Direct Answer
Under 14 CFR §135.21, every Part 135 certificate holder except a true single-pilot operator must prepare and keep current a manual of its procedures and policies acceptable to the FAA. The industry calls it the General Operations Manual (GOM).
The required contents are specified in 14 CFR §135.23 — nineteen lettered categories from management personnel and weight-and-balance procedures to hazardous-materials handling and a copy of (or extract from) the operations specifications. When the operator maintains its own aircraft, 14 CFR §135.427 adds the maintenance organization and the §135.425 maintenance programs — the part the industry calls the General Maintenance Manual (GMM).
The manual must be kept at the principal base of operations (§135.21(b)), furnished to flight crew and the Administrator and made available to ground and maintenance staff (§135.21(d)), kept current and free of conflict with the operations specifications (§135.21(a), (c)), and be clearly displayed and retrievable in English (§135.21(g)). Most findings are not about what the manual says — they are about whether the current revision was actually distributed, acknowledged, and aligned to the operator's authorizations.
One Manual, Two Trade Names
The terms "General Operations Manual" and "General Maintenance Manual" do not appear in the regulation. The CFR simply refers to "a manual" in §135.21 and specifies its contents in §135.23. The operational content of that manual is what the industry calls the GOM. Where the operator performs its own maintenance under a continuous airworthiness program or an approved aircraft inspection program, §135.427 requires additional maintenance content — and that content is what the industry calls the GMM (or Maintenance Operations Manual). They are commonly bound as two physical volumes so that operations and maintenance personnel each carry the part relevant to their assigned duties, but the FAA treats both as the operator's manual.
The single-pilot exception in §135.21(a) is narrow and literal: it applies to a certificate holder who uses only one pilot in its operations. The moment a second pilot flies under the certificate, the manual requirement attaches. The Administrator may also authorize a deviation under §135.21(a) for a limited-size operation if all or part of the manual is not necessary for the guidance of flight, ground, or maintenance personnel — but that is a discretionary authorization granted by the FAA, not a self-executing exemption.
Critically, §135.21(c) prohibits the manual from being contrary to any applicable Federal or foreign regulation, the operator's operating certificate, or its operations specifications. This is the requirement that links manual currency to your operations specifications: when the FAA amends your operations specifications, adds an aircraft, or grants a new authorization, the manual must be revised so it does not contradict the new authority. For how those authorizations are tracked alongside the manual, see our guide on operational control in Part 135 and the full Part 135 records set.
The manual is the framework — its failures cascade
Because §135.23 requires the manual to contain the procedures for nearly every operation the certificate authorizes — flight locating, mechanical-irregularity reporting, refueling, passenger briefing, emergency assignments — a deficiency in the manual frequently surfaces first as a downstream finding in one of those areas. The root cause, though, is upstream: a manual that was not current, not distributed, or not consistent with the operations specifications.
For the wider obligations that surround the manual, see the Part 135 on-demand charter compliance overview and the full FAA aviation compliance hub.
What §135.23 Requires the GOM to Contain
14 CFR §135.23 is a closed list of nineteen lettered categories. Not every category applies to every operator — flight locating, en route qualification, and destination-airport analysis are conditioned on the type of operation — but each that does apply must be addressed in the manual. The table below maps each lettered paragraph to what it requires.
Management personnel and operational control authority
The name of each person authorized to act for the certificate holder in a management position required under §119.69(a) — Director of Operations, Chief Pilot, and Director of Maintenance — with the areas of responsibility assigned to them, and the names of persons authorized to exercise operational control under §135.77.
Weight and balance
Procedures for ensuring that the aircraft is loaded and operated within its weight-and-balance limitations, and for multiengine aircraft, that §135.185 is met.
Operations specifications
A copy of the operations specifications, or appropriate extracted information, including the area of operations authorized, the category and class of aircraft, crew complement, and the type of operation involved.
Accident notification
Procedures for complying with the accident notification requirements.
Airworthiness and return to service
Procedures ensuring the pilot in command knows that the required airworthiness inspections have been made and the aircraft has been approved for return to service in compliance with applicable maintenance requirements.
