What happened
On the morning of the accident, a privately-registered Mooney M-20F, registration C-GGIK, was performing local familiarization flights near St. Andrews, Manitoba, as part of a Girl Guide Jamboree. After completing two previous flights, the pilot departed from runway 1ob at 11:21 CDT carrying three passengers. The aircraft climbed to approximately 340 feet and turned east. During this maneuver, the aircraft leveled off, rolled sharply to the left, and entered a spiral dive. The aircraft struck a residential area approximately 75 feet from a house, resulting in four fatalities.
The investigation
The investigation focused on the aircraft's mechanical condition and the sequence of the aerodynamic stall. Investigators examined the engine, finding corrosion in the fuel pump and contamination in the fuel-control filter. While the fuel pressure remained adequate at impact, the engine tachometer indicated a significant drop in RPM, suggesting a power loss. The investigation also reviewed the aircraft's maintenance history, noting that Airworthiness Directive 85-24-03 had not been performed, which left certain rib drain holes sealed with sealant.
Analysis of the fuel system revealed water contamination. Because the drain holes were blocked, water trapped in the wing tanks could not be purged using standard procedures. The investigation also reviewed the pilot's records, noting a valid private license and no evidence of impairment, though traces of acetaminophen were found in the body.
Findings
- The engine lost power, likely due to water contamination in the fuel.
- The pilot failed to maintain sufficient airspeed following the power loss, leading the aircraft to stall and enter a spin.
- The aircraft's stall warning horn was functional and was heard on the tower audio tape immediately before the stall.
- A tailwind component during the turn may have created a speed illusion, masking the rapid reduction in airspeed.
- The failure to comply with AD 85-24-03 prevented the removal of water trapped behind the wing ribs.
- Recovery from the spin was unlikely given the low altitude of 340 feet.