Definition
The minimum rate of altitude gain, expressed in feet per nautical mile, that a helicopter must be able to achieve during a missed approach to safely clear obstacles along the published missed approach path. The required gradient is set by the instrument approach procedure designer; the helicopter's ability to meet it is determined by performance data in the Rotorcraft Flight Manual for the current weight, altitude, and temperature.
Plain English
If you have to break off an approach and climb away, the procedure tells you how steeply you need to climb. This is the rule about how much altitude you must gain for every mile you fly forward, and you have to confirm your helicopter can actually do it on that day.
Context Anchor
Seen when reviewing helicopter instrument approach procedures and checking the Helicopter Flight Manual to confirm the helicopter can meet the required climb performance.
Derivation
“Gradient” comes from an older word meaning “step” or “degree.” In flying, it helps to think of a climb gradient as the upward slope of the aircraft’s path, not just how fast the aircraft is climbing straight up.
Why Pilots Care
Helicopters often operate at lower climb performance than airplanes; failing to meet the published gradient can result in terrain or obstacle contact during a missed approach in IMC.
Analogy
A road can have a gentle or steep grade. A climb gradient is similar: it describes how steep the helicopter’s climb path must be as it moves forward.
Grounding Statement
Picture going around from an instrument approach: the helicopter must climb enough, soon enough, to clear terrain or obstacles along the published escape path.
Intuition Check
Do not assume this means only vertical climb rate. A climb gradient is height gained compared with distance traveled forward, so the required climb rate changes with speed across the ground.
Example Sentence 1
Before accepting the approach, the pilot checked the flight manual to confirm the helicopter could meet the 400 feet per nautical mile missed approach climb gradient at the current weight and temperature.
Example Sentence 2
Because the helicopter could not meet the published missed approach climb gradient in the current weight and temperature, the pilot chose an alternate airport with a lower requirement.