Mechanical irregularity reporting
Procedures for reporting and recording mechanical irregularities that come to the attention of the pilot in command before, during, and after completion of a flight.
Prior defect correction
Procedures for the pilot in command to use in determining that mechanical irregularities or defects reported for previous flights were corrected, or that correction was deferred.
Maintenance away from base
Procedures for the pilot in command to obtain maintenance, preventive maintenance, and servicing of the aircraft at a place where prior arrangements have not been made, and procedures for recording it.
Inoperative equipment
Procedures under §135.179 for the release for, or continuation of, flight if any item of equipment required for a particular type of operation becomes inoperative or unserviceable en route.
Refueling and fire safety
Procedures for refueling aircraft, eliminating fuel contamination, protecting from fire (including electrostatic protection), and supervising and protecting passengers during refueling.
Passenger briefing
Procedures to be followed by the pilot in command for the briefing of passengers under §135.117.
Flight locating
Procedures for ensuring compliance with the flight locating requirements, where they apply to the operation.
Emergency procedures
Emergency procedures, including the assignment of crewmember functions and duties in emergency situations and the procedures for the evacuation of persons in an emergency.
En route pilot qualification
Procedures for ensuring compliance with the en route pilot qualification requirements, where they apply.
Approved aircraft inspection program
The approved aircraft inspection program, where applicable.
Hazardous materials
Procedures and information to assist personnel in recognizing, handling, and being responsible for the acceptance, rejection, handling, storage incidental to transportation, packaging aboard the aircraft, and loading of hazardous materials, where it is applicable.
Evacuation assistance
Procedures for the evacuation of persons who may need the assistance of another person to move expeditiously to an exit, if those persons are carried.
Destination-airport analysis
If required by §135.385, an approved destination-airport analysis establishing runway-safety margins, with criteria for evaluating the operator's ability to land at the destination.
Other procedures
Other procedures and policy instructions regarding the certificate holder's operations that are issued by the certificate holder or the Administrator.
The §135.23(c) operations-specifications extract is the most fragile section
Section 135.23(c) lets you include either the full operations specifications or "appropriate extracted information." An extract is easier to read but harder to keep current — every operations-specifications amendment must be reflected, or the manual quietly drifts out of compliance with §135.21(c). Operators who extract the operations specifications into the GOM should treat every operations-specifications amendment as an automatic manual-revision trigger.
Several §135.23 categories tie directly to records you must independently keep. For the documentary side of those obligations, see:
Part 135 pilot records · training program recordkeeping · required management personnel · MEL / CDL records · weight-and-balance records
The General Maintenance Manual: §135.427 and §135.425
If your certificate holder maintains its own aircraft — rather than contracting all maintenance to a Part 145 repair station — then §135.427 requires specific maintenance content in the manual. This is the portion the industry calls the General Maintenance Manual. The underlying maintenance and inspection programs are established by §135.425, and §135.427 is what requires those programs to be written into the manual.
§135.427(a) — Organization and contracted persons
14 CFR §135.427(a) / §135.423What it requires
The manual must contain the chart or description of the certificate holder's organization required by §135.423, and a list of the persons with whom the operator has arranged for the performance of any required inspections, other maintenance, preventive maintenance, or alterations, together with a general description of that work. This is how the FAA sees, on paper, who is responsible for maintenance and which outside vendors touch the aircraft.
How FileFlo tracks it
FileFlo classifies the organization chart, the contracted-maintenance vendor list, and each vendor's scope description as document categories tied to the maintenance manual revision, with expiration tracking on any vendor agreement.
§135.427(b) — The §135.425 maintenance programs
14 CFR §135.427(b) / §135.425What it requires
The manual must set out the programs required by §135.425 that personnel must follow in performing maintenance, preventive maintenance, and alterations. These include the method of performing routine and non-routine maintenance; the designation of required inspection items (RII); the methods, standards, and personnel authorized to perform required inspections; reinspection procedures; tool and equipment calibration; procedures ensuring all required inspections are performed; separation of the work function from the inspection function; protection of the required-inspection-item inspector's decision from being overruled by anyone other than supervisory maintenance personnel; and a system ensuring the work is properly performed before the aircraft is released to service.
