After Two Decades of NAAA Advocacy, FAA Proposes Requirements for Marking and Logging Locations of Meteorological Towers 

Following nearly two decades of lobbying by NAAA, the FAA has issued a Notice of Proposed Rulemaking (NPRM) to codify requirements for owners (termed “sponsors” by FAA) of meteorological towers (METs) to identify them in the interest of low-altitude aviation safety. Specifically, this NPRM applies to all existing METs, as well as proposals to construct or alter a MET, with the highest point of the structure at least 50 feet AGL up to and including 200 feet AGL, hereafter referred to as an “applicable MET.” 

Sponsors of proposed applicable METs will now be required to file a Notice of Proposed Construction or Alteration (notice) with FAA, who will conduct an aeronautical study and issue a determination stating whether the proposed construction or alteration would be a hazard to air navigation. If a Determination of No Hazard to Air Navigation is issued, it will include marking and lighting requirements determined using Advisory Circular 70/7460-1. This NPRM explicitly codifies the requirement to mark newly constructed or altered applicable METs. 

Sponsors of existing applicable METs, whether active or inactive, will be required to file notice within 90 days of the Final Rule. Structures which have already received a Determination of No Hazard to Air Navigation and applicable METs for which construction is completed prior to the Final Rule will not be subject to marking requirements. 

The FAA plans to update the existing Obstruction Evaluation/Airport Airspace Analysis (OE/AAA) online airspace obstruction mapping tool to include filters for METs. With the NPRM’s proposed requirement of all existing and proposed MET Sponsors to file notice, this database will become a comprehensive source for MET information including structure type, location, height, elevation and marking. In addition, OE/AAA includes functionality to subscribe via email for updates on new obstructions in a pre-defined geographical area. 

While NAAA is still processing this NPRM, there is no question that this is excellent news for the safety of aerial applicators and a victory for the association. A national database of METs will serve as a preflight planning tool and the requirement for sponsors to file notice will ensure applicators aren’t caught off guard by a tower erected overnight when the sponsor properly follows these proposed regulations. Further, the proper marking of all future METs and associated guy wires will aid in maintaining situational awareness in the field. 

Comments on this NPRM are due January 17, 2025. NAAA will be submitting comments in support of it and will be organizing a grassroots campaign encouraging aerial applicators across the country to also submit supportive comments.