minor point of clarification. The DO160 document referred to is published by RTCA and not the FAA. The latest version is DO160E released about a year ago. It is an environmental test procedures document that covers much more than just lightning. Section 20 covers indirect effects of lightning (effects of lightning currents induced into aircraft wiring) section 22 covers direct effects of lightning (damage to aircraft structure or anything like antennas or probes that protrude from the skin.
The FAA does publish an advisory circular AC 20-136 "Protection of Aircraft Electrical/Electronic Systems against the Indirect Effects of Lightning" It was published in 1990 and is somewhat out of date. An interesting twist, one of the simulated lightning tests is called a multi-burst test. The test equipment generators commonly used for this test look very similar to early spark gap transmitters. John Lock KF0M Wichita KS kf0m at arrl dot net > -----Original Message----- > From: Repeater-Builder@yahoogroups.com > [mailto:[EMAIL PROTECTED] Behalf Of Dick > Sent: Friday, December 30, 2005 6:43 PM > To: Repeater-Builder@yahoogroups.com > Subject: Re: [Repeater-Builder] polyphaser Help > > > Paul, I wouldn't worry unless you plan to operate your van on a > mountain top in one of those impressive upstate NY lightning storms. > > As for protecting aircraft, first you spec out all avionics to survive a > brief > 500 V blast on any wiring that goes outside the fuselage > (typically antenna > cables). Then you make sure that all metal joints and faying > surfaces have > a DC resistance not more than .0025 ohms. Via Ohm's Law, you'll see > that 250 K amps and .0025 ohms comes out to 500 V. Also, all avionics > boxes will have dedicated bonding straps to the airframe. Other > considerations > get right down into the design of the avionics boxes. All antennas are DC > grounded to the fuselage. > > Last, but certainly not least, you talk with the folks who write the > aircraft > operating manuals and put in an instruction that tells the crew > not to fly > into > thunderstorms and to avoid flight in areas likely to produce lightning. > Then > you hope and pray that, during their flight training, they were > taught how > to > spot weather conditions likely to spawn lightning. I was. My instructors > drilled that weather info into my feeble brain until I could recite in my > sleep > and spot a potential lightning strike area and avoid it. > > You can get a pretty good idea of this stuff in an FAA publication. > It has the exciting title DO-160-? The ? is for whatever the > latest version > is. > > Happy New Year, > > Dick > > ----- Original Message ----- > From: "Paul Yonge" <[EMAIL PROTECTED]> > To: <Repeater-Builder@yahoogroups.com> > Sent: 30 December, 2005 16:23 > Subject: Re: [Repeater-Builder] polyphaser Help > > > > On Dec 30, 2005, at 7:10 PM, Dick wrote: > > > After a lot of years at Lockheed designing lightning protection for > > military aircraft, I've developed a very healthy respect for the > > stuff. > > Out of curiosity, how does one design lightning protection for aircraft? > > I've avoided worrying about lightning protection for the mobile > repeater van I'm putting together. Should I be worrying? > > > Paul Yonge > WQDY219 > MIDLAKES REPEATER > Syracuse, New York > > > > > > > Yahoo! Groups Links > > > > > > Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
