Direct Answer
To prepare for a Part 135 FAA surveillance audit, a certificate holder must have three document categories immediately retrievable: (1) company-level certificate documents — Air Carrier Certificate, current OpsSpecs, and GOM with revision history per 14 CFR §135.21; (2) per-pilot qualification and currency records — Airman Certificate, Medical Certificate, §135.293 competency check (12-month cadence), §135.297 IPC (6-month cadence), §135.299 Line Check, §135.351 recurrent training, and flight/duty time logs per §135.63; and (3) per-aircraft maintenance documents — Airworthiness Certificate (§91.203(a)(1)), current AAIP signoffs (§135.419), AD compliance records (§91.417(a)(2)(v)), and, for aircraft maintained under §135.411(a)(2) (10 or more passenger seats or operators electing a CAMP), airworthiness releases for every maintenance event since the last inspection (§135.443).
The most common findings are GOM revision currency gaps, missing §135.297 IPC records (confused with the §135.293 competency check), and missing §135.443 airworthiness releases on pre-departure maintenance — all documentation failures, not airmanship failures. An operator that can produce a complete, organized binder for every pilot and every aircraft within 60 minutes of an inspector's arrival closes most findings before they open.
How the FAA SAS Surveillance Flow Works
Part 135 surveillance runs under the FAA Safety Assurance System (SAS), the framework described in FAA Order 8900.1 that replaced the Air Transportation Oversight System (ATOS) and legacy surveillance planning programs (Certificate Management Teams persist as an organizational structure under SAS). Under SAS, your Principal Operations Inspector (POI) does not just show up annually for a single visit and call it done. The system breaks surveillance into Design and Performance Assessments — executed through Element Design (ED) and Element Performance (EP) Data Collection Tools across the operations, airworthiness, training, and hazardous materials domains — that can be triggered annually or by specific events (accidents, incidents, significant fleet changes, key personnel turnover, or OpSpec amendments).
The practical consequence for a Part 135 operator: you are always potentially in a surveillance window. An event-driven assessment triggered by a runway incursion or a pilot change is structurally identical to the scheduled annual visit — the inspector pulls the same document categories. The operators who consistently pass surveillance clean are the ones who treat the binder as a living system, not a pre-audit assembly project.
POI initiates the surveillance event
Either on the scheduled annual cycle or triggered by an event (accident, incident, certificate amendment, key personnel change). The operator may or may not receive advance notice depending on the type of assessment.
Certificate and program documents requested first
The POI starts by verifying the certificate holder is authorized to conduct the operations in question: Air Carrier Certificate, OpsSpecs, and GOM currency. A GOM out of revision sync with the approved program is a finding before the pilot files even open.
Per-pilot records reviewed against CFR currency windows
Each active pilot's training and qualification file is pulled. The POI verifies §135.293 (12-month), §135.297 IPC (6-month), §135.299 line check (12-month), and §135.351 recurrent training independently. Medical class is verified against the operation type under §135.243.
Aircraft maintenance documentation reviewed
For each aircraft on the certificate, the PMI (Principal Maintenance Inspector) or POI verifies Airworthiness Certificate, current AAIP signoffs or 91.409 inspection records, AD compliance status, and — for aircraft maintained under §135.411(a)(2) (10+ passenger seats or a CAMP election) — §135.443 airworthiness releases for every maintenance event since the prior inspection.
Findings documented; corrective action tracking begins
Each finding is documented in SAS with a corrective action plan deadline. Systemic findings or repeat findings from prior surveillance can escalate to certificate action under 14 CFR Part 13.
Surveillance findings are documentation problems — not airmanship problems
The most common Part 135 surveillance findings are administrative: a GOM revision not distributed to all crew, a §135.297 IPC expired by one month, or a §135.443 airworthiness release missing from a pre-departure squawk fix. None of these reflect unsafe flying — they reflect a document management gap. The right system prevents them structurally before the inspector arrives.
The Part 135 SAS Surveillance Document Checklist
Every document below is a real POI request, sourced from 14 CFR Part 135, 14 CFR Part 91, and FAA Order 8900.1 SAS. Orange callouts flag the most common findings in that category.
Certificate & Operations Specifications
14 CFR Part 119; §135.21The POI opens with these documents to confirm the operator is authorized to fly at all and that the program governing its operations is current.
Air Carrier Certificate
Common finding: Missing or unamended after fleet/ops change is an immediate certificate action.
