The ACSF Industry Audit Standard (IAS): A Plain-English Guide for Part 135 & 91K Operators

Last reviewed June 16, 2026 · By Chad Griffith

The ACSF Industry Audit Standard (IAS) is a voluntary third-party audit, run by the nonprofit Air Charter Safety Foundation, that evaluates a Part 135, 91K, or Part 91 operator's regulatory compliance and Safety Management System against 14 CFR Part 5 and ICAO Annex 19. It is conducted every 24 months.

What is the ACSF Industry Audit Standard (IAS)?

The ACSF Industry Audit Standard (IAS) is a comprehensive, voluntary safety audit administered by the Air Charter Safety Foundation (ACSF), a nonprofit organization. It is one of four widely recognized charter audit standards in business aviation, alongside ARGUS, Wyvern, and IS-BAO. The IAS was the first audit program built specifically for on-demand operators, developed by a committee of Part 135 and 91K industry leaders, and its operational requirements are drawn largely from best practices used in the FAR Part 121 (airline) community and applied to the charter and fractional marketplace. It is not an FAA regulation or certification; it is an industry standard that operators pursue to demonstrate safety maturity beyond minimum legal compliance.

Who is the IAS for, and is it required?

The IAS is designed for three operator types: Part 135 on-demand charter operators, Part 91K fractional ownership program managers, and Part 91 corporate flight departments. It is entirely voluntary, no FAA rule requires it. Operators pursue it because charter brokers, fractional buyers, corporate flight departments, and aviation insurers increasingly treat a current third-party audit as a precondition for doing business, and an IAS listing on the public ACSF registry (available free at acsf.aero/registry) gives those buyers an independent signal of safety and compliance. In practice the IAS functions as a market gate rather than a legal one: passing it does not change your operating certificate, but failing to hold a recognized audit can quietly cut you out of broker and insurer pipelines.

What does an IAS auditor actually review?

The IAS is a detailed gap analysis of an operator's management practices, evaluating both regulatory compliance and the operator's Safety Management System (SMS) against FAA standards (notably 14 CFR Part 5) and international standards (ICAO Annex 19). Before the on-site audit, the operator must prepare a defined documentation package, which includes an Operator Standards Manual and supporting guidance appendices, and complete a required Pre-Audit Self-Assessment Checklist as a prerequisite. The auditor then verifies that the manuals, SMS components, training and currency records, maintenance and airworthiness documentation, and operational procedures actually exist, are current, and match what the operator claims on paper. The audit is records-intensive: a large share of the effort is producing, organizing, and proving the document trail behind every requirement.

How the IAS compares to ARGUS, Wyvern, and IS-BAO

All four are voluntary third-party programs valued by brokers and insurers, but they differ in origin and emphasis. ARGUS International is the most widely recognized name and tiers operators from Gold (a historical-records desk review of pilot, maintenance, FAA-compliance, and insurance data) up to Platinum (an on-site audit). Wyvern, the original business-aviation auditor founded in 1991, distinguishes a Registered data-submission tier from its in-depth Wingman certification with biennial reassessments. IS-BAO, administered by IBAC, is the international SMS-centered standard organized in three progressive stages. The ACSF IAS is the nonprofit, committee-built standard for U.S. on-demand and fractional operators, conducted every 24 months and explicitly aligned to 14 CFR Part 5 and ICAO Annex 19. Notably, ACSF and Wyvern collaborate so an operator can complete a single combined audit that satisfies both the ACSF IAS and the Wyvern Wingman standard, two results from one audit. The common thread across all four is the same underlying demand: a current, organized, provable records package.

The ACSF Aviation Safety Action Program (ASAP)

Beyond the audit standard, the ACSF also administers an industry-managed Aviation Safety Action Program (ASAP). An ASAP is a voluntary, non-punitive safety-reporting program in which employees report safety concerns and a review process analyzes de-identified data to catch hazards before they cause an accident. The ACSF positions its program as delivering the benefits of the FAA's voluntary ASAP, typically at a lower cost than each operator standing up its own. In 2024 the ACSF ASAP recorded 888 submitted events from 281 active participants, reflecting a growing industry emphasis on open reporting and transparent safety-data analysis. ASAP participation is separate from the IAS audit, but both feed the same safety-culture story that brokers and insurers want to see.

Where records readiness breaks down, and how FileFlo fits

For most operators the hard part of the IAS is not the flying or even the SMS philosophy, it is the document package. Auditors fail or down-grade operators on missing, expired, or unverifiable records far more often than on operational deficiencies, and assembling the Operator Standards Manual evidence and Pre-Audit Self-Assessment proof by hand is slow and error-prone. FileFlo is the records-readiness layer for that work. It classifies each compliance document to its specific CFR citation, tracks expiration dates so nothing lapses before the auditor arrives, flags missing records against the requirements you should hold, and exports an inspector-ready, auditor-ready records binder on demand. FileFlo is deliberately not your SMS, not the auditor, and not an operations or scheduling system, it is the proof layer that makes the document side of an IAS, ARGUS, Wyvern, or IS-BAO audit, or an FAA inspection, fast to assemble and easy to defend. Plans are $89 and $299 per month with a 5-day trial.

How to prepare for an IAS audit

Preparation comes down to closing the gap between what your manuals say and what your files can prove. Start by completing the ACSF Pre-Audit Self-Assessment Checklist honestly and treating every 'should have' as a records task. Confirm your Operator Standards Manual and SMS documentation reflect current 14 CFR Part 5 and ICAO Annex 19 expectations. Then inventory the underlying evidence, pilot training and currency, medicals, airman certificates, maintenance and airworthiness records, drug and alcohol program documentation, and insurance, and verify each item is present, current, and matches the manual. Catch expirations before the audit window, not during it. Operators that keep this evidence continuously organized, rather than scrambling in the weeks before the auditor arrives, pass more cleanly and renew on the 24-month cycle with far less effort.

← Back to Aviation Compliance Guide