Bombardier INC CL-600-2C11 incident near Dulles, Virginia, November 20, 2024

The NTSB's narrative final · quoted from the NTSB record

On November 19, 2024, about 2020 eastern standard time (EST), GoJet Airlines flight 3375, an MHIRJ Aviation Group CL-600-2C11 (CRJ550), N501GJ, experienced pitch control stiffness and limited control column movement during the flare while landing at Dulles International Airport (KIAD), Dulles, Virginia. Despite the control issue, the airplane touched down and taxied to the gate with no further issues. The flight was operated as a Title 14 Code of Federal Regulations Part 91 repositioning flight from Richmond International Airport (KRIC), Richmond, VA to KIAD. There were no injuries to the two crew members and there was no damage to the aircraft. The airline reported that “The flight was unremarkable until the descent phase. During the descent the autopilot failed to capture a preselected altitude of 3000' MSL [mean sea level]. The pilot flying intervened at approximately 2700' MSL by disconnecting the autopilot, re-trimming the stabilizer, and re-engaging the autopilot. As the aircraft approached the KIAD airspace it was cleared to 2000' MSL. Descent was initiated on the autopilot, however the crew received the EICAS [engine indicating and crew alerting system] message "AP TRIM IS NU" [autopilot trim is nose up] at approximately 2500' MSL. The crew completed the Quick Reference Handbook (QRH) checklist and re-engaged the autopilot. The captain subsequently disengaged the autopilot when cleared for a visual approach to runway 19L.” The crew reported that the aircraft flew normally by hand until the landing flare when the captain (pilot flying) noted that the left control column felt abnormally stiff and exhibited minimal movement when pulled. After landing, maintenance personnel requested that the flight crew pull the pitch disconnect handle to help identify the source of the flight control restriction. After the disconnect, only the captain’s control column (left side) was restricted in the aircraft nose-up (control column aft) direction. A detailed maintenance inspection found that an elevator autopilot servo control cable (part number BA670-93710-13) had fractured into two sections. The lower section of the cable had backlashed around the servo mount, binding the cable between the elevator autopilot servo mount and the cable guide pins (see Figure 1 for similar example). The bound cable interfered with the rotation of the servo mount, which remained connected to the aft side of the elevator control quadrant by the intact aft cables. This condition resulted in the limited rotation of the elevator control quadrant in one direction. According to GoJet Airlines maintenance personnel, the elevator appeared to move normally in the downward direction, but in the upward direction movement was limited to about three-quarters of its full range. The broken cable was sent to the NTSB Materials Laboratory for further examination. The construction of the cable was 7x7 and made from carbon steel. The fracture occurred 14 inches from the elevator autopilot servo mount end. Examination revealed that the individual wires near the fracture were worn and exhibited features consistent with cyclic fatigue. Additional areas of wear were observed on the cable approximately 3.5 inches from the elevator control quadrant end, as well as on the other two cables (aft cables) that connected the elevator autopilot servo to the elevator control quadrant. GoJet Airlines reported that the airplane had accrued 47,106 flight hours and 37,439 flight cycles at the time of the cable failure. The cable was last inspected per MRB Task 273000-201A in May of 2016, 12,024 flight hours prior to the failure. GoJet Airlines stated that the cable had not been replaced since they acquired the airplane in October of 2019. An examination of the elevator autopilot servo and the servo mount did not reveal any anomalies that could have contributed to the cable failure. Additional Reported Cable Failures On November 24, 2024, GoJet Airlines maintenance personnel found an elevator autopilot control cable (part number BA670-93710-19) broken on a different CRJ-550 (registration number N502GJ). The pilot report that prompted maintenance to troubleshoot the autopilot system stated “Autopilot Vertical Speed Mode not actuating flight controls. Will not climb or descend.” This failure resulted in the cable backlashing around the servo mount but did not cause any reported restrictions to manual elevator control (see Figure 1). Laboratory analysis revealed that the cable failed approximately 14.75 inches from the servo mount end. Most of the wires exhibited flat fracture surfaces, and individual wires showed wear adjacent to the fracture locations. The airplane had