NTSB · Safety Recommendation
Safety Recommendation A-20-004
Recommendation
TO THE CIVIL AVIATION AGENCY OF BRAZIL: Once Embraer revises design and maintenance documentation for Embraer EMB-170/175/190/195/Lineage 1000 series airplanes as requested in Safety Recommendation A-20-3, require operators of these airplanes to incorporate these changes.
Safety Issue and Context
On November 6, 2019, the flight crew of Republic Airways flight 4439, an Embraer EMB-175, declared an emergency shortly after takeoff from ATL with six passengers on board, reporting a pitch trim-related flight control issue and difficulty controlling the airplane. The captain (who was in the left seat and the pilot flying) later reported recognizing the flight control issue after a failed attempt to engage the autopilot about 2,200 ft mean sea level.
The captain stated that he conducted the single memory item on Republic’s Pitch Trim Runaway checklist to push and hold the autopilot/trim disconnect button on his side (figure 1 shows Republic’s quick reference handbook [QRH] checklist for a pitch trim runaway).1 The captain then asked the first officer to push and hold the right-side autopilot/trim disconnect button. The flight crewmembers reported that they did not notice any change in the pitch condition and continued to have difficulty holding the nose down.
The captain and first officer later reported that they both needed to use both hands to counter the airplane’s nose-up pitch motion and that doing so involved such effort that neither felt that they could reach for the QRH to troubleshoot the problem. Ultimately, the flight crew was able to trim the airplane with the first officer’s trim switch, return to ATL, and land the airplane safely about 15 minutes after declaring the emergency.
Review of data from the incident flight revealed that the airplane was in a mistrim condition for a portion of the flight. While this incident is still under investigation, three areas of concern have been identified: wire chafing, application of Embraer service bulletins (SB) related to the pitch trim switch, and potential limitations in checklist memory item(s) to help Embraer pilots address unintended operation of the pitch trim system.
Response History
February 24, 2025 · NTSB Correspondence · Foreign, Brazil, Departamento de Aviacao Civil
We are aware that you asked Embraer to review the design and maintenance documentation for EMB-170/175/190/195/Lineage 1000 series airplanes and, following its review, Embraer improved its procedures for installing and maintaining the control column and associated electrical wiring on these airplanes. These improvements are detailed in SBs 170-27-0060, 190-27-0046, and 190LIN-27-0018; revised Fault Isolation Manual (FIM) Tasks 27-43-00-810-801-A and 27-43-00-810-802-A; and Aircraft Maintenance Manual (AMM) Tasks 27-31-01-820-801-A and 27 11-01-400-801-A.
Although the inspections outlined in the SBs developed by Embraer in response to Safety Recommendation A-20-1 have not been completed on all affected airplanes, we believe Embraer’s proactive actions, including reviewing the design and maintenance documentation for affected airplanes and revising its procedures to prevent wire chafing, are an acceptable alternate solution to Safety Recommendation A-20-3.
In addition, although you did not require operators of these airplanes to incorporate these changes, we believe regulators’ oversight of operators’ maintenance practices will ensure that operators have incorporated Embraer’s revised manual procedures and, therefore, represent an acceptable alternate solution to Safety Recommendation A-20-4. Accordingly, the Board has classified Safety Recommendations A-20-3 and -4 CLOSED-- ACCEPTABLE ALTERNATE ACTION.
May 13, 2024 · Recipient Response · Foreign, Brazil, Departamento de Aviacao Civil
-From Major General Marcelo Moreno, Chief of the Aeronautical Accident Investigation and Prevention Center: EMBRAER published modifications in maintenance procedures and design changes to be implemented by worldwide operators, and current field data did not suggest any need for more mandatory actions regarding modifications designed according to the recommendation A-20-3.
February 5, 2024 · NTSB Correspondence · Foreign, Brazil, Departamento de Aviacao Civil
We note that, so far, no damaged wiring has been discovered during the inspections that are being completed in response to Safety Recommendation A-20-2. We also note that you asked Embraer to review the design and maintenance documentation for EMB-170/175/190/195/Lineage 1000 series airplanes and, following its review, Embraer improved procedures for installing the control column and associated electrical wiring.