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  3. NTSB A-15-032
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NTSB · Safety Recommendation

Safety Recommendation A-15-032

Recommendation

TO THE FEDERAL AVIATION ADMINISTRATION: Develop and issue guidance on the appropriate use and limitations of the review of engineering drawings in a design review performed as a means of showing compliance with certification regulations.

Safety Issue and Context

On May 31, 2014, about 2140 eastern daylight time, a Gulfstream Aerospace Corporation G-IV, N121JM, registered to SK Travel, LLC, and operated by Arizin Ventures, LLC, crashed after it overran the end of runway 11 during a rejected takeoff at Laurence G. Hanscom Field (BED), Bedford, Massachusetts. The airplane rolled through the paved overrun area and across a grassy area, collided with approach lights and a localizer antenna, passed through the airport’s perimeter fence, and came to a stop in a ravine. The two pilots, a flight attendant, and four passengers died. The airplane was destroyed by impact forces and a postcrash fire.

The corporate flight, which was destined for Atlantic City International Airport, Atlantic City, New Jersey, was conducted under the provisions of 14 Code of Federal Regulations (CFR) Part 91. An instrument flight rules flight plan was filed. Night visual meteorological conditions prevailed at the time of the accident. The NTSB determines that the probable cause of this accident was the flight crewmembers’ failure to perform the flight control check before takeoff, their attempt to take off with the gust lock system engaged, and their delayed execution of a rejected takeoff after they became aware that the controls were locked.

Contributing to the accident were the flight crew’s habitual noncompliance with checklists, Gulfstream Aerospace Corporation’s failure to ensure that the G-IV gust lock/throttle lever interlock system would prevent an attempted takeoff with the gust lock engaged, and the Federal Aviation Administration’s failure to detect this inadequacy during the G-IV’s certification.

Response History

February 9, 2026 · Recipient Response · FAA

The planned FAA activities for this SR continue with the final action item to close it out anticipated to be completed within a month or so. A final letter will be forthcoming once the advisory circular is published. AIR Input (in part) –

“…publish a new Advisory Circular (AC) 21-60, Means of Compliance. We had anticipated publication of the final AC in March 2025; however, during a final internal review we uncovered an issue requiring further clarification and re-evaluation by legal counsel. We completed revisions in September 2025, and have been working to complete final internal coordination, with intent to now publish the AC in the first quarter of calendar year 2026.”

Please accept this message as our email status update at this time.

February 9, 2026 · NTSB Correspondence · FAA

On February 9, 2026, FAA staff informed us that they are continuing work on Safety Recommendation A-15-32. We look forward to your next update when the proposed Advisory Circular (AC) is published.

March 19, 2025 · NTSB Correspondence · FAA

On March 12, 2025, FAA Acting Administrator Christopher J. Rocheleau informed us that the agency is continuing the work described in its previous letter regarding Safety Recommendation A-15-32. We look forward to receiving your next update.

March 12, 2025 · Recipient Response · FAA

-From Christopher J. Rocheleau, Acting Administrator: The Federal Aviation Administration (FAA) has concluded its review and disposition of the public comment submissions involving the new Advisory Circular (AC) 21-60, Means of Compliance. The AC is currently undergoing one last internal FAA review before its publication. We anticipate publishing the final AC by March 31, 2025.

Read Recommendation

Recommendation Facts

Status
Open - Acceptable Response
Issued
September 24, 2015
Priority
CLASS II
Recipient
FAA
Adopted
September 22, 2015
Related Investigation
ERA14MA271
Related Report
AAR-15-03

I will keep the Board informed of the FAA’s progress on Safety Recommendation A-15-32 and anticipate providing an update by February 28, 2026.

November 26, 2024 · NTSB Correspondence · FAA

We are encouraged to learn that, on October 26, 2023, you published a draft means of compliance advisory circular (AC) for public comment. Pending our review of the published final AC, Safety Recommendation A-15-32 remains classified OPEN-- ACCEPTABLE RESPONSE.

April 24, 2024 · Recipient Response · FAA

-From Michael G. Whitaker, Administrator: Upon completing all additional modifications, the Federal Aviation Administration (FAA) released the new draft means of compliance advisory circular for public comment on October 26, 2023, in response to the Aircraft Certification, Safety, and Accountability Act of 2020. The comment period closed on November 26, 2023, and we are currently reviewing comments.

I will keep the Board informed of the FAA’s progress on Safety Recommendation A-15-32 and anticipate providing an update by March 31, 2025.

October 24, 2023 · NTSB Correspondence · FAA

We note that you continue to develop the separate means of compliance advisory circular (AC), which has been delayed due to additional modifications that were needed in response to the Aircraft Certification, Safety, and Accountability Act of 2020. We look forward to reviewing the draft AC once it is available for public comment later this year. Pending the published guidance, Safety Recommendation A-15-32 remains classified OPEN-- ACCEPTABLE RESPONSE.