How FileFlo tracks it
FileFlo indexes the RII list, inspection-method procedures, and the airworthiness-release control procedure against the maintenance manual revision, so the version in force at the time of any maintenance event is reconstructable.
§135.427(c) — Recordkeeping system
14 CFR §135.427(c)What it requires
The manual must describe a system of maintaining records of all work performed on the aircraft, including the name of the person performing the work and, where required, that the work was inspected and the aircraft approved for return to service. The recordkeeping description is distinct from the records themselves — the FAA expects both the documented system and the executed records to match.
How FileFlo tracks it
FileFlo stores and indexes the maintenance records the §135.427(c) system describes, cross-referenced to aircraft and to the §135.443 return-to-service entries, and includes them in the audit binder.
§135.427(d) — Retrievable in English
14 CFR §135.427(d)What it requires
The maintenance information and instructions must be in printed form, or another form acceptable to the Administrator, that is retrievable in the English language. This mirrors the §135.21(g) standard for the operations side of the manual: an electronic manual is permitted, but only if it meets the clear-display-and-retrievability bar.
How FileFlo tracks it
FileFlo keeps every maintenance manual revision retrievable and version-locked, so the controlling English-language text for any date is producible on demand.
Contract maintenance does not eliminate the manual obligation
An operator that contracts all of its maintenance to a Part 145 repair station may not maintain a separate, detailed General Maintenance Manual of its own — but the operations manual must still describe the maintenance arrangement, identify the program the aircraft is maintained under, and reference the contracted persons. The §135.427(a) list of persons with whom maintenance is arranged applies whether the work is in-house or contracted out.
The cleanest way to think about it: §135.425 establishes that the operator has a maintenance and inspection program; §135.427 requires the operator to write that program into the manual; and the executed maintenance records (airworthiness directives, return-to-service entries, inspection sign-offs) prove the program was followed. For the records side, see AD compliance records, §43.9 maintenance entries, and CAMP recordkeeping.
FileFlo is the proof layer, not the manual-authoring or maintenance-tracking system
FileFlo is a compliance document intelligence platform — it classifies, indexes, version-locks, and tracks the distribution and expiration of your manual revisions and the records that prove the manual was followed. It is not a manual-authoring tool, a maintenance-tracking system, a dispatch or flight operations management system, or your safety program. It sits alongside those systems and keeps the documentary record audit-ready. We do not run your operation; we make the paper that proves it provable.
Could you produce the current — and the prior — manual revision in 60 seconds?
FileFlo classifies and version-locks every GOM and General Maintenance Manual revision, tracks who has acknowledged the current one, and reconstructs the controlling text for any past date — organized for a one-click POI surveillance binder. Starter at $89/mo, Professional at $299/mo. 5-day free trial, no credit card required.
Currency, Distribution, and Acknowledgment
The content requirements get the attention, but the control requirements in §135.21 — keeping the manual current, distributing it to the right people, and ensuring they incorporate the changes — are where most surveillance findings actually originate. Here is what the rule requires, paragraph by paragraph.
Keep it current — §135.21(a)
The manual must be kept current. There is no fixed revision cadence in the rule; "current" is event-driven. A regulatory amendment, a change to the operations specifications, a new aircraft type, a change in management personnel under §119.69(a), or a new authorization all create a currency obligation. The operator that revises only on an annual calendar will fall out of currency the first time an operations-specifications amendment lands mid-year.
Do not contradict the operations specifications — §135.21(c)
The manual may not be contrary to any applicable Federal or foreign regulation, the operating certificate, or the operations specifications. This is the substantive currency test: it is not enough to have a recent revision date — the content must actually align with the operator's current authorizations. A GOM that authorizes an operation the operations specifications no longer permit (or omits one they now require) violates §135.21(c) regardless of how recently it was revised.
