For aircraft 5 and 7, which OMNI indications would be received?

The correct answer indicates that the OMNI indications received for aircraft 5 and 7 would be W and Z. In the context of navigational aids, the OMNI system transmits signals that provide directional information to aircraft relative to navigational beacons.

W and Z are typically distinct OMNI signals that might correspond to specific navigational routes or airways relevant to those particular aircraft's flight paths or positions at the time of measurement. By identifying these signals, pilots can maintain proper course or make necessary adjustments based on the information provided by the OMNI system.

Receiving accurate OMNI indications is critical for navigational safety, as it ensures that aircraft are aware of their position concerning fixed reference points. Understanding the specific indications (W and Z in this case) enables pilots to utilize their instruments effectively, hence making it clear why this answer is correct.