Safety Recommendation A-13-016

The National Transportation Safety Board (NTSB) has reviewed the Federal Aviation Administration’s (FAA) notice of proposed rulemaking (NPRM) titled “Requirements to File Notice for Meteorological Towers and Other Wind Energy Systems,” which was published at 89 Federal Register (FR) 90627 on November 18, 2024.

The NPRM proposes to amend requirements applicable to meteorological towers and permanent wind energy systems. Owners/sponsors of proposed, altered, or existing meteorological towers would be required to file notice with the FAA if the highest point of the structure is at least 50 ft above ground level (agl) up to and including 200 ft agl. The NPRM proposes marking requirements for meteorological towers constructed or altered after the effective date of a final rule if the highest point of the structure is at least 50 ft agl up to and including 200 ft agl.

Finally, the FAA would make available pertinent information about these same towers in the FAA’s official database, the Digital Obstacle File.

The NTSB has long been concerned about the hazards that meteorological towers pose to aviation operations conducted at low altitudes, such as agricultural operations, helicopter emergency medical services, law enforcement, animal damage control, fish and wildlife patrols, and aerial fire suppression. These structures can be erected quickly and, depending on their location, without notice to the local aviation community. In addition, they are often unmarked and unlighted because their height is typically just under the 200 ft agl threshold that currently requires FAA notification, including a marking and lighting plan.

We have issued a safety alert urging pilots to be vigilant for meteorological towers and two related safety recommendations to the FAA, A 13 16 and -17.

These safety recommendations asked the FAA to require that all meteorological towers be registered, marked, and lighted where feasible and to create and maintain a national public database for these structures. These recommendations resulted from the NTSB’s evaluation of three accidents that fatally injured four people in which airplanes operating at low altitude inadvertently collided with meteorological towers. Both recommendations are currently classified Open—Unacceptable Response (see the attached correspondence history of these recommendations for more information).

The NTSB supports the proposed rule changes requiring the filing of notice with the FAA. However, we are concerned that subsequent marking of meteorological towers if the highest point of the structure is at least 50 ft agl up to and including 200 ft agl would only apply to towers constructed or altered after the effective date of the NPRM. Decommissioned towers are not always removed and, therefore, may still pose a hazard.

The 2011 accident referenced in Safety Recommendation A-13-16 involved a tower for which the county permit had expired more than a year before the accident, but the meteorological evaluation tower had not been removed as stipulated by the permit’s conditions of approval. The intent of Safety Recommendation A-13-16 is to apply to all towers, including existing towers. Therefore, we encourage the FAA to address this concern in the final rule.

The NTSB also supports the requirement for every meteorological tower to be maintained in a national database. If this aspect of the NPRM were adopted as presented, it would likely satisfy the intent of Safety Recommendation A-13-17. We are concerned, however, that the proposed frequency at which you intend to update the database (every 56 days) is not sufficient to ensure that any meteorological towers that are erected between updates are referenced in the database.

The NTSB encourages the FAA to clearly communicate this timeline to database users in the event they are operating near a tower that has not yet been updated or added to the database, and to work to reduce the update timeline as technology allows.

We appreciate the opportunity to comment on this NPRM.

We note that your notice of proposed rulemaking (NPRM), “Requirements to File Notice of Construction of Meteorological Towers and Other Renewable Energy Projects,” has been delayed and is now expected to be published by the end of this year.

The FAA’s April 30, 2020, letter regarding this recommendation reported that the NPRM would be published by April 2021; however, it still has not been published. Although we continue to believe your plan to require MT registration, marking, and, when feasible, lighting, is responsive to this recommendation, we remain concerned about the continued delays associated with this rulemaking project. We encourage you to prioritize this rulemaking. In the meantime, pending our review of the published NPRM and final rule, Safety Recommendation A-13-16 remains classified OPEN-- UNACCEPTABLE RESPONSE.

LETTER FROM THE NATIONAL AGRICULTURAL AVIATION ASSOCIATION, NOT THE RECOMMENDATION RECIPIENT: -From Andrew D. Moore, National Agricultural Aviation Association (NAAA) Chief Executive Officer, NAAREF Executive Director:

NAAA/NAAREF Request for NTSB to Urge FAA to Address Tower Marking and Tower Safety Database Recommendations A-13-16—17

For nearly two decades NAAA has been advocating that national lawmakers and policymakers address the safety hazards posed by unmarked towers below 200 feet, so when the NTSB included safety recommendation A-13-17 and -17 for the FAA to require marking and a database for towers posing safety risks to low-altitude, manned aviation it was embraced by NAAA. NAAA used the NTSB’s recommendation to advocate to Congress to include Section 2110 within the FAA Extension, Safety and Security Act of 2016 - §2110 that directed the FAA to issue regulations to require marking (consistent with AC 70/7460-1) for all towers 10 feet or less in diameter and 50-200 feet AGL located in rural/agricultural areas.

