FAA Aviation Safety Information Analysis and Sharing

Report Number A-21-042

General Information

Recommendation Number

A-21-042

Letter Date

2026 Mar 27

Subject

Assoc/ A-21-25 to -42; 04/22/2026: Exec Ltr review (AVS-1); 03/18/2026: Exec ltr review (AVP); 1/26/2026: Draft ltr recvd from AFX; Next PO Memo Due: 12/31/2026

NTSB Rec Status

OAA

Summary Document

Occurrence Text

Turbulence-related accidents are the most common type of accident involving air carriers operating under Title 14, Code of Federal Regulations Part 121. From 2009 through 2018, the National Transportation Safety Board (NTSB) found that turbulence-related accidents accounted for more than a third of all part 121 accidents; most of these accidents resulted in one or more serious injuries but no aircraft damage. The NTSB safety research report, Preventing Turbulence-Related Injuries in Air Carrier Operations Conducted Under Title 14 Code of Federal Regulations Part 121, examines the prevalence and risk factors of turbulence-related accidents in part 121 air carrier operations; assesses the effectiveness of policies, programs, technologies, and other applicable safety countermeasures; and makes recommendations for improving turbulence avoidance and injury mitigation.

Recommendation Text

A-21-42. Revise Advisory Circular 120-88A, “Preventing Injuries Caused by Turbulence,” to reflect current best practices and the findings of this research report, such as new turbulence forecasting and warning technologies; training methods; in-flight communications between pilots and flight attendants, procedures, and available information for predicting turbulence; and altitudes at which flight attendants should be secured in their seats.

Response Text

FAA LTR DTD: 11/19/2021 The FAA is reviewing part 121 requirements and associated guidance material that pertains to aircraft turbulence and injury prevention. Our review will determine if updates to part 121 and/or current guidance material are necessary to address turbulence-related injuries. I will keep the Board informed of the FAA’s progress on these recommendations and anticipate providing an update by December 31, 2022. NTSB LTR DTD: 5/04/2022 We note that you are reviewing Part 121 requirements and associated guidance that pertains to aircraft turbulence and injury prevention to determine if updates are needed. We believe your planned review is an appropriate first step to responding to these recommendations. Pending completion of that review and a plan for revising AC 120-88, Safety Recommendations A-21-38 and -42 are classified “Open—Acceptable Response.” FAA LTR DTD: 5/24/2023 The Federal Aviation Administration (FAA) continues to internally review 14 CFR Parts 91 and 121 requirements and associated guidance material pertaining to automatic dependent surveillance-broadcast and aircraft turbulence and injury prevention to determine the best action plan. Due to competing priorities and resources, we require additional time for discussions with various internal and external stakeholders to determine if updates to these requirements and/or current guidance material are necessary to address turbulence-related injuries. I will keep the Board informed of the FAA’s progress on Safety Recommendations A-21-26, -29, -38, and -42, and anticipate providing an update by April 30, 2024. NTSB LTR DTD: 1/03/2024 We note that your review of guidance that pertains to aircraft turbulence and injury prevention has been delayed. We are concerned that, in the two years since this recommendation was issued, you have not committed to revising Advisory Circular 120-88A. We encourage you to review our research report, which describes potential revisions—such as currently available technologies and best practices for avoiding turbulence encounters and turbulence-related injuries—that could be used by Part 121 air carriers to improve the safety of their flights. In the meantime, pending the recommended revisions to AC 120-88, Safety Recommendations A-21-38 and -42 are classified Open—Unacceptable Response. FAA LTR DTD: 1/08/2025 The FAA agrees with the Board and has initiated the revision process to update AC 120-88, Preventing Injuries Caused by Turbulence, to reflect current best practices. I believe the FAA has effectively addressed Safety Recommendation A-21-29 and plan no further action on this safety recommendation. I will keep the Board informed of the FAA’s progress on Safety Recommendations A-21-26, -38, and -42, and anticipate providing an update by December 1, 2025. NTSB LTR DTD: 03/27/2026 We are encouraged to learn that you have initiated the revision process to update AC 120-88 to reflect current best practices, as recommended. Pending our review of the revised guidance, the Board has classified Safety Recommendations A-21-38 and -42 Open—Acceptable Response.