N811PBBeech 58 · 1972

On October 29, 2024, about 1426 central daylight time, a Beech 58 airplane, N811PB, was destroyed when it was involved in an accident near Arlberg, Arkansas. The pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight.

Earlier on the morning of the accident, the pilot flew the airplane from Roscoe Turner Airport (CRX), Corinth, Mississippi, to Drake Field Airport (FYV), Fayetteville, Arkansas, to have the airplane inspected at an avionics shop to troubleshoot an intermittent autopilot issue where the airplane exhibited an occasional slow pitch oscillation with the autopilot engaged and a 100 ft out-of-trim condition when the autopilot was subsequently disengaged. The avionics technician’s initial recommendation was to examine the autopilot pitch servo and pitch trim servo.

The avionics technician disassembled the rear baggage compartment to gain access to the aft fuselage where the autopilot pitch servo and pitch trim servo were installed. A visual inspection revealed that there were two loose bolts securing the autopilot pitch servo capstan assembly to the servo mount bracket. Additionally, the elevator pitch control bridle cable appeared to be overtightened. The autopilot pitch servo was removed for bench testing and was not reinstalled before the accident flight.

Further examination revealed excessive grease on the pitch trim cable routed through the pitch trim servo idler pulley. The avionics technician stated that while he rubbed a shop towel along the pitch trim cable it snagged a frayed portion of the cable. The frayed pitch trim cable was, looking forward, the far-left-cable routed through the pitch trim servo capstan. According to the Beech 58 Airplane Maintenance Manual, the frayed cable was identified as the “nose up” pitch trim cable.

The avionics technician told the pilot that the pitch trim cable was frayed and asked for the pilot’s mobile phone so he could take a couple photos of the frayed pitch cable for the pilot to review with his aviation mechanic, as shown in Figure 1. The avionics technician was concerned that the frayed pitch trim cable could fail during flight and told the pilot that the pitch trim cable required replacement.

Figure 1. Photo of frayed pitch trim cable before accident flight.

The pilot then called his aviation mechanic and texted him the photos of the frayed pitch trim cable. After discussing the frayed pitch trim cable, the pilot indicated that he wanted to his aviation mechanic to replace the frayed cable and that he would fly the airplane without any repairs being completed. According to the avionics technician, the pilot did not appear to be concerned about the frayed pitch trim cable. Specifically, the pilot reportedly told the avionics technician that the frayed cable was “not that bad” and that he had “seen worse cables”. The pilot also reportedly told the secretary that the avionics technician was “overreacting” to the frayed pitch trim cable situation.

The pilot told the avionics technician multiple times that he needed to depart and return to his homebase in Mississippi that afternoon. Worried that the frayed pitch trim cable would fail during flight, the avionics technician decided to install a single length of 0.041-inch safety wire to “bridge” the frayed section of the pitch trim cable.

According to the avionics technician, before the installation of the safety wire, the pitch trim system was moved to a “neutral” position because he believed it would be the “safest position” and that the takeoffs are made in the neutral pitch trim position. However, the frayed pitch trim cable was “catching” on the capstan while the pilot moved the cockpit pitch trim control wheel from a full-nose-down position toward the neutral pitch trim position. The avionics technician wound the frayed wires around pitch trim cable and applied “super glue” to affix/secure the frayed wires. The pitch trim was then positioned to neutral, as determined by the cockpit pitch trim indicator positioned at “zero” and both (left/right) pitch trim tabs were aligned with their respective elevator (the trailing edges of the trim tabs and elevators were aligned).

The avionics technician stated that after he confirmed the pitch trim was in the neutral position he installed the single strand of 0.041-inch safety wire to the frayed pitch trim cable. He made the first connection at the “rear turnbuckle” and then routed the safety wire forward, under the metal pully guard at the pitch trim servo capstan, and then terminated the safety wire through two turnbuckles located forward of the pitch trim servo. The avionics technician noted that he was unable to get the safety wire significantly tight during its installation.

When interviewed after the accident, the avionics technician explained that the installation of the safety wire was not meant to disable the pitch trim system, but rather to keep the frayed pitch trim cable tethered if it failed during flight. The avionics technician acknowledged that the installation of safety wire was “not standard protocol” but, because the pilot intended to fly the airplane without replacing the frayed pitch trim cable, it was the only way he knew to “make it safe” if the frayed pitch trim cable failed during flight. Additionally, the autopilot and pitch trim circuit breakers were pulled-and-collared, and the avionics technician told the pilot not to use the manual pitch trim if he intended to fly airplane with the frayed pitch trim cable.

The avionics technician stated that he installed the safety wire by himself and did not receive any assistance from the pilot. When asked how he identified which pitch trim cable at the rear of the aft fuselage to make his first safety wire attachment, the avionics technician answered that the pitch trim cable was “easy to follow” from the frayed section rearward.

After the safety wire was installed, with the avionics technician still in the aft fuselage, the pilot moved the elevator and rudder controls through their full range-of-travel to confirm that there were no anomalies or binding of the control cables. The avionics technician stated that he intentionally did not test the pitch trim because he was “afraid to move it and break the frayed cable”.

The avionics technician then completed an additional preflight check, completed from outside the airplane, that did not identify any binding while the elevators and rudder were moved through their full travel by hand, and that the pitch trim tabs remained aligned with their respective elevator.

