  As air traffic grows significantly, aircraft accidents increase. Many
aviation accidents could be prevented if the precise aircraft positions and
weather conditions on the aircraft's route were known. Existing studies propose
determining the precise aircraft positions via a VHF channel with an air-to-air
radio relay system that is based on mobile ad-hoc networks. However, due to the
long propagation delay, the existing TDMA MAC schemes underutilize the
networks. The existing TDMA MAC sends data and receives ACK in one time slot,
which requires two guard times in one time slot. Since aeronautical
communications spans a significant distance, the guard time occupies a
significantly large portion of the slot. To solve this problem, we propose a
piggybacking mechanism ACK. Our proposed MAC has one guard time in one time
slot, which enables the transmission of more data. Using this additional data,
we can send weather conditions that pertain to the aircraft's current position.
Our analysis shows that this proposed MAC performs better than the existing
MAC, since it offers better throughput and network utilization. In addition,
our weather condition notification model achieves a much lower transmission
delay than a HF (high frequency) voice communication.
