FAA legal interpretations are formal written opinions from the Federal Aviation Administration’s Office of the Chief Counsel that explain how a specific Federal Aviation Regulation should be read and applied. They are not regulations, and they never go through notice-and-comment rulemaking, but the FAA treats them as authoritative and can cite them when it moves to suspend or revoke a certificate. For pilots, mechanics, repair stations, and operators, that combination is what makes them worth understanding: an interpretation is the agency’s answer to what a rule actually requires, and in practice that answer is hard to argue with.
Who Issues Them and Why
Interpretations are issued by the Regulations Division (AGC-200) within the Office of the Chief Counsel. They exist because regulatory text runs into real-world situations the drafters didn’t spell out. A field office manager, a repair station, a pilot, or any member of the public can write in and ask what a rule means in a particular scenario, and the Chief Counsel’s office responds in writing.
The FAA’s own guidance page is explicit that guidance documents “lack the force and effect of law, unless expressly authorized by statute, regulation or incorporated into a contract.”1FAA. FAA Guidance Documents That disclaimer sits uneasily next to how interpretations are used. An interpretation can shift how a regulation is applied across the industry without any rulemaking, and once it is on the books the agency relies on it in enforcement.
Where They Sit in the Guidance Hierarchy
Legal interpretations are one layer in a stack of FAA material, and the differences among the layers matter.
- The Code of Federal Regulations (14 CFR) contains the binding rules themselves and carries the full force of law.2FAA. Code of Federal Regulations
- Advisory Circulars describe an “acceptable means, but not the only means” to comply with a regulation and are informational rather than binding.3FAA. FAA Order 1320.46D
- Orders, notices, handbooks, and manuals are largely internal guidance for FAA personnel, though publicly available.1FAA. FAA Guidance Documents
- Legal interpretations are the Chief Counsel’s official reading of what a regulation means. Not adopted through rulemaking, but treated by the FAA as authoritative for enforcement.
That last category is the one that punches above its formal weight. Because an interpretation can change the practical meaning of a regulation without any public comment period, it has been a recurring source of friction between the FAA and the aviation community.
How Much Weight They Carry in Enforcement
When the FAA proposes to suspend or revoke a certificate, the case is heard by the National Transportation Safety Board. The NTSB acts as an adjudicator, but its freedom to disagree with the FAA has been narrowed by statute and by the courts, and this is where legal interpretations translate into real consequences for certificate holders.
Under 49 U.S.C. § 44709(d)(3), the NTSB must defer to validly adopted FAA interpretations unless an interpretation is “arbitrary, capricious, or otherwise not according to law.”4FindLaw. Garvey v. NTSB The scope of that duty was set in Garvey v. National Transportation Safety Board, 190 F.3d 571 (D.C. Cir. 1999).5vLex. Garvey v. Nat’l Transp. Safety Bd. The NTSB had refused to defer to the FAA’s reading of 14 C.F.R. § 91.123, the rule on compliance with ATC instructions, and had substituted its own standard. The D.C. Circuit reversed, holding that the Board must defer to reasonable FAA interpretations of the agency’s own regulations even when those interpretations are advanced for the first time during litigation rather than through rulemaking. Where NTSB precedent conflicts with a reasonable FAA interpretation, the court said, the Board must “accommodate such policies by changing its jurisprudential course.”
The D.C. Circuit tightened the leash further in Pham v. National Transportation Safety Board (D.C. Cir. 2022). The NTSB had cut a certificate revocation down to a 180-day suspension after finding the airman had completed a return-to-duty process. The court held the Board exceeded its authority, ruling that “consistency with the FAA’s position is more important than consistency with the Board’s own [precedent]” and that the NTSB must defer to the FAA’s chosen sanction unless it is “unwarranted in law or is without justification in fact.”6FindLaw. Pham v. National Transportation Safety Board
The practical result is that if a Chief Counsel interpretation says a regulation means X, a certificate holder trying to argue Y in an enforcement hearing is fighting uphill from the start.