Operations Specifications (OpsSpecs)
General Operations Manual (GOM) — current revision
Common finding: Stale revision or missing distribution signoffs is among the top-5 Part 135 surveillance findings.
General Maintenance Manual (GMM) — current revision
Director of Operations / Chief Pilot / Director of Maintenance designation letters
Drug and Alcohol Testing Program plan + MIS report (when required)
Per-Pilot Qualification & Currency Records
14 CFR §135.63, §135.243, §135.293, §135.297, §135.299The POI pulls every active pilot file and verifies training and check currency against the CFR calendar-month windows. Gaps here produce the majority of per-pilot findings.
Airman Certificate — correct category, class, type rating
Common finding: Wrong certificate class for the operation is an immediate grounding finding.
Medical Certificate — class verified against ops type
Common finding: Expired medical is an immediate grounding finding. 1st class vs. 2nd class mismatch for ops type is a separate finding.
§135.293 Competency Check record (written/oral + practical)
Common finding: Most-cited recurring pilot training finding. Confusing this with §135.297 (different cadence) is common.
§135.297 Instrument Proficiency Check (IPC)
Common finding: Separate from §135.293. A current competency check does NOT satisfy the IPC requirement.
§135.299 Line Check record
§135.351 Recurrent Training record (ground + flight)
Initial / Transition / Differences Training records
Operating Experience (IOE) record — §135.244 (commuter operations only)
Recent Flight Experience — §135.247
Flight time / duty time logs
Drug & Alcohol test records — all test types
Pilot Records Improvement Act (PRIA) records
Per-Aircraft Airworthiness & Maintenance Documents
14 CFR §91.203, §91.417, §135.419, §135.443The POI or Principal Maintenance Inspector (PMI) verifies these documents for each aircraft operating on the certificate. Missing airworthiness releases on routine pre-departure maintenance are among the most common findings in this category.
Airworthiness Certificate (FAA Form 8100-2)
Common finding: Not displayed or not on board is an immediate finding.
Aircraft Registration Certificate (AC Form 8050-3)
Minimum Equipment List (MEL) — per aircraft type
AAIP — Approved Aircraft Inspection Program (or 91.409 inspection records if no AAIP)
Common finding: Many operators do not know which inspection regime governs each aircraft — AAIP vs. annual creates conflicting records.
Aircraft / Engine / Propeller logbooks
Airworthiness Directive (AD) compliance record
Airworthiness Release / maintenance log entry (per maintenance event)
Common finding: Missing releases on pre-departure squawk corrections are among the top aircraft maintenance findings.
Weight and Balance documentation
Transponder test and inspection record
Altimeter system and altitude reporting equipment test
ELT inspection record
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Run the Free FAA Readiness ScoreThe 6 Most Common Part 135 Surveillance Findings
These findings appear repeatedly across Part 135 surveillance visits under the SAS framework. None involve unsafe flying — all trace directly to document management failures that a well-structured compliance system prevents.
The General Operations Manual must be kept current and must be available at the principal base of operations. POIs verify both that the revision itself is current with FAA-approved content and that revision distribution records show all applicable crew received and acknowledged the change. A manual that was revised but not distributed to dispatchers or check airmen produces a finding even if the content is correct.
The Instrument Proficiency Check has a 6-month cadence — half the 12-month window for the §135.293 competency check. Many operators track the competency check carefully and let the IPC slip. A pilot with a current §135.293 check but an expired §135.297 IPC cannot legally serve as PIC under IFR. This is among the most common per-pilot findings in scheduled surveillance.
For aircraft maintained under §135.411(a)(2) — 10 or more passenger seats, or operators electing a CAMP — any maintenance, preventive maintenance, or alteration requires a §135.443 airworthiness release or maintenance log entry before the aircraft returns to service. High-utilization operators fixing pre-departure squawks — replacing a burned-out reading light, correcting a minor instrument discrepancy — routinely fail to generate the corresponding §135.443 entry. Over a year of operations, this can produce dozens of individual findings from a single POI inspection.
Under §135.243, the pilot certificate and medical class requirements differ depending on whether the operation involves a turbojet aircraft, an aircraft with 10 or more passenger seats, a scheduled commuter route, or VFR/IFR commercial operations. A pilot flying a turbojet on charter who holds a Second Class medical (valid for commercial, but not for ATP operations required by §135.243(a)) is a compliance gap. First Class medical expiry also varies by age — 12 months under 40, 6 months at 40 and over for ATP operations.
