Interpretation Response #25-0025
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name: West Virginia Flight Standards District Office (FSDO)
Individual Name: J. Brett Leslie
Location State: WV Country: US
View the Interpretation Document
Response text:
February 5, 2026
J. Brett Leslie, MBA
Aviation Safety Inspector – Ops., CRW-EA09
Flight Standards District Office (FSDO)
301 Eagle Mountain Rd. # 144
Charleston, WV 25311
Reference No. 25-0025
Dear Mr. Leslie:
This letter is in response to your March 5, 2025, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to special aircraft operations covered under § 175.9. You describe an operation in which a large saw, powered by gasoline, is attached to a rotorcraft (i.e., helicopter) and used to clear trees and vegetation to preserve rights of way for electrical transmission lines and railways.
We have paraphrased and answered your questions as follows:
Q1. Is the tree-trimming operation described above considered a "forest preservation and protection" activity for purposes of the exception from the HMR under § 175.9(b)(6)?
A1. Yes. It is the opinion of this Office that tree-trimming and vegetation clearing are activities covered under "forest preservation and protection" and applicable to this exception.
Q2. Are 14 CFR Part 133 rotorcraft operators eligible to use the exception for "forest preservation and protection" activities provided in § 175.9(b)(6) or would the operators be required to obtain a special permit to perform this clearing operation?
A2. Section 175.9(b) does not limit the special aircraft operations based on 14 CFR certification, such as 14 CFR Part 133. Therefore, Part 133 operators may qualify for the exceptions if they meet all appropriate HMR conditions and applicable Federal Aviation Administration (FAA) requirements. A special permit would be required if the operator is unable to meet the requirements specified in the HMR or applicable FAA requirements.
Q3. Must rotorcraft operators operating under the exception in § 175.9(b)(6) have a Letter of Authorization (LOA) A055 (Carriage of Hazardous Material)?
A3. Yes. A Part 133 rotorcraft operator who wishes to accept, handle, and transport hazardous materials must hold an LOA A055. To obtain an LOA A055, the operator must have a hazardous materials program, including hazardous materials training program and manual. See FAA Order 8900.1, Volume 3, Chapter 51, Section 7. For additional resources on rotorcraft operators transporting hazardous materials and the hazardous materials program requirements, see https://www.faa.gov/hazmat/air_carriers/operations/part_133.
Next, § 175.9(a) requires rotorcraft external load operations to be approved by the PHMSA Associate Administrator prior to the initiation of such operations and meet all provisions prescribed in 14 CFR Part 133—this requirement applies to all rotorcraft operations regardless of whether they take any of the special aircraft operation exceptions performed in accordance with § 175.9(b).
Furthermore, when operators, including Part 133 rotorcraft operators, meet certain special aircraft operational conditions outlined in § 175.9(b)—such as forest preservation and protection operations—they are eligible for exceptions from the HMR. In order for forest preservation and protection operations to be eligible for the § 175.9(b)(6) exception from the HMR, operators must meet all requirements outlined in § 175.9(b)(6)(i)-(v). This includes preparing and keeping current a manual containing operational guidelines and handling procedures, for the use and guidance of flight, maintenance, and ground personnel concerned in the dispensing or expending of hazardous materials. The manual must be approved by the FAA Principal Operations Inspector assigned to the operator. The hazardous materials manual used to obtain the LOA A055 may be used to meet this requirement.
Q4. Does the use of an exception for special aircraft operations, as provided in § 175.9(b)—i.e., forest preservation and protection operations—require the operator to have an FAA operating certificate approved under 14 CFR Part 133?
A4. The requirements of the FAA operating certificates approved under 14 CFR Part 133 are under the purview of the FAA. Questions regarding FAA regulations may be directed to FAA's Office of Hazardous Materials Safety at hazmatinfo@faa.gov.
Q5. Does § 175.9(b)(6) relieve the operator from the quantity limitations as indicated on the § 172.101 hazardous materials table (HMT) for the hazardous material that is intended to be dispensed or expended during the flight?
A5. Yes. Operations performed in accordance with § 175.9(b)(6) are excepted from the HMR, which includes the quantity limitations indicated in the HMT. However, note that the operations must still be conducted in accordance with the FAA-approved operator's manual.
I hope this information is helpful. Please contact us if we can be of further assistance.
Sincerely,
Dirk DerKinderen
Chief, Standards Development Branch
Standards and Rulemaking Division
§ 172.101, § 175.9, § 175.9(b), § 175.9(b)(6), § 175.9(b)(6)(i)-(v)