A system for time synchronization over switch-based avionics networks, comprising: at least one source clock installable aboard an aircraft, the source clock associated with a source time and configured to: receive at least one timing signal from a navigational satellite; update the source time based on the timing signal; generate at least one timing message based on the updated source time, the timing message associated with a message format compatible with at least one redundant network (102, 202); and receive at least one modified delay request; wherein the source clock comprises: at least one backup clock coupled to the source clock and associated with a backup time, the backup clock configured to: update the backup time based on the updated source time; and store the updated backup time to a memory; and at least one auxiliary power source coupled to the backup clock, the auxiliary power source configured to supply operating power to the backup clock; at least one network switch in communication with the source clock and with the at least one redundant network, the network switch configured to: receive the timing message from the source clock; receive a delay request from at least one end system via the redundant network; modify at least one of the received timing message and the received delay request to account for a delay associated with the network switch; relay the modified timing message to the at least one end system via the redundant network; and relay the modified delay request to the source clock; and each of the at least one end system including at least one destination clock in communication with the network switch and associated with a system time, the destination clock configured to: receive the modified timing message from the network switch; generate the delay request in response to the modified timing message; and synchronize the system time according to the source time based on one or more of the modified timing message and the delay request. at least one source clock installable aboard an aircraft, the source clock associated with a source time and configured to: receive at least one timing signal from a navigational satellite; update the source time based on the timing signal; generate at least one timing message based on the updated source time, the timing message associated with a message format compatible with at least one redundant network (102, 202); and receive at least one modified delay request; receive at least one timing signal from a navigational satellite; update the source time based on the timing signal; generate at least one timing message based on the updated source time, the timing message associated with a message format compatible with at least one redundant network (102, 202); and receive at least one modified delay request; wherein the source clock comprises: at least one backup clock coupled to the source clock and associated with a backup time, the backup clock configured to: update the backup time based on the updated source time; and store the updated backup time to a memory; and at least one auxiliary power source coupled to the backup clock, the auxiliary power source configured to supply operating power to the backup clock; at least one backup clock coupled to the source clock and associated with a backup time, the backup clock configured to: update the backup time based on the updated source time; and store the updated backup time to a memory; and update the backup time based on the updated source time; and store the updated backup time to a memory; and at least one auxiliary power source coupled to the backup clock, the auxiliary power source configured to supply operating power to the backup clock; at least one network switch in communication with the source clock and with the at least one redundant network, the network switch configured to: receive the timing message from the source clock; receive a delay request from at least one end system via the redundant network; modify at least one of the received timing message and the received delay request to account for a delay associated with the network switch; relay the modified timing message to the at least one end system via the redundant network; and relay the modified delay request to the source clock; and receive the timing message from the source clock; receive a delay request from at least one end system via the redundant network; modify at least one of the received timing message and the received delay request to account for a delay associated with the network switch; relay the modified timing message to the at least one end system via the redundant network; and relay the modified delay request to the source clock; and each of the at least one end system including at least one destination clock in communication with the network switch and associated with a system time, the destination clock configured to: receive the modified timing message from the network switch; generate the delay request in response to the modified timing message; and synchronize the system time according to the source time based on one or more of the modified timing message and the delay request. receive the modified timing message from the network switch; generate the delay request in response to the modified timing message; and synchronize the system time according to the source time based on one or more of the modified timing message and the delay request.