May 24, 2023 · Recipient Response · FAA

-From Billy Nolen, Acting Administrator: The Federal Aviation Administration (FAA) continues to work towards issuing a new advisory circular (AC) to provide guidance to applicants when proposing means of compliance within certification plans (e.g., design review, analysis, and testing), which will address the intent of this safety recommendation.

This AC has been delayed in its development phase due to further review and modifications in order to be responsive to the Aircraft Certification, Safety, and Accountability Act of 2020. We anticipate releasing the proposed AC for public comment prior to publication of the final AC. We anticipate publication of the final AC by December 31, 2023.

I will keep the Board informed of the FAA’s progress on Safety Recommendation A-15-32 and anticipate providing an update by April 30, 2024.

September 28, 2022 · NTSB Correspondence · FAA

We note that you still plan to develop a separate means of compliance (MOC) advisory circular (AC) with guidance that will discourage applicants from relying solely on engineering drawings as a MOC, recommend additional functional testing and analysis to increase overall safety and compliance, and further clarify the MOC process and proper use of engineering drawings as a needed step in identifying other areas for functional testing and analysis.

We note, however, that the MOC AC will no longer include a means for verifying (by the applicant or the FAA) the MOC used for the certification project or a method to generate a statement of compliance in accordance with section 21.20 (a) and (b), as this is already addressed in AC 21-51. We also note that you no longer intend to revise AC 21-51 because the guidance is still valid.

We believe your updated plan is responsive to this safety recommendation and we look forward to reviewing the published MOC AC later this year. In the meantime, pending our review of the published guidance, Safety Recommendation A-15-32 remains classified OPEN--ACCEPTABLE RESPONSE.

January 26, 2022 · Recipient Response · FAA

-From Steve Dickson, Administrator: The Federal Aviation Administration (FAA) agrees with this recommendation and the need for additional guidance for showing compliance with airworthiness standards.

In our October 23, 2019, letter to the Board, the FAA stated:

The best approach to successfully address this recommendation is to separate means of compliance (MOC) from this Advisory Circular (AC) [21-51, Applicant’s Showing of Compliance and Certifying Statement of Compliance]. In developing and issuing this new AC, the FAA is no longer revising AC 21-51 to provide better guidance on language used in Title 14, Code of Federal Regulations Part 21.20, Compliance with Applicable Requirements.

We want to correct a statement in our October 23, 2019 letter that says, “the best approach to address this recommendation successfully is to separate MOC from this AC.” We will not remove the MOC discussion from AC 21-51. AC 21-51, as currently written, remains valid, and we have no plans to update this AC at this time.

The FAA continues to believe that the best approach to address this safety recommendation successfully is to prepare the separate MOC AC, which provides information to guide an applicant’s proposed means of compliance within the certification plan (e.g., design review, analysis, and testing). The FAA previously stated that the MOC AC would also provide means for verification (by the applicant or the FAA) of the MOC used for the certification project and a method to generate a statement of compliance in accordance with § 21.20 (a) and (b).

Section 21.20 (b) requires applicants to provide a statement certifying that the applicant has complied with the applicable requirements; because this is already addressed in AC 21-51, we will not be adding this verbiage to the MOC AC. In issuing § 21.20, the FAA is enforcing the applicant’s responsibility of compliance by requiring the applicant to provide the MOC and statement of compliance to the FAA with subsequent FAA verification. The Gulfstream Model G-IV aircraft was type certificated before that promulgated requirement.

The Bedford accident findings stated that the FAA had “missed opportunities to detect” insufficiencies in the gust-lock system because it relied solely on engineering drawings and not field-testing. The MOC AC will include information that discusses the problems with relying solely on engineering drawings as a means of compliance and that additional functional testing and analysis are necessary for increasing overall safety and compliance. The MOC AC will further clarify the MOC process and proper use of engineering drawings as a needed step in identifying other areas for functional testing and analysis, helping to prevent future accidents like Bedford.

We previously informed the Board that the MOC AC would be published by December 31, 2020. In light of the Aircraft Certification, Safety, and Accountability Act of 2020 and the agency’s work to implement its requirements, the FAA is reviewing the draft MOC AC and other draft policy and guidance to ensure that it is responsive to the legislation. We now anticipate publication to occur by December 31, 2022. I will keep the Board informed of our progress with Safety Recommendation A-15-32 and anticipate providing an update by March 31, 2023.