In addition, the FAA was directed to develop a database to log the location and height for each tower to be used for aviation safety purposes. Unfortunately, two years later, to appease the telecommunications industry, Section 576 of the FAA Reauthorization Act of 2018 amended the 2016 act to allow applicable towers to be either marked or logged, however meteorological evaluation towers (METs) were still required to be marked and logged. In that same year NAAA appreciated the NTSB updating its Safety Alert (SA-016) to include language stating aviation safety concerns about “other kinds of towers less than 200 feet tall...”

The enacted legislation required FAA to address this safety concern by issuing a Notice of Proposed Rulemaking (NPRM) in 2020. However, several years later, no action has been taken and the issue remains unresolved. In the recently enacted FAA Reauthorization Act of 2024 Congress included Section 355 requiring the FAA, within a year, to issue a notice of proposed rulemaking to implement section 2110 of the FAA Extension, Safety, and Security Act of 2016 or explain to Congress the reasons for failing to do so and to provide a list of fatal aircraft accidents associated with unmarked towers in the past five years.

For Part 137

-From Michael G. Whitaker, Administrator: The Requirements to File Notice of Construction of Meteorological Towers and Other Renewable Energy Projects Notice of Proposed Rulemaking (MT NPRM) continues to be delayed due to resource limitations resulting from other FAA rulemaking priorities. However, the FAA published a policy statement in the Federal Register (87 FR 78849) regarding airborne wind energy systems (AWES), removing an NPRM publication prerequisite, and approved a revised schedule to track NPRM progress. The FAA now anticipates publication of the MT NPRM to occur by December 31, 2024.

We note that your notice of propose+-d rulemaking (NPRM), “Requirements to File Notice of Construction of Meteorological Evaluation Towers and Other Renewable Energy Projects,” is now expected in December of this year. We continue to believe your plan to require MET registration, marking, and, when feasible, lighting, is responsive to this recommendation; however, we remain concerned about the continued delays associated with this rulemaking project. Pending our review of the published NPRM and final rule, Safety Recommendation A-13-16 remains classified OPEN-- UNACCEPTABLE RESPONSE.

-From Billy Nolen, Acting Administrator: The Requirements to File Notice of Construction of Meteorological Evaluation Towers and Other Renewable Energy Projects Notice of Proposed Rulemaking (METs NPRM) continues to be delayed due to resource limitations resulting from other FAA rulemaking priorities. The anticipated publication date of the METs NPRM is now December 31, 2023.

We are disappointed that your Notice of Proposed Rulemaking, “Requirements to File Notice of Construction of Meteorological Evaluation Towers and Other Renewable Energy Projects,” has been delayed until April 30, 2022. We understand that the final rule will require MET registration, marking, and, when feasible, lighting, and that you intend to create a national MET database after the final rule is enacted. The FAA Reauthorization Act of 2018, which was enacted on October 5, 2018, requires that you make the MET database available by October 5, 2019. The legislation also requires that METs be marked and included in the database 18 months after the database is published.

We are disappointed that you missed these statutory deadlines. Pending publication of the final rule, Safety Recommendations A 13-16 and -17 are classified OPEN-- UNACCEPTABLE RESPONSE.

-From Steve Dickson, Administrator: As stated in our April 30, 2020, letter to the Board, the Requirements to File Notice of Construction of Meteorological Evaluation Towers and Other Renewable Energy Projects Notice of Proposed Rulemaking (NPRM) (2120-AK77) was delayed. Due to continued delays resulting from various rulemaking priorities, the anticipated publication date of the NPRM is now April 30, 2022.

We note that rulemaking activity to address Safety Recommendation A-13-16 has been delayed due to the government shutdown and because of 2018 legislation that added additional requirements to be addressed in the rulemaking. It is our understanding that, in addition to requiring MET sponsors and owners to file a notice of proposed construction or alteration with the FAA, the rulemaking will also require METs to be registered, marked, and, where feasible, lighted. We also note that you have identified a publicly accessible national database for all METs, but that you do not intend to implement the database until the requirements described above become effective.

Although we normally expect our recommendations to be implemented within 5 years, we realize the new legislation, government shutdown, and challenges in identifying an appropriate database for storing METs data have delayed your efforts. Pending the timely issuance of a notice of proposed rulemaking and final rule, Safety Recommendation A-13-16 remains classified OPEN--ACCEPTABLE RESPONSE. Pending the implementation of a publicly accessible national database for all METs, Safety Recommendation A-13-17 remains classified “Open—Acceptable Response.”