accrued 48,386 flight hours and 38,137 flight cycles at the time of the cable failure. The cable was last inspected per MRB Task 273000-201A in December 2020, 5,579 flight hours before the failure occurred. GoJet Airlines stated that the cable had not been replaced since they acquired the airplane in December of 2019. Figure 1. Cable backlashed in elevator autopilot servo mount from the N502GJ event. (Courtesy of GoJet Airlines) On August 3, 2025, GoJet Airlines maintenance found elevator autopilot control cable (part number BA670-93710-13) broken on another CRJ-550 (registration number N506GJ). The crew reported that they felt a pitch restriction in the aircraft nose up direction when pulling back on the column during flare, but the airplane landed without incident. The failed cable and the adjacent cable were found backlashed around the servo mount, binding the cables between the elevator autopilot servo mount and the cable guide pins. The break occurred approximately 14 inches from the servo mount end. The fracture surface was similar to the other failed cables in that many of the wires had flat fracture surfaces and individual wires exhibited wear adjacent to the fracture surfaces. This failure region also had a relatively high number of wires (when compared to the other examples examined by the NTSB laboratory) that demonstrated necking and non-flat fracture surfaces consistent with overload. In addition, the fracture area contained some rust, but not as much as the other examples. The airplane had accrued 46,833 flight hours and 37,217 flight cycles at the time of the cable failure. The cable was last inspected per MRB Task 273000-201A in March of 2025, 656 flight hours before the failure occurred. GoJet Airlines stated they did not replace the cable since they acquired the airplane in October of 2019. The NTSB has also opened an investigation into a reported elevator autopilot control cable failure event that occurred on a different airline in November of 2025 (NTSB Investigation Number ENG26LA011). This investigation is ongoing as of the time of this report release. Historical Events Canadian Service Difficulty Report 20100813016 was filed in July of 2010 by a different operator for a CRJ-700. The crew reported an “AP Pitch Trim” message during the flight. The report stated: “At landing, at altitude 10ft, with engines at idle power, when crew ordered nose up to compensate the aircraft deceleration, as high effort to be exerted on the elevator control, nevertheless the touch down was normal. During taxiing, the elevator control is not found fully operative, which jammed at the middle range when ordered nose up.” According to MHIRJ, the cable (available information did not specify the cable part number) was found broken at its end fitting near the elevator control quadrant with the side attached to the servo mount wrapped around the mount in a way that caused the mount to bind. The root cause of the failure was suspected to be the incorrect installation of the cable. MHIRJ was also aware of a Technical Occurrence Notification reported for airplane serial number 10083 (a CRJ-700) with an occurrence date of November 1, 2017. The report stated: ”Pilot reported that during final approach a control column strange movement occurred and after that the aircraft started to descend [below] Glide Slope path and pilot was also capable to move the control column in pitch still with autopilot engaged.” While maintenance was troubleshooting the autopilot defect, it was observed that the left-hand elevator was not able to fully deflect to the up position, and the left control column was difficult to bring all the way back (column movement was limited to about three-quarters aft travel and described as having a spring effect). The elevator servo cable (available information did not specify the cable part number) was found broken with “a lot” of corrosion. The report further stated that it was “a jammed cable on the capstan that most likely caused the elevator not reaching it[s] full up position.” Corrective Actions GoJet airlines submitted Service Difficulty Reports for the N501GJ, N502GJ, and N506GJ events. MHIRJ released service bulletins SB 670BA-27-078 and SB 601R-27-167, both dated 01 October 2025, to provide instruction to replace the affected cables on CRJ 200/550/700/900/1000 based on accrued flight hours of the cables. Transport Canada released Airworthiness Directive number CF-2025-63 with effective date of 1 December 2025 to mandate compliance with the MHIRJ service bulletins. The Federal Aviation Administration released Airworthiness Directive number 2026-02-03 with effective date of 5 February 2026 to require replacing the elevator autopilot control cables on affected airplanes.

The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.