Distribute to the right people — §135.21(b) and (d)
At least one complete copy must be kept at the principal base of operations (§135.21(b)). A copy, or the appropriate portions, must be made available to maintenance and ground operations personnel, and furnished to (1) flight crewmembers and (2) representatives of the Administrator assigned to the certificate holder (§135.21(d)). "Furnished to" the flight crew is a higher bar than "made available" — the operator must actually put the relevant portions in the crewmember's hands.
Ensure recipients incorporate changes — §135.21(e)
Each employee who is furnished a manual or appropriate portions under §135.21(d)(1) must keep it up to date with the changes and additions furnished to them. This places an affirmative duty on each recipient — and, in practice, an affirmative tracking duty on the operator to know that the duty was met. A revision sent by email that a crewmember never opened is the textbook §135.21(e) failure.
Keep the right parts accessible during duty — §135.21(f)
The operator must ensure the appropriate parts of the manual are accessible to flight, ground, and maintenance personnel at all times when they are performing their assigned duties. Note this is an accessibility standard tied to duty performance — not a blanket requirement to carry the entire manual aboard every aircraft. Specific documents (such as operating information under §135.83) have their own carriage rules.
Display clearly and retrievable in English — §135.21(g)
The information and instructions in the manual must be displayed clearly and be retrievable in the English language. Electronic manuals are permitted, but the retrievability and clarity standard governs the format — a PDF buried in a shared drive that staff cannot reliably find may satisfy the letter of "electronic" while failing the "retrievable" standard.
The acknowledgment gap is the failure paper systems cannot close
A Word document on a network drive can be revised. An email can distribute it. What neither does reliably is prove, two revision cycles later, that every required recipient incorporated every change under §135.21(e) — which is precisely what a Principal Operations Inspector samples during surveillance. The distribution-and-acknowledgment record is the part that degrades fastest and is the most expensive to reconstruct after the fact.
For how this fits the broader surveillance picture, see how to prepare for a Part 135 FAA surveillance audit and the FAA Part 135 SMS 2027 deadline, which adds a safety-management-system manual to the document set every Part 135 operator must maintain by May 28, 2027.
Surveillance Reality: What the POI Actually Checks
During a Part 135 surveillance visit, the manual is rarely examined in isolation. The Principal Operations Inspector pulls the current manual, then tests it against three things: the operator's operations specifications (does the manual contradict them, violating §135.21(c)?), the distribution and acknowledgment record (was the current revision actually furnished and incorporated under §135.21(d) and (e)?), and the operational records (do flight locating, mechanical-irregularity, and recordkeeping records match the procedures the §135.23 manual sections describe?).
A manual file that survives surveillance
Current controlling revision
The in-force GOM and General Maintenance Manual, uniquely identified by revision number and effective date, with no conflict against the current operations specifications (§135.21(a), (c))
Revision history
Every prior revision retrievable, so the controlling text on the date of any past flight or maintenance event can be reconstructed
Operations-specifications alignment
Each manual section that restates or extracts an operations-specifications authorization mapped to the current operations specifications, with every amendment reflected (§135.23(c))
Distribution record
Evidence the current revision, or the appropriate portions, was furnished to each flight crewmember and made available to ground and maintenance personnel (§135.21(d))
Acknowledgment record
Evidence each required recipient incorporated the changes into their copy (§135.21(e)) — the part most likely to be sampled and most likely to be missing
Maintenance manual content
For operators that maintain their own aircraft, the §135.423 organization chart, §135.425 programs, contracted-persons list, and recordkeeping system written into the manual (§135.427(a)–(c))
Records that match the procedures
Flight locating, mechanical-irregularity, and maintenance records that reflect the procedures the manual actually prescribes — proving the manual is followed, not just written
The operator that can produce all seven — immediately, for any past date, without an all-hands document hunt — is in a fundamentally different posture than one that cannot. The gap between those two positions is almost entirely a document-management problem. The procedures exist. The work was done. The question the surveillance visit asks is whether the manual file proves it.
