降下

1. Origins, structure, and basic meaning

• Structure: 降下 (こうか) is a noun that also forms a する verb for descent from a higher position.
• Basic usage: It describes an aircraft losing altitude or personnel beginning a descent at a signal.
  • 飛行機はゆっくり高度を下げて降下した。 — The airplane descended slowly.
  • 隊員たちは合図に合わせて降下を始めた。 — The team began its descent at the signal.

2. Common pitfalls and similar expressions

• Descent and landing
  • 降下 is the downward movement, while 着陸 is the result of reaching the ground. A descent does not necessarily imply landing.