Interpretations Can Conflict, and They Can Be Reversed
An interpretation is not the last word forever. The Chief Counsel’s office handles requests one at a time, drafters change, and contradictory readings sometimes coexist on the books with no formal mechanism to reconcile them.
The clearest example involves Time Between Overhaul requirements for Special Light Sport Aircraft. In August 2013 the Willette interpretation stated that maintenance intervals in SLSA manuals are “not per se mandatory” and that providers could develop acceptable alternatives. In July 2015 the Keller interpretation stated the opposite: that an SLSA “would not be airworthy if operated beyond TBO.”7AOPA. Savvy Maintenance – Legal Interpretations A May 2016 request to resolve the conflict went nowhere; more than a year later, the requester was told the FAA’s Maintenance Division had declined to address the issue. Both interpretations remained on the books.
Industry pressure has, on occasion, forced the agency to withdraw an interpretation outright. In May 2010 the FAA read 14 CFR 121.377, the maintenance duty time rule, as requiring one day off in every seven and treating the regulation’s “equivalent” rest provision as an emergency-only option. After a formal complaint from the Aeronautical Repair Station Association, a Federal Register notice, and opposition from Airlines for America and the Transport Workers Union, the FAA withdrew the interpretation on December 26, 2012, acknowledging that “the requirement for equivalency lies in the amount of rest given, not in the way the schedule itself operates or is developed.”8Helicopter Maintenance Magazine. FAA Reverses Maintenance Duty Time Legal Interpretation
The most recent high-profile reversal involved supervision of uncertificated mechanics under 14 CFR § 43.3(d). On September 3, 2024, the Chief Counsel issued the Moss interpretation, concluding that “the phrase ‘in person’ explicitly requires physical presence” and requiring the certificated mechanic to be close enough to “notice mistakes and take over if necessary.” Critics read the language as barring remote video supervision entirely and effectively mandating side-by-side observation.9AOPA. Aircraft Maintenance: New FAA Interpretation Could Devastate GA A coalition of 16 organizations, including AOPA, EAA, GAMA, NBAA, and ARSA, sent a joint letter on October 10, 2024, arguing the interpretation “reversed years of well-established policy and contravened recognized legal precedent.”10ARSA. Supervision On October 15, 2024, the FAA stayed the Moss interpretation, saying it would remain suspended “until such time as the agency issues new or supplemental guidance.”11AIN Online. FAA Rescinds Burdensome Maintenance Interpretation As of late 2024, no replacement guidance had been finalized.12General Aviation News. FAA Stays Controversial Moss Interpretation After Industry Backlash
The lesson from all three episodes is the same. An interpretation is authoritative unless and until the agency changes its mind, and getting the agency to change its mind generally takes coordinated industry pressure.
Requesting an Interpretation Today
The bar for getting a new interpretation has gone up. Since October 2024, the Chief Counsel’s office only considers requests that present a “novel or legally significant issue,” as determined by the Chief Counsel.13FAA. Legal Interpretations and Chief Counsel’s Opinions Submitters are told whether the office accepts the request, but the FAA does not publish a timeline for how long the process takes. Routine questions that were once fair game are no longer likely to get a written answer.
Where to Find Existing Interpretations
Public interpretations and Chief Counsel’s opinions live in the FAA’s Dynamic Regulatory System at drs.faa.gov. The DRS aggregates more than 65 document types from 12 internal FAA repositories, holds over two million guidance documents in total, and is updated daily. You can filter by date, subject, or regulation part, and the system stores pending, current, and historical versions along with revision history.14FAA. Dynamic Regulatory System
Coverage runs from 1990 forward, and the FAA notes that not all interpretations from that period are available in the system.13FAA. Legal Interpretations and Chief Counsel’s Opinions For older material, or for interpretations that have not been digitized, contact the Office of the Chief Counsel directly.