Local Area Networks (LANs) in Aircraft - FTP Directory Listing - FAA

Three respondents wrote in helpful observations that provided additional insight into their
responses to question 24. The following are direct quotations of their hand-written comments:
• “Any breech of security can result in danger to the thing the security was
intended to protect. If it was not possible to cause harm to the aircraft or
passengers by breeching the security, then why is there any security there
• to breech? Or is the question trying to assess probabilities? With respect
to LANs, the safety risk is entirely dependent on what is connected to the
LAN. If a safety critical device is connected to the LAN and there is a
possibility of bad data getting to it, then there is, by definition, a safety
risk. The severity depends entirely on what devices are connected to the
LAN and what they use the LAN for. As written, it may not be possible to
provide a meaningful answer to the question.”
• “Please note: responses to 24 assume airborne LAN is a separate system
from flight avionics. If this is an invalid assumption, all answers are
‘Yes.’”
• “Note: the answer to most of these questions is heavily dependent on the
architecture of the LAN. If there are bridges to avionics software then
there is a security risk. If we are only talking about internet use of a LAN
that is not in any way tied to the flight essential or critical software then
the security risk may be mute.”
B-7/B-8