Enforcement of manual deficiencies runs through the FAA's compliance program; where a case proceeds to enforcement action, civil penalties under 49 U.S.C. § 46301 reach $75,000 per violation (14 CFR §13.301; violations on or after December 30, 2024), and systemic or repeated findings can support certificate action under 49 U.S.C. § 44709. Because the manual is the framework for nearly every authorized operation, manual findings are rarely isolated — which is exactly why keeping the manual current, distributed, and acknowledged is among the highest-leverage compliance tasks a Part 135 operator has.
For adjacent manual and record obligations, see the Part 135 drug and alcohol program records checklist, Part 91 aircraft records, and Part 91K fractional-ownership compliance records.
Frequently Asked Questions
Does a Part 135 operator have to have a General Operations Manual?
Yes — with one narrow exception. Under 14 CFR §135.21(a), each certificate holder, other than one who uses only one pilot in its operations, must prepare and keep current a manual setting forth the certificate holder's procedures and policies acceptable to the Administrator. A true single-pilot operator is exempted from the manual requirement, and the Administrator may authorize a deviation for a limited-size operation if all or part of the manual is not necessary for the guidance of flight, ground, or maintenance personnel. Every other Part 135 operator must have the manual, keep it current, and make it available as §135.21 requires. The manual the industry calls the General Operations Manual (GOM) is the document that satisfies §135.21, and its required contents are set out in §135.23.
What is the difference between the General Operations Manual and the General Maintenance Manual?
The CFR does not formally use the trade terms "General Operations Manual" or "General Maintenance Manual" — those are industry conventions. The single manual required by 14 CFR §135.21 with contents specified in §135.23 is what operators call the General Operations Manual (GOM). Separately, when a certificate holder maintains aircraft under its own continuous airworthiness or approved aircraft inspection program, 14 CFR §135.427 requires it to put in its manual the organizational chart required by §135.423 and the maintenance, preventive maintenance, and alteration programs required by §135.425 — the portion the industry calls the General Maintenance Manual (GMM) or Maintenance Operations Manual. In practice many operators keep two physically separate volumes (a GOM and a GMM) so the operations and maintenance staff each carry the part relevant to their duties, but both are legally "the manual" under §135.21 and §135.21(c) requires neither to contradict the operator's operations specifications.
What must the General Operations Manual contain under §135.23?
14 CFR §135.23 lists the required contents. Among them: the name of each person authorized to act for the certificate holder in management positions under §119.69(a) (Director of Operations, Chief Pilot, Director of Maintenance) with their areas of responsibility, and the names of persons authorized to exercise operational control under §135.77 (§135.23(a)); weight-and-balance procedures (§135.23(b)); enough of the operations specifications to provide guidance to personnel (§135.23(c)); accident-notification procedures (§135.23(d)); airworthiness-inspection and return-to-service confirmation procedures for pilots (§135.23(e)); mechanical-irregularity reporting and recording procedures (§135.23(f)); procedures for the pilot to determine prior defects were corrected or deferred (§135.23(g)); procedures for obtaining maintenance and servicing away from base (§135.23(h)); inoperative-equipment release procedures (§135.23(i)); refueling and fire-safety procedures (§135.23(j)); passenger-briefing procedures (§135.23(k)); flight-locating procedures where applicable (§135.23(l)); emergency-procedure assignments (§135.23(m)); en route pilot qualification procedures where applicable (§135.23(n)); approved aircraft inspection programs where applicable (§135.23(o)); hazardous-materials handling procedures (§135.23(p)); evacuation procedures for persons needing assistance (§135.23(q)); destination-airport analysis where required by §135.385 (§135.23(r)); and other procedures and policy instructions the Administrator requires (§135.23(s)).
Who must receive a copy of the Part 135 manual?
Under 14 CFR §135.21(d), a copy of the manual, or the appropriate portions of it (and the changes and additions), must be made available to maintenance and ground operations personnel and must be furnished to (1) the operator's flight crewmembers and (2) representatives of the Administrator assigned to the certificate holder. Section 135.21(b) requires the operator to keep at least one complete copy of the manual at its principal base of operations. Section 135.21(e) puts the burden on each employee who receives a manual to keep it up to date with the changes and additions furnished to them, and §135.21(f) requires the operator to ensure the appropriate parts of the manual are accessible to flight, ground, and maintenance personnel at all times when they are performing their assigned duties. The chain of distribution and acknowledgment is exactly where paper systems break: a revision is issued at base but never actually reaches every crewmember's current copy.