Aircraft operated under an Approved Aircraft Inspection Program (AAIP) are exempt from the standard annual and 100-hour inspections under §91.409(c)(2). Operators with mixed fleets — some aircraft on AAIP, some not — sometimes maintain the wrong inspection type for a given tail. The POI will ask for each aircraft's governing inspection program and verify the most recent signoff matches that program.
Airworthiness Directive compliance records must document both applicability (which ADs apply to this specific airframe/engine/propeller serial number) and compliance (the method of compliance, AD number and revision date, and the next action due date for recurring ADs). An operator who can show the AD was completed but lacks the corresponding §91.417(a)(2)(v) log entry is in the same position as one who cannot show compliance at all — the record, not just the work, is the requirement.
Building a Retrievable Audit Binder Before the Inspector Arrives
The goal of audit preparation is not memorizing the CFR — it is making every required document retrievable in the order the POI requests it. An inspector who waits 45 minutes while a director of operations assembles a pilot file that should already exist as a complete package is already forming a negative impression before a single finding is documented.
Organize by the POI's workflow, not by pilot or aircraft
Structure the binder in three sections matching the three document domains: (1) Company/Certificate, (2) Per-Pilot, (3) Per-Aircraft. Within each section, sort by the most time-sensitive documents first — expired records surface faster when they are at the top of the stack.
Surface expiring records before they expire — not after
The most damaging moment in a surveillance visit is when the inspector finds an expired §135.297 IPC that the director of operations did not know was expired. A compliance system that surfaces 90/60/30-day expiration alerts for every training check and medical certificate eliminates this category of finding entirely.
Verify revision currency before every surveillance event
Run a GOM and GMM revision audit at least 30 days before any scheduled surveillance window. Verify that the revision on the shelf matches the FAA-approved revision, and that distribution records show all required recipients received and acknowledged the current version.
Keep a §135.443 release log running at all times
High-utilization operators should maintain a rolling airworthiness release log tied to each aircraft. Every pre-departure maintenance action — even minor — generates an entry. A complete log eliminates the most common aircraft maintenance finding in Part 135 surveillance.
FileFlo: the proof layer that makes the binder retrievable in seconds
FileFlo is a compliance document intelligence platform — a read-only proof layer that sits alongside your existing stack (flight scheduling, maintenance tracking, training software) and organizes the documents those systems produce into a surveillance-ready binder. It does not replace your safety management system, dispatch software, or maintenance tracking platform. It classifies over 600 document types against the governing CFR, tracks expiration windows on every medical, training check, and equipment inspection, and generates an inspector-format audit binder across all three document domains on demand.
For Part 135 on-demand charter operators specifically, FileFlo tracks the per-pilot training matrix (§135.293, §135.297, §135.299, §135.351, medical class and expiry) across the entire crew roster, surfaces any record approaching its window, and generates the per-pilot compliance summary the POI requests. The binder that takes most operators two days to assemble by hand takes FileFlo 60 seconds.
Related FAA compliance resources
Frequently Asked Questions
What does an FAA Principal Operations Inspector (POI) actually request during a Part 135 surveillance visit?
Per FAA Order 8900.1 (Safety Assurance System), the POI arrives with a structured surveillance checklist covering four document categories. First, company-level certificate documents: the Air Carrier Certificate, current Operations Specifications (OpsSpecs), and the General Operations Manual (GOM) with revision currency verified against 14 CFR §135.21. Second, per-pilot qualification and currency records: Airman Certificates, Medical Certificates (with class verified against 14 CFR §135.243 and 61.23 expiry), 135.293 competency check records (12-month cadence), 135.297 Instrument Proficiency Check records (6-month cadence), 135.299 Line Check records, and recurrent training under §135.351. Third, flight/duty time records per §135.63(a)(4) and §§135.265–273. Fourth, aircraft maintenance documentation: Airworthiness Certificates (91.203(a)(1)), current Airworthiness Releases per §135.443 (for aircraft maintained under §135.411(a)(2) — 10 or more passenger seats or operators electing a CAMP), AAIP or 91.409 inspection signoffs, and AD compliance records per 91.417(a)(2)(v). The most common surveillance findings are GOM revision currency gaps, training record expiration misses, and missing airworthiness release entries — all documentation failures, not airmanship failures.
How often does the FAA conduct Part 135 surveillance visits?