The avionics technician stated that he was the only employee that performed work on the airplane and that he did not request another technician to check his work after the safety wire was installed. The avionics technician stated that he closed the workorder without the frayed pitch trim cable being replaced. The avionics technician noted that he had the authority to close the workorder without another employee checking his work. Additionally, he and the pilot did not discuss if a Federal Aviation Administration (FAA) issued ferry permit was required for the flight.

The avionics technician stated that he was in the process of closing out the workorder and writing up the logbook entries when the pilot departed the facility on the accident flight. He stated that the pilot was eager to depart and did not remain at the facility until the workorder and logbook paperwork was completed.

According to FAA Automatic Dependent Surveillance - Broadcast (ADS-B) data, at 1355, the airplane departed from runway 16 at FYV. After takeoff, the airplane made a climbing left turn toward east and then established a direct course toward CRX. As the flight continued, the airplane climbed to a cruise altitude of about 9,000 ft mean sea level (msl), as shown in Figure 2.

Between 1421:42 and 1421:50, there was an open-mic transmission that consisted of audible breathing. At 1421:51, the controller asked the pilot if he could hear her transmission. The pilot replied, “loud and clear one papa bravo.”

At 1422:03, the pilot told the air traffic controller “we’re having trim issues” and requested the closest airport with a 5,000 ft long runway. The controller replied that that Batesville Regional Airport (BVX), Batesville, Arkansas was the closest airport with a 5,000 ft long runway. At 1422:51, the pilot requested radar vectors to BVX. The controller told the pilot to fly a 090° heading.

Between 1423:16 and 1423:21, there was another open-mic transmission that consisted of audible breathing. At 1423:48, the controller told the pilot that BVX was about 45 nm ahead of the airplane’s current position. The pilot did not reply to the transmission.

At 1424:08, the controller asked the pilot if he could hear her transmissions. At 1424:10, the pilot replied, “loud and clear.” The controller then told the pilot that, if the airplane continued to descend, they might need to relay communications through another airplane that was operating in the area. At 1424:25, the pilot replied, "ah, that's not going to be possible cause we are using all of our energy to overcome the trim."

Figure 2. Plot of airplane altitude, ground speed, true airspeed, calibrated airspeed, and vertical speed.

At 1424:31, the controller told the pilot that Clinton Municipal Airport (CCA), Clinton, Arkansas, had a 4,000 ft long runway and was south of the airplane’s current position. The controller also reiterated that BVX was about 45 nm away. At 1424:45, the pilot replied, “roger, we’ll probably need the five thousand feet to control the airplane, declaring an emergency.” The pilot’s final recorded transmission was at 1424:56 when he told the controller that there was “one soul on board, four hours of fuel.”

At 1425:33, the controller suggested that the pilot should land at CCA, which was at pilot’s 3 o’clock and 7 nm. The controller then asked another pilot flying in the area to relay her communications to the accident pilot. There was no recorded response from the pilot.

At 14:26:09, the final ADS-B track data point was recorded about 0.18 nm west-northwest of the accident site. At that time, the airplane was at 1,575 ft msl (170 ft above ground level), 203 knots calibrated airspeed, and descending about 1,800 feet per minute. The airplane had a 103° true ground track, 6.7° right-wing-down roll, and -4.7° flight path angle. The airplane subsequently descended into trees.

A survey of the wreckage debris path confirmed that the airplane descended wings level into the trees. The distance between the initial tree strike and the main wreckage was about 245 ft. The airplane fragmented into several portions during the descent through the trees. All major structural components, flight controls, engines, and propellers were located along the wreckage debris path. The cockpit flight controls were destroyed during impact. Flight control cable continuity was established between the rudder and elevator bellcranks to the cockpit. Flight control cable continuity to the ailerons was partially established from the cockpit area to the wing roots where there was evidence of overload separations. A measurement of the left flap actuator was consistent with a flap extension between 0° and 5°. The right flap actuator was not located. The aileron trim actuator was not identified in the highly fragmented wing. The rudder trim actuator was located but its position was determined as unreliable due to impact-related damage. Consistent with the avionics technician’s statement, the autopilot and pitch trim circuit breakers were found pulled-and-collared at the accident site.

The pitch trim cables were observed with three separations: one aft of the pitch trim servo and two at the horizontal stabilizer forward spar. The left pitch trim actuator position was consistent with 10° to 15° nose down, and the right pitch actuator position was consistent with 10° nose up.

The nose-up pitch trim cable was found with a single length of safety wire attached to the turnbuckles located forward of the pitch trim servo, consistent with the avionics technician’s description. The safety wire was routed aft and attached to the nose-down pitch trim cable at its rear turnbuckles, as depicted in Figure 3. Notably, the safety wire was attached to both the nose-up and nose-down pitch trim cables, inconsistent with the avionics technician’s explanation that he attached the safety wire to “bridge” the frayed area of the nose-up pitch trim cable. Based on the postaccident examination, the installed safety wire would have allowed the pitch trim to be moved between full-nose-down and the point where the safety wire became sufficiently taught to prevent further cable movement in the nose-up direction. Based on the avionics technician’s statement, the safety wire would have been taught near the neutral pitch trim position. The observed safety wire routing at the accident site would have precluded nose-up trim positions. Segments of the pitch trim cable circuit were retained for additional examination at the National Transportation Safety Board Materials Laboratory.

Figure 3. Functional schematic of pitch trim cables.