What happened
A Southwest Airlines Company Boeing 737, operating Flight Number 558, was en route from Denver, Colorado, to Albuquerque, New Mexico. The aircraft was cruising at flight level 350 when it encountered severe clear air turbulence. This unexpected weather phenomenon caused the aircraft to drop suddenly. As a result of the sudden movement, two flight attendants were injured. After the aircraft was brought back to level flight, the remainder of the flight proceeded without further incident.
The investigation
The provided source text does not contain specific details regarding a mechanical examination or technical investigation findings beyond the immediate weather encounter and resulting injuries.
Findings
The primary finding was the encounter with severe clear air turbulence at high altitude. This atmospheric condition led to the sudden vertical displacement of the aircraft, which directly caused physical injury to crew members who were not secured in their seats during the event.