13 records
How often does this aircraft inspection or test have to be done?
13 records, one fact each. Every value is transcribed from the source that states it and carries the sentence it was taken from: 5 sources across 1 site, last checked 2026-08-06, due for re-check by 2028-08-05. Every record is listed below, each linking the page its value came from.
About this data
How often each required aircraft inspection, test or check must be done under Part 91, in the unit the regulation actually uses. Each record is one item with its interval, the anchor the interval runs from, and the consequence of letting it lapse. Covers the annual and 100-hour inspection (14 CFR 91.409), the altimeter and static pressure system test (91.411), the ATC transponder test (91.413), the emergency locator transmitter inspection and battery replacement (91.207), and the VOR equipment check for IFR (91.171). Answers 'does an ELT battery have to be replaced every year', 'how often does a transponder need to be checked', 'is the pitot static check 24 months', 'does a 100 hour inspection reset the annual', and 'how often do I need a VOR check for IFR'. Every one of these is expressed in a different unit - 12 calendar months, 100 hours, 24 calendar months, 30 days, 1 cumulative hour of transmitter use or 50 percent of useful life - which is why the neighbouring ones get swapped: the ELT 12-month item is the inspection, not the battery.
The data
| Inspection or test item | Interval | Applies to | Consequence if lapsed | Regulation section |
|---|---|---|---|---|
| 100-hour inspection | within the preceding 100 hours of time in service | aircraft carrying any person (other than a crewmember) for hire | no person may operate an aircraft carrying any person (other than a crewmember) for hire | § 91.409 |
| Altimeter instrument | Within the preceding 24 calendar months | airplane, or helicopter, in controlled airspace under IFR | No person may operate an airplane, or helicopter, in controlled airspace under IFR | § 91.411 |
| Annual inspection | within the preceding 12 calendar months | aircraft | no person may operate an aircraft | § 91.409 |
| ATC transponder | within the preceding 24 calendar months | ATC transponder that is specified in 91.215(a), 121.345(c), or § 135.143(c) of this chapter | No persons may use an ATC transponder | § 91.413 |
| Automatic pressure altitude reporting system | Within the preceding 24 calendar months | airplane, or helicopter, in controlled airspace under IFR | No person may operate an airplane, or helicopter, in controlled airspace under IFR | § 91.411 |
| Batteries used in the emergency locator transmitters | When the transmitter has been in use for more than 1 cumulative hour; or (2) When 50 percent of their useful life (or, for rechargeable batteries, 50 percent of their useful life of charge) has expired | emergency locator transmitters required by paragraphs (a) and (b) of this section | must be replaced (or recharged, if the batteries are rechargeable) | § 91.207 |
| Emergency locator transmitter | within 12 calendar months after the last inspection | Each emergency locator transmitter required by paragraph (a) of this section | must be inspected within 12 calendar months after the last inspection | § 91.207 |
| Installation or maintenance on an ATC transponder | Following any installation or maintenance on an ATC transponder where data correspondence error could be introduced | ATC transponder where data correspondence error could be introduced | No persons may use an ATC transponder | § 91.413 |
| Installation or maintenance on the automatic pressure altitude reporting system of the ATC transponder | Following installation or maintenance on the automatic pressure altitude reporting system of the ATC transponder | airplane, or helicopter, in controlled airspace under IFR | No person may operate an airplane, or helicopter, in controlled airspace under IFR | § 91.411 |
| Opening and closing of the static pressure system | following any opening and closing of the static pressure system | airplane, or helicopter, in controlled airspace under IFR | No person may operate an airplane, or helicopter, in controlled airspace under IFR | § 91.411 |
| Progressive inspection | within each 12 calendar months | aircraft | § 91.409 | |
| Static pressure system | Within the preceding 24 calendar months | airplane, or helicopter, in controlled airspace under IFR | No person may operate an airplane, or helicopter, in controlled airspace under IFR | § 91.411 |
| VOR equipment | within the preceding 30 days | civil aircraft under IFR using the VOR system of radio navigation | No person may operate a civil aircraft under IFR | § 91.171 |
Where this came from
Every record above links the page it was taken from and quotes the sentence that states it. These are the 5 sources this dataset was assembled from.
- ecfr.govhttps://www.ecfr.gov/api/versioner/v1/full/2026-08-01/title-14.xml?part=91§ion=91.409
- ecfr.govhttps://www.ecfr.gov/api/versioner/v1/full/2026-08-01/title-14.xml?part=91§ion=91.411
- ecfr.govhttps://www.ecfr.gov/api/versioner/v1/full/2026-08-01/title-14.xml?part=91§ion=91.413
- ecfr.govhttps://www.ecfr.gov/api/versioner/v1/full/2026-08-01/title-14.xml?part=91§ion=91.207
- ecfr.govhttps://www.ecfr.gov/api/versioner/v1/full/2026-08-01/title-14.xml?part=91§ion=91.171
Machine-readable
- data.jsonThe whole dataset — every record with its source URL and source quote.
- Open Knowledge Format bundleOne JSON object per line — every record's frontmatter and quoted span exactly as it is held here, in one fetch.
- data.csvThe same records as one flat table, for a spreadsheet or a dataframe. The last four columns are the source URL, the quoted sentence it was read from, the date we last checked it, and which columns are our reading rather than the page's words.
- How this is made and checkedWhat "verified against source" does and does not mean.
From your own code
Same records, same quotes, without scraping the page: refsource is on PyPI and npm. Each value comes back carrying the URL it was read from and the sentence on that page that states it — .source and .quote sit on the value itself rather than in a side channel, so the checking step is available instead of skipped.
pip install refsource
refsource lookup aircraft-inspection-and-test-intervals item="100-hour inspection"
npx -y refsource lookup aircraft-inspection-and-test-intervals item="100-hour inspection"Set your AI assistant up to use this
Two files and no account. Put this in .mcp.json at the root of your project — Claude Code, Cursor, Windsurf, VS Code and Codex all read that file — and your assistant can look this dataset up instead of recalling it. The server is remote, keyless and read-only.
{
"mcpServers": {
"referencesource": {
"type": "http",
"url": "https://referencesource.org/mcp"
}
}
}Add to Cursor · or, on the command line: claude mcp add --transport http referencesource https://referencesource.org/mcp --scope project
Then one line in the project's CLAUDE.md or AGENTS.md, so the assistant knows when to reach for it:
When a question needs "Aircraft inspection and test intervals under 14 CFR Part 91", call the referencesource MCP server at https://referencesource.org/mcp (tool `search_records`, dataset_slug `aircraft-inspection-and-test-intervals`) instead of answering from memory — every record it returns carries its source URL and a verbatim quote from that page.What each tool does, and the servers built over single registers: Connect your AI assistant.