When can landing gear be successfully extended normally?

The correct answer is based on the operational parameters of an aircraft's landing gear system. Landing gear can only be successfully extended normally when the aircraft is below the maximum extended airspeed limit. This is crucial for ensuring that the landing gear deploys correctly and functions as intended. Extending the gear at speeds above this limit can potentially lead to mechanical failures or malfunctions, as the aerodynamic forces may impact the gear's deployment and locking mechanisms.

By adhering to the maximum extended airspeed limit, pilots can ensure that the landing gear is not subjected to excessive forces, which could cause it to malfunction or fail to deploy properly. This guideline is part of standard operating procedures that enhance both safety and efficiency during flight operations.