Timeline — unexplained aerial sightings, worldwide

Chronological spine for the archive. Coordinates in data/notable-cases.csv. Credibility ratings and full case files are in cases/.

2026-09-21 additions (NHI-sighting gap fill)

Gap-filling additions (Task 9), sourced to PURSUE releases and secondary compilations rather than notable-cases.csv:

2026-09-23 additions (institutional gap fill)

Twenty-two rows added to data/timeline-events.csv, each carrying its own source_url. The institutions track was previously entirely United States; every foreign body below was already documented in 02-agencies-and-official-bodies.md but had no row of its own, and the modern US offices — UAPTF, ODNI's assessment, AOIMSG, AARO, NASA's study — were missing outright. Four sightings fill the 1948 and 1993–2006 gaps.

Named flaps

Authored wave brackets in data/timeline-waves.csv — a wave's extent is sourced independently of its member events, so the bracket does not move as research is added:

• WAVE-01, Jul 1952 — the Washington National Airport radar weekend and the month around it.
• WAVE-02, 10–24 Sep 1954 — the French wave, opening with Quarouble; bounded to the dates this project could verify (contemporary tallies run into October, but a firm end date is not sourced here, so the bracket stops at Aimé Michel's last-dated tally rather than a month-end guess).
• WAVE-03, 2–3 Nov 1957 — the Levelland sequence.
• WAVE-04, Oct 1973 — the October 1973 flap, concentrated in the US South (Louisiana and Mississippi); Pascagoula is its best-documented single case.
• WAVE-05, 29 Nov 1989 – Apr 1990 — the Belgian wave.
• WAVE-06, 13 Mar 1997 — the Phoenix Lights. Sourcing supports a single well-documented evening, not the two-year "1996–97 sequence" sometimes claimed; this project did not find a corroborated 1996 precursor and did not invent one.

The basis column, both tracks

basis is a column on every row in data/timeline-events.csv, sightings and institutions alike, and it describes what kind of evidence stands behind a row, not how true the row is or how strong the case for it turns out to be. It is not a credibility ladder — a primary-document row can still describe a case the cited document itself calls unresolved (the Tehran F-4 file, the Chile 2014 CEFAA review); the label only says the row rests on a document this project checked exists, not that the document settles the question.

On the sightings track, that document is most often official rather than legislative: a Blue Book file, a DIA or CIA report, a UK MoD FOI release, a foreign air force's own investigation or press statement, a gendarmerie or CEFAA/GEIPAN dossier — the kind of record a national investigating body produced about its own case. Several sightings rows cite that document through a secondary compilation (a Wikipedia article summarising the Blue Book file, a wire story summarising an AARO report) rather than the primary source directly. That is still primary-document: the column tracks whether a real document stands behind the claim, not which page the citation happens to link to. What would disqualify a row is a document that cannot be shown to exist at all — at that point the row belongs in assessment instead, and should say so.

On the institutions track, the equivalent documents are a statute, an executive order, an NSC directive, a GAO or congressional record, or a fact sheet a federal agency published about its own history. These establish that an institution or a legal authority existed and did what its own text says. They do not, on their own, establish that the institution ran a UFO programme; where a row's summary draws that connection, the prose says plainly that the connection is a researcher's reading, not the document's own claim.

• primary-document rows, on either track, cite a document this project checked exists.
• assessment rows are a researcher's own interpretation of what a document or event means — for example, reading a 1961 Air Force organisational lineage as continuous custodianship of recovered material, or theorising that Strategic Defense Initiative funds were redirected to a crash-retrieval programme. These are presented as claims, not as findings the row's source establishes on its own.
• single-witness rows rest on one person's account — sworn congressional testimony, a memo recording one person's recollection of what someone else told them, an interview relayed secondhand. A sworn statement and a secondhand memo are different kinds of evidence from each other and from a statute; the basis column does not rank them against one another, and the summary prose says which kind a reader is looking at.

Every primary-document citation added to either track was checked against the source before being entered. Where a document referenced in the source video could not be found or independently verified, the row was written up as assessment or single-witness instead, and the summary says so.

Institutional spine

The institutions track in data/timeline-events.csv lays a second chronology alongside the sightings above: the legal and organisational scaffolding — executive orders, NSC directives, agency foundings, corporate mergers — that later programme-level claims get measured against, plus the testimonial record of people who say they worked inside, or were briefed on, programmes built on that scaffolding.

Until 23 September 2026 every row on this track was American. The gap-fill added above puts the foreign bodies on the same axis — Canada's Project Magnet (1950) and its 1995 closure, the UK's Flying Saucer Working Party (1950–51) and desk closure (2009), France's GEPAN (1977), Uruguay's CRIDOVNI (1979), Chile's CEFAA (1997), Argentina's CEFAE (2011), Peru's DIFAA (2013) — beside the US offices the earlier rows described, so "who was watching, and when" is answerable from one column instead of being split between this file and 02-agencies-and-official-bodies.md.

Eras this timeline makes visible

1. 1883–1946 — pre-history. Photographic and press oddities; no institutions.
2. 1947–1969 — the state investigates. Everything is threat assessment: Project Sign/Grudge/Blue Book, Canada's Magnet and Second Storey, the UK's Flying Saucer Working Party.
3. 1976–1991 — the instrumented decade. Tehran, Petrozavodsk, Colares, Kaikōura, Manises, Rendlesham, Trans-en-Provence, Brazil's Night of the UFOs, Belgium. Radar, interceptors and state laboratories enter the record — and Soviet Setka plus UK/US desks quietly close behind them.
4. 1994–2014 — the long gap. Events still happen (Ariel School, Varginha, Campeche, O'Hare, Chile 2014), but the northern desks close (Canada 1995, UK 2009) while South America opens its own (Chile's CEFAA 1997, Argentina's CEFAE 2011, Peru's DIFAA reopened 2013).
5. 2017–2026 — re-institution. AARO, Japan's caucus, Chile and Uruguay's continuity, France never having stopped, and Pentagon file releases that now cite foreign cases by name.