Connellsville, PA, USA
N46TA
CESSNA 414
The pilot, who was also a mechanic, had been troubleshooting an autopilot issue before the accident flight. He had removed and reinstalled the autopilot mode control unit in the cockpit panel and planned to complete a local maintenance test flight. The pilot initiated the flight, completed a normal run-up, and reported that nothing was abnormal with the flight controls. During takeoff and after reaching the airplane’s rotation speed, the pilot was unable to move the control wheel aft so that the elevator would move toward the airplane-nose-up direction. The pilot subsequently aborted the takeoff, but insufficient runway remained, and the airplane overran the runway and collided with trees. The fuselage and wings sustained substantial damage. Postaccident examination of airplane’s left-side cockpit avionics stack, which contained a GPS and radio unit, found that the avionics trays had sagged downward, resulting in the elevator bellcrank to become lodged within the lowest avionics tray. Further, the avionics trays were missing metal straps designed to secure the rear weight of the GPS and radio units to the structure of the airframe. The avionics tray and elevator bellcrank exhibited significant scraping and metal polishing, which indicated that rubbing contact between the sagging avionics tray and the elevator bellcrank had likely been occurring for some time before the accident flight. Neither the pilot nor the passenger (who was also a mechanic) reported observing any anomalies with the flight controls during the preflight run-up but did report that the airplane hit a dip in the runway as the airplane approached its the rotation speed. Thus, this movement likely moved the tray further downward and into the movement area of the elevator bellcrank. The Federal Aviation Administration had published advisory circular guidance advising mechanics to ensure that avionics units (including GPS and radio units) were properly secured with rear or side metal straps connected to a structural element on the aircraft. Review of maintenance records found no recent references to work involving the affected avionics or the securing of their avionics trays. The pilot had maintained the airplane for several years and signed off multiple annual inspections. During a postaccident interview, the pilot explained that he was not aware of the need to secure metal side or rear straps on avionics trays. Thus, because the pilot did not realize the need to properly secure the avionics trays to structural airplane elements, the trays eventually contacted the elevator bellcrank and precluded normal operation of the airplane’s pitch controls.
On May 2, 2022, about 1550 eastern daylight time, a Cessna 414 airplane, N46TA, was substantially damaged when it was involved in an accident at Joseph A. Hardy Connellsville Airport (VVS), Connellsville, Pennsylvania. The commercial pilot sustained minor injuries, and the passenger sustained serious injuries. The flight was operated under the provisions of Title 14 Code of Federal Regulations Part 91 as a flight test. The purpose of the flight was to perform a local maintenance test flight to evaluate the autopilot’s performance. The pilot, who was also a mechanic, reported that, before the accident flight, he had removed and then reinstalled the S-TEC autopilot mode control unit in the cockpit due to a discrepancy reported on a previous flight. The pilot stated that, after a normal taxi and “complete run-up,” he initiated the takeoff for the accident flight. When the airplane reached rotation speed, he pulled back on the flight controls with one hand, but the flight controls did not move. The pilot then pulled back on the flight controls with both hands, but the flight controls still did not move. The passenger, who was also a mechanic, reported that the pilot was unable to rotate the airplane at rotation speed. The passenger recalled that the runway surface had a dip in it and that he felt a “bump” about the time that he expected rotation to occur. The pilot aborted the takeoff and applied maximum braking. The airplane was unable to stop on the remaining runway and ran off the runway and down a ravine. The airplane subsequently collided with trees, which resulted in substantial damage to the airplane fuselage and wings. The pilot reported that there was nothing “strange” with the flight controls during the run-up. The passenger recalled that the flight controls were functional before takeoff. Postaccident examination of the cockpit panel revealed that the left avionics stack included a Garmin GNS 530 GPS and a Bendix-King KX-155 navigation/communication receiver. The avionics tray on the left side that held the KX-155 unit was found stuck within the opening area of the elevator bellcrank. When the flight controls were moved forward or aft, which also moved the elevator bellcrank forward and aft, the controls would not move. The trays in the left avionics stack were found sagging downward, and the avionics units would move downward when the front of the units were pushed by hand. Further examination revealed that the bottom rearward portion of the KX-155 avionics tray was deformed and that the tray and the bellcrank displayed significant scratching and metal polishing. When the avionics tray was removed from the bellcrank movement area, the flight controls operated with a full range of movement. The avionics trays holding the GNS 530 and KX-155 equipment were secured to the sheet metal on the front of the cockpit panel, but neither avionics tray had metal straps that secured the rear or sides of the tray to the airplane’s structure of the airplane. The KX-155 avionics tray had a metal strap on its left side that was not connected to any structure of the airframe. No other avionics trays had straps connected to the airframe structure. Figure 1 shows the cockpit, elevator bellcrank and KX-155 avionics tray. Figure 2 shows a closer view of the KX 155 avionics tray. Figure 1. Cockpit, avionics trays, and elevator bellcrank (Source: Federal Aviation Administration). Figure 2. Scratches found on the elevator bellcrank and KX-155 avionics tray (Source: Federal Aviation Administration). Note: The “FWD” label in the top left photograph shows where the face of the KX-155 unit was located. Review of Federal Aviation Administration airworthiness records revealed that the Garmin GNS 530 was first installed in the accident airplane in 2006. Review of the maintenance records starting in 2006 found no entries relating to the removal and reinstallation of the GNS 530 or the KX 155 unit. The pilot/mechanic stated that he performed numerous inspections on the accident airplane starting in 2016. The pilot/mechanic also stated that, before the accident, he “didn’t even know to look for this” on avionics trays. Federal Aviation Administration Advisory Circular 43.13-2A, Acceptable Methods, Techniques, and Practices - Aircraft Alterations, chapter 2, Radio Installations, stated in part the following: To minimize the load on a stationary instrument panel, whenever practicable, install a support between the rear (or side) surface of the radio case and a nearby structural member of the aircraft.
The pilot/mechanic’s failure to properly secure two airplane avionics units, which resulted in the trays supporting the units to sag downward and become lodged in the movement area of the elevator bellcrank during the accident takeoff.
Source: NTSB Aviation Accident Database
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