Research Log - 2026-05-02 TSO ETSO Source Hardening
Objective
Create the regulator/article-approval source layer that the DO-229 cycle identified as the next institutional gap: FAA TSO-C145e/C146e and EASA ETSO-C145e/C146e.
Source posture before this cycle
- Source - RTCA DO-229 correctly identified FAA/EASA TSO/ETSO material as approval-context evidence.
- The KB did not yet have dedicated source notes for FAA TSO-C145e/C146e or EASA ETSO-C145e/C146e.
- Several downstream pages still had to describe approval boundaries generically rather than linking to explicit regulator-source anchors.
Public sources reviewed
| Source family | Public evidence used | Editorial use |
|---|---|---|
| FAA TSO overview | FAA public TSO page defining TSO as a minimum performance standard and separating TSOA from installation approval | Strong approval-boundary rule |
| FAA DRS TSO-C145e/C146e records | Public DRS/search signals locating the TSO records and DO-229E relationship snippets | Source identity and future extraction routing; not full TSO extraction |
| FAA AC 20-138B | Public airworthiness guidance for installed positioning/navigation equipment | Context for installation/airworthiness separation, used cautiously |
| EASA ETSO-C145e PDF | Public EASA PDF text-extracted in this cycle | Dedicated source note with extracted scope, DO-229E, Class Beta, and integration-boundary signals |
| EASA ETSO-C146e A1 PDF | Public EASA PDF text-extracted in this cycle | Dedicated source note with extracted scope, DO-229E, Class Gamma/Delta, CCA option, and aircraft-level-boundary signals |
| EASA ETSO list / NPA context | Public EASA list and rulemaking context | Secondary context only; not used to create operational claims |
Files created
Files patched
- Source - RTCA DO-229
- SBAS Standards Source Matrix
- SBAS Source Backlog
- SBAS-Standards-Regulation
- SBAS-vs-Other-Standards
- SBAS-Research-MOC
- SBAS in Civil Aviation MOC
Documentation-quality decisions
- FAA and EASA material were treated as regulator/article-approval source layers, not as operational approval layers.
- The FAA note is deliberately conservative because the specific TSO PDFs were located through public DRS signals but not fully extractable in this cycle.
- The EASA note is stronger because the public PDFs were retrieved and text-extracted, but it still avoids replacing official source review, aircraft-level certification, installation manuals, and operational approvals.
- No LPV minima, alert limits, protection-level equations, receiver algorithms, or aircraft eligibility claims were introduced.
- The standards matrix now separates MOPS, FAA TSO, EASA ETSO, installation approval, operational approval, and procedure/service availability.
Recommended next cycle
Proceed to procedure-design/PBN source notes for LPV, LP, LNAV/VNAV, RNAV, and RNP claim boundaries. The equipment and approval-source backbone is now stronger, but operational procedure claims still require the procedure-design/AIP/operator/regulator layer before numerical or eligibility statements can be expanded.