Safety Recommendation A-22-028

We continue to believe the actions required by Airworthiness Directive (AD) 2022-27-08, “Bell Textron Canada Limited,” are responsive to Safety Recommendation A-22-28; however, the compliance time specified in the AD did not ensure that operators complete those actions immediately, such as before the next flight, or within 5 hours time-in-service (TIS), which is the intent of this urgent recommendation. Consequently, Safety Recommendation A-22-28 is classified CLOSED-- UNACCEPTABLE ACTION.

-From Billy Nolen, Acting Administrator: As previously stated, the Bell 407 helicopter State of Design is Transport Canada Civil Aviation (TCCA). On December 6, 2022, the Federal Aviation Administration (FAA) and TCCA met to discuss the accident details and the Bell 407 certification standards. As a result of this meeting, TCCA issued Airworthiness Directive (AD) CF-2022-68, Fuselage Tailboom-Loss of Tailboom Attachment Hardware, on December 16, 2022, and effective on December 29, 2022. This AD is available at the following website:

https://wwwapps.tc.gc.ca/Saf-Sec-Sur/2/cawis-swimn/AD_dl.aspx?ad=CF-2022- 68&cn=CF&ft=pdf&l=E

Based on TCCA’s AD, the FAA issued AD 2022-27-08, Bell Textron Canada Limited Helicopters, on December 28, 2022 (87 FR 79794) and effective on January 12, 2023, incorporating TCAA’s AD by reference with few exceptions. Specifically, FAA AD 2022-27-08 requires aircraft owners and operators to complete an immediate visual inspection of the Bell 407 helicopter tail boom attachment fittings, conduct a one-time torque inspection of the tail boom attachment nuts, and then report the inspection findings to the FAA.

Currently, the FAA AD does not require repetitive inspections as recommended by Safety Recommendation A-22-29. We will continue to monitor this issue within the Bell 407 helicopter fleet to ensure the FAA’s safety risk mitigation efforts are maintained and satisfactory in addressing this safety recommendation.

I believe that the FAA has effectively addressed Safety Recommendation A-22-28 and consider our actions complete. I will keep the Board informed of the FAA’s actions on Safety Recommendation A-22-29 and anticipate providing an update by April 30, 2024.

We note that Airworthiness Directive (AD) 2022-27-08, “Bell Textron Canada Limited,” requires operators of Bell 407 helicopters to inspect the torque on the tail boom attachment hardware and visually inspect the tail boom attachment fittings, as specified in Transport Canada AD CF-2022-68. We also note that AD 2022-27-08 directs operators to complete these actions within 25 hours time-in-service (TIS) or 30 days, whichever occurs first, from January 12, 2023, which is the effective date of AD 2022-27-08. In addition, AD 2022-27-08 asks operators to report the findings of both inspections to the FAA within 10 days after completing these actions.

We believe the actions required by AD 2022-27-08 are responsive to Safety Recommendation A-22-28. However, the compliance time specified in AD 2022-27-08 does not ensure that those actions are completed immediately, such as before the next flight, or within 5 hours TIS, which is the intent of this urgent recommendation. We request that you send us the reported findings from the completed inspections as soon as possible. Pending our review of that information, Safety Recommendation A-22-28 is classified OPEN-- UNACCEPTABLE RESPONSE.

-From Billy Nolen, Administrator, FAA: In response to these urgent safety recommendations, the Federal Aviation Administration (FAA) met with Transport Canada Civil Aviation (TCCA), the State of Design for the Bell 407 Helicopter, on December 6, 2022. The TCCA indicated to the FAA that they are preparing to take action to address the issues identified in these recommendations. We intend to evaluate their action and, if appropriate, adopt their action for US operators.

Previously, the FAA contacted Bell 407 fleet associations, industry groups in the U.S., and others in the stakeholder community to highlight the separation of the tail boom from the helicopter in flight, beginning October 31, 2022. Additionally, on November 18, 2022, the FAA issued FAA Safety Team Notice NOTC2727: Bell 407 In-Flight Tail Boom Separation to raise awareness among owners and operators by highlighting key facts of the June accident and ongoing investigation, which was rebroadcasted on December 2, 2022, following the issuance of these safety recommendations. This notice is available at the following website: https://www.faasafety.gov/spans/noticeView.aspx?nid=12727

I will keep the Board informed of the FAA’s progress on Safety Recommendations A-22-28 and -29 and anticipate providing an update by December 31, 2023.

The attached letter from the NTSB Chair provides information about the December 1, 2022, report Require Immediate Inspection of Bell 407 Tail Boom Attachment Hardware and Fittings (NTSB/AIR-22-10). The details of this accident investigation and the resulting safety recommendations may be found in the attached report, which can also be accessed at http://www.ntsb.gov. The NTSB is vitally interested in these recommendations because they are designed to prevent accidents and save lives. We would appreciate a response within 90 days of the date of this letter, detailing the actions you have taken or intend to take to implement these recommendations.

When replying, please refer to the safety recommendations by number (for example, A-22-28 and -29). We encourage you to submit your response to ExecutiveSecretariat@ntsb.gov. If your reply exceeds 20 megabytes, including attachments, please e mail us at the same address for instructions on how to send larger documents. Please do not submit both an electronic copy and a hard copy of the same response. Justification for A-22-28 from the Aviation Investigation Report AIR-22-10 " Require Immediate Inspection of Bell 407 Tail Boom Attachment Hardware and Fittings," published December 1, 2022: Our investigation into this accident is ongoing.

However, given the findings thus far during the investigation, we are concerned that there may be additional Bell 407 helicopters with missing or fractured tail boom attachment hardware, and the potential for catastrophic failure warrants immediate and mandatory action. The NTSB concludes that any tail boom attachment hardware or fittings that is not installed properly or is fractured is a safety hazard because it can result in an inflight separation of the tail boom, which is catastrophic.

Therefore, the NTSB recommends that the FAA and Transport Canada require operators of Bell 407 helicopters to conduct an immediate torque check of the tail boom attachment hardware, as well as a visual inspection of the tail boom attachment fittings for evidence of cracks and fractures, and report findings to their respective regulatory authority. Our investigation has not yet determined why the upper-left tail boom attachment hardware separated on the accident helicopter.

Because the tail boom separated only 114.2 hours after its last torque check and visual inspection, the NTSB is also concerned that instances of improperly installed or fractured attachment hardware or fittings may not be detected within the existing 300-hour recurrent torque check and visual inspection interval and that an in-flight separation of the tail boom could occur on other Bell 407 helicopters. The separation of the upper-left attachment bolt may not result in an immediate separation of the tail boom but represents an impending catastrophic failure.