Under the FAA Safety Assurance System (SAS) framework described in FAA Order 8900.1, Part 135 certificate holders receive at minimum an annual surveillance cycle. Newly certificated operators and those with recent findings, accidents, or significant changes (fleet additions, new OpSpec amendments, key personnel changes) typically receive more frequent event-driven surveillance. The POI may also conduct ramp checks and en-route surveillance without advance notice. The annual surveillance cycle is not a single visit — SAS breaks it into multiple Design and Performance Assessments, executed through Element Design (ED) and Element Performance (EP) Data Collection Tools, covering operations, airworthiness, training, and hazmat domains. Operators who think in terms of "one annual visit" rather than "continuous readiness" routinely have documentation ready for one area but not another.
What are the record retention requirements under 14 CFR §135.63?
Under 14 CFR §135.63, Part 135 certificate holders must retain individual pilot qualification records (§135.63(a)(4)) and individual flight attendant records for at least 12 months. Load manifests must be retained at the principal operations base for at least 30 days (§135.63(d)). Aircraft maintenance records follow the dual retention scheme of 14 CFR §91.417(b): routine maintenance entries are retained until the work is repeated or superseded or for 1 year after performance; life-limited parts data, total time, inspection status, and AD compliance status are retained permanently and transferred with the aircraft. For aircraft maintained under a §135.411(a)(2) Continuous Airworthiness Maintenance Program (CAMP), airworthiness releases under §135.443 are maintenance log entries retained under the §135.439 recordkeeping scheme. Drug and alcohol test records under 14 CFR Part 120 follow separate retention: positive results are retained 5 years; negative pre-employment results are retained 1 year.
What is the difference between a §135.293 competency check and a §135.297 instrument proficiency check?
These are two distinct recurring tests with different cadences. Under 14 CFR §135.293, each pilot must pass a written or oral knowledge test and a practical competency check administered by the Administrator or an authorized check pilot every 12 calendar months (or within the grace period of the month before or after per §135.301). The competency check is given by aircraft class for single-engine non-turbojet airplanes, and by aircraft type for helicopters, multiengine airplanes, and turbojet airplanes. Under 14 CFR §135.297, each pilot serving as PIC under IFR must separately pass an instrument proficiency check every 6 calendar months — a shorter window reflecting the currency risk of IFR operations specifically. POIs verify both records independently and will cite a missing IPC even if the competency check is current. Many operators confuse the two, treating a successful §135.293 check as satisfying §135.297. It does not — they are separate requirements with separate records.
What is an Airworthiness Release under 14 CFR §135.443 and when is it required?
Under 14 CFR §135.443, a Part 135 certificate holder may not operate an aircraft maintained under §135.411(a)(2) — aircraft type certificated for 10 or more passenger seats, or smaller aircraft whose operator elects a Continuous Airworthiness Maintenance Program (CAMP) — after maintenance, preventive maintenance, or alteration unless an airworthiness release or maintenance log entry has been prepared and signed by an authorized certificated mechanic or repairman. Aircraft with 9 or fewer passenger seats maintained under §135.411(a)(1) are instead returned to service under 14 CFR Part 43 and §91.407. The release must be made in the aircraft maintenance log and certify that the work was performed in accordance with the requirements of the certificate holder's manual, that all required inspections were completed, that no known condition exists that would make the aircraft unairworthy, and that, so far as the work performed is concerned, the aircraft is in condition for safe operation. POIs specifically look for these entries on pre-flight maintenance actions — missing or incomplete airworthiness releases on routine pre-departure squawk corrections are among the most common §135 surveillance findings. These are per-maintenance-event entries, not periodic forms, meaning a high-utilization operator may generate dozens of release entries per month that all need to be retrievable on demand.
Do Part 135 operators need an Approved Aircraft Inspection Program (AAIP) or do annual and 100-hour inspections apply?
Many Part 135 operators that conduct commercial passenger operations operate under an Approved Aircraft Inspection Program (AAIP) per 14 CFR §135.419, which replaces the standard annual inspection (§91.409(a)) and 100-hour inspection (§91.409(b)) requirements for those aircraft. Under §91.409(c)(2), aircraft maintained under an AAIP approved under 14 CFR Part 125 or Part 135 are exempt from the annual and 100-hour inspection requirements. The AAIP itself — the program document, the current aircraft inspection signoffs, and the AAIP revision history — is then a primary surveillance document. Operators that mistakenly maintain annual inspection currency rather than AAIP compliance, or vice versa, create audit findings. The POI will verify which program governs each aircraft in the fleet and request the corresponding records.
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