For a Category A airplane flying the ILS approach, what is the decision height when the altimeter setting is set to 29.87?

In the context of an ILS (Instrument Landing System) approach for a Category A airplane, the decision height (DH) is critical for determining when the pilot must decide whether to continue the approach or execute a missed approach based on visibility and visual references.

For Category A aircraft, which typically includes smaller, slower airplanes, the standard decision height for an ILS approach can vary based on the specific approach chart. The DH is set based on the minimums indicated for the ILS approach, which are influenced by factors such as weather conditions and the specific category of the approach being flown.

In this case, with an altimeter setting of 29.87 inches of mercury, the appropriate decision height for a Category A aircraft is 280 feet AGL. This height is derived from the standard minimums for ILS approaches where higher altimeter settings can lead to a higher decision height. Therefore, with the altimeter set correctly and the aircraft operating under the defined parameters for ILS approaches, 280 feet AGL represents the height at which visual reference must be established to continue the approach safely.