Descents

10 clues
Downturns
Flight finishes
Assaults; forays
Submarine actions
They lead to landings
Thrills for sky divers
Parts of mountaineering trips
Thrill-givers on roller coasters
Conclusions of mountaineering trips
Starts of many spelunking explorations
Similar answers:
Abasements
Abatements
Absents
Abutments
Accents
Accentshappen
Accentswillhappen
Accidents
Accidentsarewaiting
Accidentshappen
Accomplishments
Accoutrements
Acquiescents
Adddetergents
Addonestwocents
Adepartmentstoreandhe
Adeschool
Adherents
Adjustments
Adolescents