Definition
Autopilot or autothrottle modes that automatically maintain a selected airspeed or Mach number by adjusting pitch attitude, thrust, or both. In a typical configuration, the autopilot holds the target speed by varying pitch (trading altitude for speed) while the autothrottle holds it by varying engine thrust.
Plain English
Settings on the autopilot that lock the aircraft onto a chosen speed and keep it there automatically, so the pilot doesn't have to constantly adjust pitch or thrust to maintain it.
Context Anchor
Seen in instrument flying and abnormal-weather guidance, especially when discussing what automation to avoid during severe turbulence or a thunderstorm encounter.
Why Pilots Care
Prevents dangerous speed changes that could cause loss of control or structural stress in thunderstorm turbulence.
Grounding Statement
In a thunderstorm encounter, the goal is usually to keep the aircraft under control, not to let automation chase every speed change.
Intuition Check
“Hold” does not mean the aircraft speed will stay perfectly fixed. Here, it means the automation will keep trying to return the aircraft to the selected speed.
Example Sentence 1
Before entering the area of suspected convective activity, the crew disengaged the speed hold modes and set a known pitch attitude and power setting for turbulence penetration.
Example Sentence 2
Switching to speed hold prevented the airspeed from dropping too low during heavy turbulence.