaged when it was involved in an accident in Weyers Cave, Virginia. The pilot was seriously injured, and the passenger received minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that, on the evening of the accident, he planned to fly to Shenandoah Valley Regional Airport (SHD), Weyers Cave, Virginia, perform a touch-and-go landing, then return to the area of the departure airport, do maneuvers until dark, and then land. Before departing, he conducted his normal preflight inspection and filled both fuel tanks. The flight was uneventful, and he entered the traffic pattern for runway 23 at SHD. Upon turning onto the final leg of the traffic pattern, he opted to land with only two notches of flaps because of an 8-knot crosswind. He reported that, around 100 ft above the runway at an airspeed about 90 mph, he decided to go around, since the airplane was fast and it felt like the approach was unstable. He smoothly applied full power, but the airplane did not gain any altitude, and started banking hard to the left. By this time, the airplane was about 50 ft above ground level, left of the runway, and the pilot was applying right aileron and right rudder in an attempt to level the wings. He had no further memory of the accident sequence. The engine remained attached to the engine mounts and firewall. The propeller remained attached to the engine with a slight bend to the crankshaft flange face. Except for the alternator, the accessories and base engine appeared to be undamaged condition. The Nos. 1 and 3 cylinders had markings consistent with chrome barrels, the Nos. 2 and 4 cylinders had markings consistent with nitride barrels. The propeller was rotated by hand and thumb compression and suction was established on all four cylinders via the top spark plug holes. Valve train movement was observed, and continuity was confirmed throughout the engine. The exhaust stacks for all four cylinders displayed crush damage from the impact forces. The exhaust stack studs on cylinder Nos. 2 and 4 had pulled slightly away during the impact sequence. No evidence of any preimpact malfunction or failure of the engine was discovered. Flight control continuity was established from the control wheels in the cockpit to the breaks in the system, and from the breaks in the system to the left and right ailerons and the stabilator. Flight control continuity could not be established from the rudder pedals to the rudder, and during examination of the rudder pedal assembly, it was discovered that the rudder bar arm (Part No. 63448-000) and rudder pedal tube (Part No. 65165-053), which were part of the rudder control assembly (Part No.66661-000), had separated. Visual examination of the separated rudder bar arm and rudder pedal tube revealed that they had separated near a weld, which displayed a crack where extensive corrosion was visible on the fracture surface. Examination of the fractured surface under magnification revealed a peak in the fracture surface which was indicative of where an initial overload sometime in the past had occurred that caused a crack to begin. To the left of the peak along the fracture surface, corrosion products could be seen all along the fracture surface. This indicated that the crack had been open for a while and the fracture surface was allowed to react with oxygen to create iron oxide and other corrosion products as well as capture debris. To the right of the peak along the fracture surface, pockets of corrosion as well as fresh substrate were visible, which was indicative of gnashing of the right fracture surface against the opposite surface through cyclic movements (such as the actuation of the control cable) which would continuously remove corrosion products and expose fresh substrate. Down along either side of the arm, two fresh substrate areas could also be observed. The right fracture surface at the base of the weld also exhibited porosity which was indicative of a cup-and-cone failure (tensile failure in a ductile material). Voids or contamination in the weld were also visible. Review of Federal Aviation Administration (FAA) and airplane maintenance records indicated that the airplane had been manufactured 53 years prior to the accident and had accrued about 11,406 hours as of its last 100-Hour inspection, which was completed on January 19, 2021. A review of Piper Aircraft published guidance revealed multiple documents that included inspection requirements for the rudder pedals, rudder bar, and rudder bar support assembly, which included: The Piper Aircraft Corporation Inspection Report Form for the Cherokee Series Airplanes (PA-28-140/150/160/180/235), which at intervals of 100-hours required under Item No. 8 to “Inspect condition and operation of rudder pedals and rudder bar assembly (See Note 28).” Note 28 stated, “In airplanes with a rudder pedal and bar assembly or with a rudder bar support assembly, that has1,200 hours or more time-in-service each 100 hours perform Rudder Pedal and Bar Assembly Inspection and/or Rudder Bar Support Assembly inspection on page III-90. As appropriate.” The Piper Cherokee Service Manual, Section III-Inspection (Page III-90), required “In airplanes with rudder pedal and bar assembly or, for fixed gear airplanes only, with a rudder bar support assembly, that has 1,200 hours or more time-in-service each 100 hours inspect the rudder pedal and bar assembly and/or the rudder bar support assembly for cracks as follows:” It then goes on to say in part, to use a 10X magnifier, a mirror, and a suitable light source to visually inspect all welds, and that any cracked components must be replaced before next flight. Additionally, it also stated, “If no cracks are detected (or upon appropriate replacement of cracked or damaged parts), make proper logbook entry documenting completion of this inspection.” Piper Service Letter (SL) No.671(Rudder Bar Assembly Inspection and Modification), dated October 5, 1973, was issued to bring to the attention of field maintenance facilities the necessity of a visual inspection of the rudder bar assembly to detect evidence of cracks, and to provide material and instructions to fabricate and install reinforcement doublers to the affected area. Initial inspection was to be accomplished at the next regularly scheduled inspection interval, and to be repeated within each subsequent 100 hours of operation until the modification (the addition of doublers was accomplished). Piper Service Bulletin (SB) No. 1242 (Rudder Pedal Assembly Inspection), dated January 30, 2015, was issued as a review of the service history on the affected airplanes revealed that, over time, cracks may develop in specific locations on the pedal and bar assembly and the rudder bar support assembly. This service bulletin provided a schedule and instructions for the inspection of these critical components for cracks, and for modification or replacement, on condition. SB1242 superseded SL 671 in its entirety, and airplanes that were in compliance with SL 671 were still required to comply with SB1242. Piper Service Bulletin (SB) 1242A (Rudder Pedal Assembly Inspection), dated May 12, 2020, added additional inspection locations, and SB 1242A superseded SB 1242 and SL 671 in their entirety. Airplanes that have previously complied with SL 671 were still required to comply with SB 1242A. Airplanes that had previously complied with SB 1242 were in compliance with SB 1242A until the next inspection interval was reached. Review of the rudder bar assembly drawing revealed that the rudder control assembly was readily accessible by maintenance personnel for visual inspection. Further review of the airplane maintenance records also did not reveal any entries that referenced any of the published inspection requirements for the rudder pedals, rudder bar, and rudder bar support assembly. According to FAA and pilot records, the pilot held a private pilot certificate with ratings for airplane single-engine land, and instrument airplane. His most recent application for a FAA third-class medical certificate was dated June 22, 2020. The pilot reported about 138 total hours of flight experience, of which 84 hours were in the accident airplane make and model. Review of weather conditions that existed around the time of the accident indicated that the airplane while on final approach to landing, would have been subjected to an approximate 2 knot headwind, and a crosswind from the right of approximately 6 knots. Review of the flight characteristics of the PA-28-140 indicated that, even without rudder, the vertical tail would provide enough directional control to counter the “left-turning tendencies” during take-off or go-around, though the rolling moment due to the sideslip would have tried to roll the airplane left without any right rudder input. Roll could be compensated by adding right aileron inputs.
Maintenance personnel’s inadequate inspection of the rudder control system, which resulted in failure of the rudder control assembly and the pilot’s loss of control during a go-around.
Source: NTSB Aviation Accident Database
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