Final answer:
To engage the ILS DECL mode, the indicated airspeed must be above 150 kts.
Step-by-step explanation:
The subject of this question is Physics and it is at a High School level.
To engage the ILS DECL mode, the indicated airspeed must be above __150__ kts.
ILS stands for Instrument Landing System, and DECL mode is one of the modes of ILS. It is used to align an aircraft with the runway during approach and landing. The indicated airspeed requirement may vary based on the specific aircraft and ILS equipment being used, but as a general guideline, it is commonly around 150 knots or higher.