Navigation aids are radios. They are designed to have these sensitivities. The balance of the suite of avionics have their RE controlled to protect these radios. It all works. If an on-board rfi source such as a portable CD player or laptop interferes with the operation, this is not a catastrophic issue because the pilot, seeing a sudden change in position relative to the runway, and not having felt any accompanying acceleration would immediately deduce his instrumentation was malfunctioning and take appropriate steps. It is only when the navigational aids are tied to the auto-pilot and the auto-pilot doesn't have the intelligence to discern an impossible reading from the navigation aid that the potential for immediate catastrophe looms. This was the case with the DC-10 that is the origin of the rule to turn off personal electronics on take-off and landing. In the case of the DC-10, the pilot seized control from the auto-pilot and redirected the aircraft towards its former heading. Since this was on final approach, it was a fairly narrow escape.
---------- >From: John Woodgate <j...@jmwa.demon.co.uk> >To: emc-p...@majordomo.ieee.org >Subject: Re: EMC-related safety issues >Date: Tue, Jan 1, 2002, 1:54 PM > > > I read in !emc-pstc that Ken Javor <ken.ja...@emccompliance.com> wrote > (in <20020101193617.STGC6581.femail3.sdc1.sfba.home.com@[65.11.150.27]>) > about 'EMC-related safety issues', on Tue, 1 Jan 2002: >> The >>standard navigational aids: ILS, TACAN and VOR all have simple modulation >>schemes. ILS receivers have sensitivities on the order of -90 dBm, TACAN is >>-80 dBm, glide slope -60 dBm and marker beacon -50 dBm. > > Yes, that's what I had in mind. Surprisingly vulnerable. > -- > Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk > After swimming across the Hellespont, I felt like a Hero. > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Michael Garretson: pstc_ad...@garretson.org > Dave Heald davehe...@mediaone.net > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > Jim Bacher: j.bac...@ieee.org > > All emc-pstc postings are archived and searchable on the web at: > No longer online until our new server is brought online and the old > messages are imported into the new server. > ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
