Unstable approach — THU870

THU870 (Thunder Airlines) was operating from CYTZ to CYSB on 2026-09-04. SkyMeter detected a low approach-stability score at Sudbury Airport (CYSB) on runway 04 at 17:43 UTC. Trace data at the event: 2262 ft AGL, 175 kt GS. Approach stability score: 20/100. Scores below 50 occur on under 10% of approaches at this runway and indicate the v2 scorer flagged the approach as highly anomalous (three or more gates exceeded the runway's P90 envelope simultaneously). METAR at the time reported 8 kt wind, 4 kt crosswind component, 32,187 m visibility. The approach-stability score rates the final approach against stabilized-approach gates (glideslope, lateral deviation, descent rate, and IAS) at defined altitudes. A low score means one or more of those were outside the normal envelope for how the approach was flown. The score is graded by guidance type, so instrument approaches (ILS or an aligned straight-in) are held to the full gate set, while visual and pattern arrivals are surfaced only when the score is clearly low. The score is advisory and observational, a deviation measure, not an assertion of an accident. Detection algorithm and known limitations: see SkyMeter methodology.

Automated analysis. Events shown on this page (such as go-around, unstable approach, or runway events) are heuristic classifications produced by algorithms from publicly broadcast ADS-B data. They are intended to surface flights of interest for further review — they are not findings of fact, and they do not determine pilot fault, regulatory compliance, or the cause of any occurrence. Coverage gaps and sensor noise can affect accuracy. Only the relevant civil aviation authority or accident investigation body can make official determinations. How we detect events · Dispute or correct this data