Does the manual have to be in English or carried aboard the aircraft?
Under 14 CFR §135.21(g), the information and instructions in the manual must be displayed clearly and be retrievable in the English language. The manual itself may be in paper or electronic form so long as it meets that retrievability standard. As for carriage, §135.21 does not, by its own terms, require the entire manual to be carried aboard every aircraft — what it requires is that the appropriate parts be accessible to personnel performing their duties (§135.21(f)) and that a complete copy be kept at the principal base of operations (§135.21(b)). Separate sections of Part 135 do require specific documents aboard the aircraft (for example, operating information under §135.83), but the manual-carriage question is governed by the "appropriate parts accessible when performing assigned duties" standard rather than a blanket "carry the whole GOM on every flight" rule.
What does §135.427 require the General Maintenance Manual to contain?
Under 14 CFR §135.427(a), a certificate holder that maintains aircraft under Part 135 must put in its manual the chart or description of its organization required by §135.423 and a list of the persons with whom it has arranged for the performance of any required inspections, other maintenance, preventive maintenance, or alterations, with a general description of that work. Section 135.427(b) requires the operator to put in the manual the programs required by §135.425 that must be followed in performing maintenance — including the method of performing routine and non-routine maintenance, the designation of required inspection items (RII), the methods and personnel authorized to perform required inspections, reinspection procedures, the standards and tool-calibration procedures, procedures to ensure all required inspections are performed, work-and-inspection separation, protection of the inspector's decision from override, and a system to ensure work is properly performed before the aircraft is released to service. Section 135.427(c) requires a system of recordkeeping for work performed, and §135.427(d) requires that the maintenance information be retrievable in the English language. The underlying maintenance program itself is established by §135.425.
How must the manual be kept current, and why does that drive FAA findings?
Section 135.21(a) requires the manual to be kept current, and §135.21(c) requires that it not be contrary to any applicable Federal or foreign regulation, the certificate holder's operating certificate, or its operations specifications. That means every time the operator's operations specifications change, an aircraft type is added, a new authorization is granted, or a regulation is amended, the manual must be revised so it does not contradict the new authority. Section 135.21(e) then requires each recipient to incorporate the changes into their copy. The most common surveillance finding is not a poorly written manual — it is a manual revision that was issued but never distributed to every required recipient under §135.21(d), never acknowledged or incorporated under §135.21(e), or that now contradicts the current operations specifications in violation of §135.21(c). Because the manual is the framework for nearly every operational procedure the certificate authorizes, one stale revision can cascade into downstream findings across flight locating, mechanical-irregularity reporting, and recordkeeping.
What FAA civil penalty applies to manual violations?
Manual deficiencies under §135.21, §135.23, or §135.427 are dispositioned through the FAA's compliance program, and where enforcement action is pursued, civil penalties under 49 U.S.C. § 46301 reach $75,000 per violation (14 CFR §13.301, adjusted periodically under the Federal Civil Penalties Inflation Adjustment Act). Manual findings tend to be treated as systemic because the manual is the procedural backbone of the certificate — a single missing or stale revision can implicate every record created under the procedure it governs. Systemic or repeated manual findings can also support certificate action under 49 U.S.C. § 44709. The asymmetry is the point: the cost of keeping the manual current, distributed, and acknowledged is trivial next to the cost of reconstructing the distribution-and-acknowledgment trail during a surveillance visit, or defending an enforcement case built on a manual that contradicted the operations specifications.
Keep your GOM and General Maintenance Manual audit-ready — every revision, every recipient
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Reviewed by Chad Griffith, Founder, FileFlo — compliance document intelligence — June 9, 2026. Regulatory citations verified against the Cornell Legal Information Institute (14 CFR §135.21, §135.23, §135.425, §135.427, §119.69) as of publication date. This article is educational and is not legal advice.