Please update us at ExecutiveSecretariat@ntsb.gov on your progress toward implementing these recommendations, and do not submit both an electronic and a hard copy of the same response.

-From Steve Dickson, Administrator: The Federal Aviation Administration (FAA) Rulemaking Management Council approved a re-baseline schedule for this rulemaking activity due to the government shutdown, and the 2018 legislation that added additional requirements to be addressed in the rulemaking.

Based on current rulemaking priorities, the anticipated date of publication for the Requirements to File Notice of Construction of Meteorological Evaluation Towers and Other Renewable Energy Projects Notice of Proposed Rulemaking (2120-AK77) is April 2021.

We note that you intend to propose a change to Part 77 that would require MET sponsors and owners to file a notice of proposed construction or alteration with the FAA. Although this is a first step to ensuring that all METs are registered, we would like to know how you intend to ensure that these structures are also marked and lighted. Pending our review of this information and your proposed revisions to Part 77, Safety Recommendation A-13-016 remains classified OPEN—ACCEPTABLE RESPONSE.

-From Michael P. Huerta, Administrator: The Federal Aviation Administration (FAA) is considering a change to Title 14. Code of Federal Regulations Part 77 that will expand notice criteria to include METs and require sponsors and owners of these structures to file a Notice of Proposed Construction or Alteration with the FAA. Currently, the proposed amendment is scheduled to be published in a notice of proposed rulemaking (NPRM) in April 20 17. After the NPRM's 90-day comment period, we will review and reconcile all comments before issuing a final determination.

I will keep the Board informed of the FAA's progress on this safety recommendation and provide an update by June 20 I 7.

We note that you completed an MET study, that the associated report is currently under executive review, and that you plan to give us a copy of the report once the review is finished. We also note that you completed a draft of Advisory Circular (AC) 70-7460-1, “Obstruction Marking and Lighting,” which you expect to publish shortly. Although both of these actions are positive steps, we point out that neither the release of the report nor the publication of the AC will satisfy these recommendations. After completing these actions, you will still need to revise 14 CFR Part 77, collect the information produced into a database, and make the database available to the public.

Pending completion of the recommended actions, Safety Recommendations A-13-16 and-17 remain classified OPEN—ACCEPTABLE RESPONSE.

-From Michael P. Huerta, Administrator: The Federal Aviation Administration (FAA) completed a MET study and an associated report. The study and report are under executive review within the U.S. Department of Transportation. We expect to complete the review within 6 months. At that time, the study and report will be provided to the Board.

Additionally, the FAA completed the final draft of Advisory Circular (AC) 70-7460-1, Obstruction Marking and Lighting. The anticipated publication date was changed to April 2015 due to the need for additional research and development of the AC. After final AC edits are completed, it will be coordinated with all of the FAA's lines of business for review and concurrence.

I will update the Board on the progress of these recommendations and provide a response by November 30, 2015.

We note that, although you had originally anticipated completing your analysis by the end of FY 2013, because of limited resources and competing priorities, you are still analyzing the impact of METs on aircraft operations and will update us on your progress by November 2014.

We understand that the many congressionally mandated rulemaking projects have strained FAA rulemaking resources, but we are concerned that, in the absence of a federal requirement concerning METs, we will continue to see similar accidents. Therefore, we urge you to complete your analysis and develop a plan for addressing the safety issues identified in these recommendations without further delay. Pending our receipt and review of this information, Safety Recommendations A-13-16 and -17 remain classified OPEN—ACCEPTABLE RESPONSE.

-From Michael P. Huerta, Administrator: The Federal Aviation Administration’s Air Traffic Organization is currently analyzing the impact of METs on aircraft operations. Due to limited resources and competing priorities, we anticipate completing our analysis by September 2014.

I will keep the Board informed of the FAA's progress on these safety recommendations and provide an update by November 2014.

We look forward to reviewing the findings of the FAA’s Air Traffic Organization’s analysis of METs and a plan for addressing the safety issues identified in these recommendations. Pending our receipt and review of this information, Safety Recommendations A-13-16 and -17 are classified OPEN—ACCEPTABLE RESPONSE.

-From Michael P. Huerta, Administrator: The Federal Aviation Administration's Air Traffic Organization is currently analyzing METs. We anticipate completing our analysis by September 2013.

I will keep the Board informed of the FAA's progress on these safety recommendations and provide an update by January 31, 2014.