January 21, 2020 · NTSB Correspondence · FAA

We note that you intend to remove means of compliance from Advisory Circular (AC) 21 51, “Applicant’s Showing of Compliance and Certifying Statement of Compliance,” and develop a new AC that includes guidance on the appropriate use and limitations of the review of engineering drawings during a design review. We also note that the new AC will provide means for the applicant or the FAA to verify the method of compliance used in the certification program, as well as a method to generate a statement of compliance in accordance with sections 21.20(a) and 21.20(b).

Pending issuance of a new AC that addresses the issue in Safety Recommendation A 15-32, it remains classified OPEN--ACCEPTABLE RESPONSE.

October 23, 2019 · Recipient Response · FAA

-From Steve Dickson, Administrator: As noted in our previous letters, the Federal Aviation Administration (FAA) agrees that more specific guidance about the appropriate use and limitations of showing compliance to airworthiness standards may add safety value to the certification process. In our letter dated July 10, 2017, the FAA determined that a revision to Advisory Circular (AC) 21-51 , Applicant's Showing of Compliance and Certifying Statement of Compliance, was the most appropriate course of action to address this safety recommendation.

The best approach to successfully address this recommendation is to separate means of compliance from this AC. In developing and issuing this new AC, the FAA is no longer revising AC 21-51 to provide better guidance on language used in Title 14, Code of Federal Regulations Part 2 1.20, Compliance with Applicable Requirements. The new stand-alone AC will not only address the use of drawings, but will also provide other means to guide applicant's certification plan in regards to a Method of Compliance (MOC), such as; similarity by comparison, ground, flight test, compliance inspection, etc.

The new stand-alone AC will also provide means for verification (by the applicant or the FAA) of the MOC used in the certification program and a method to generate a statement of compliance in accordance with §21.20(a) and §21.20(b). The December 2020 date takes into consideration the technical aspects associated with creating a stand-alone AC, and the additional layers of review required by the Office of the Chief Counsel. We anticipate this new AC being published by December 2020.

I will keep the Board informed of the FAA's progress on this recommendation and anticipate providing an update by March 2021.

August 23, 2017 · NTSB Correspondence · FAA

We agree with your determination that a revision to Advisory Circular (AC) 21-51, “Applicant’s Showing of Compliance and Certifying Statement of Compliance,” will satisfy this recommendation, and we note that you are currently revising that AC. Pending issuance of a revised AC that addresses the issue in Safety Recommendation A-15-32, it remains classified OPEN--ACCEPTABLE RESPONSE.

July 10, 2017 · Recipient Response · FAA

-From Michael P. Huerta, Administrator: As stated in our letter dated December 9, 2015, the Federal Aviation Administration (FAA) provides generic guidance materials concerning various means of showing compliance in FAA Order 8110.4C, Type Certification, Advisory Circular (AC) 21 -40A, Guide for Obtaining a Supplemental Type Certificate, and AC 21-51 , Applicant' s Showing of Compliance and Certifying Statement of Compliance. The FAA agrees that more specific guidance about the appropriate use and limitations of showing compliance to airworthiness standards may add safety value to the certification process.

After a thorough review of all published guidance materials related to the certification process, it was determined that a revision to AC 21 -51 is the most appropriate course of action to address this safety recommendation.

As a result, the FAA is revising AC 21-51 to provide better guidance on the intended meaning of language used in 14 CFR 21.20. The FAA Office of the Chief Counsel has directed issuance of a technical amendment to§ 21.20 to permit different treatment of domestic and foreign applicants that is consistent with FAA 's strategic Global Leadership Initiative. The AC is expected to enter internal coordination and review by September 20 17. The targeted publication date is September 2018.

I will keep the Board informed of the FAA's progress on these recommendations and provide an update by October 31, 2018.

March 15, 2016 · NTSB Correspondence · FAA

We note that, after you have completed your review of existing guidance, you intend to develop specific guidance about appropriate use and limitations of different means of showing compliance to airworthiness standards. Pending the development and issuance of the recommended guidance, Safety Recommendation A-15-32 is classified OPEN—ACCEPTABLE RESPONSE.

December 9, 2015 · Recipient Response · FAA

-From Michael P. Huerta, Administrator: The FAA currently provides generic guidance materials concerning various means of showing compliance in publications, such as FAA Order 811 0.4C, Type Certification, Advisory Circular (AC) 21 -40A, Guide for Obtaining a Supplemental Type Certificate, and AC 21-51, Applicants Showing Compliance and Certifying Statement of Compliance. We agree that more specific guidance about appropriate use and limitations of different means of showing compliance to airworthiness standards may add safety value to the certification process.

We will perform a thorough review of all published guidance materials and determine areas where more specific guidance would be most appropriate by the end of the September 2016.

I will keep the Board informed of the FAA's progress on these recommendations and provide an update by December 2016.