Anyone have an idea what these large amounts of User Data are in the logs if they are not ACARS? (T-Channel RX)
Also would one emergency land a T7 in the dark at Penang without comms from the South West or from the North East?
4.1.1.2.1 P channel. Packet mode time division multiplex(TDM) channel transmitted continuously from the aeronautical ground earth station (GES) in the to-aircraft direction to carry signalling and user data. A P channel being used for system management functions is designated Psmc, while a P channel being used for other functions is designated by Pd. The functional designations Psmc and Pd do not necessarily apply to separate physical channels.
4.1.1.2.2 R channel. Random access (slotted Aloha) channel, used in the from-aircraft direction to carry signalling and user data. An R channel being used for system manage-ment functions is designated Rsmc, while an R channel being used for other functions is designated Rd. The functional designations Rsmc and Rd do not necessarily apply to separate physical channels.
4.1.1.2.3 T channel. Reservation time division multiple access (TDMA) channel, used in the from-aircraft direction only. The receiving GES reserves time slots for transmissions requested by aircraft earth stations (AESs) according to message length. The sending AES transmits the message in the reserved time slots according to priority.
4.1.1.2.4 C channel. Circuit-mode single channel per carrier (SCPC) channel, used in both to-aircraft and from-aircraft directions. This channel is time division multiplexed to provide a primary channel for voice or data traffic and a sub-band channel for signalling, supervision and data messages. The use of the channel is controlled by assignment and release signalling at the start and end of each transaction.
The 4 channel designations in the SATCOM log, FYI.