TCH on approach plate - utility

[shon7]

Whats the significange/utitlity of Threshold Crossing Height (TCH) on an approach plate? How is this information useful

 

[propilot]

It's useful when you fly an airplane where the gear hangs significantly lower than your seat...

We require a minimum 47' TCH so we don't take out any lights...

 

[PURPLEHAZE21]

Example: When a DC-10 crosses the runway threshold, its main gear wheels are only 26 feet from the runway due to its size and angle. Getting a dot off glideslope or flying a Cat II, or III becomes more detremental ...quick.

 

[avbug]

We used TCH to determine the minimum autopilot disconnect height. For TCH below 47', our minimum autopilot altitude on an approach was 150', but if the approach was conducted to a runway with a TCH above 47', we could go to 100' on the autopilot.

Especially in larger airplanes, where a lot of airplane is behind and below you on the approach, the TCH is important to know.