FAA IFT-12 Mishap Investigation Rationale Detailed — Why Raptor 3 Boostback Failure Triggered Mandatory Starship Grounding

On May 29, 2026, Tesla Oracle published a detailed explainer on why the FAA triggered a mandatory mishap investigation following Starship Flight 12 (IFT-12) on May 22. The investigation focuses on the IFT-12 Booster 19 anomaly in which multiple Raptor 3 engines in the outer ring failed to ignite during the boostback burn sequence, causing the Super Heavy booster to spin out of control and impact the ocean at transonic speed (~1,450 km/h) rather than executing the planned boostback and re-entry burn. Under FAA regulations (14 CFR Part 401 and the Mishap Investigation requirements in SpaceX's launch license), any deviation from the approved flight safety plan constituting an anomaly during the powered flight phase triggers a mandatory mishap investigation. SpaceX previously identified the root cause on May 24 — a Raptor 3 outer ring fuel pre-conditioning failure during rapid boostback ignition sequencing — but the formal FAA process requires SpaceX to submit a full root cause analysis and corrective action report. The FAA must review and accept the corrective actions before issuing a modified launch license for IFT-13. Aviation Week separately confirmed the investigation is expected to resolve by late June 2026 at the earliest, with IFT-13 (Booster 20 + Ship 40) now targeting July–August 2026. The grounding is the sixth in Starship's flight test history and has been flagged as a material risk factor in SpaceX's S-1 filing for its planned Nasdaq (SPCX) debut on June 12, 2026.