But wasn't the root cause an improperly shielded lead. In other words it
was supposed to have been shielded but the build or install process failed in
this case. So not necessarily the lack of adequate standards but an improperly
build piece of equipment?
Its been a very long time since I looked at this instance so it could be
faulty memory on my part.
Gary
From: Ken Javor [mailto:[email protected]]
Sent: Thursday, March 27, 2003 3:37 PM
To: [email protected]; [email protected]
Subject: Re: Help wanted with succinct subject description for non-specialists
It is interesting, nonetheless, to note that the disaster occurred in July
1967, and in September of that year, MIL-E-6051C, EMC Requirements, Systems,
was updated to the "D" revision, which for the first time required 20 dB
safety margin demonstrations for EEDs. Coincidence? Perhaps...
Ken Javor
on 3/27/03 1:20 PM, [email protected] at [email protected] wrote:
Sir
I must concur with Mr Woodgate. This particular instance in (very) infamous in
the U.S. Navy & USMC, but mostly for shipboard fire-fighting instruction and
damage control protocol. The flight-deck videos of this are still shown to
students of the fire-fighting school for carrier crew.
The aircraft in question was stationary in the flight deck; it was not in the
landing phase. The failure mode was a faulty connector. One of the major
changes invoked by this disaster was the extensiion/formalization of
enviromental stress testing (shock. vibration, & thermal). EMC was not, IMO,
considered part of the root cause.
R/S,
Brian
-----Original Message-----
From: King, Richard
Sent: Thursday, March 27, 2003 7:18 AM
To: [email protected]
Subject: RE: Help wanted with succinct subject description for
non-special ists
I should reiterate from my original message that the text I posted is the
introduction to an article, not a complete article.
The example was included to engage the reader from the start; demonstrate
that electromagnetic compatibility between systems is a real-world issue;
and show that a lack of EMC can have severe consequences. It highlights the
importance of compatibility between systems in their operating environment,
not the importance of compliance with standards in a laboratory, which I
agree is often a separate matter. Any other examples that illustrate these
points would be gratefully received.
Best regards,
Richard King
Systems Engineer
Thales Communications UK
> -----Original Message-----
> From: John Woodgate [SMTP:[email protected]]
> Sent: Thursday, March 27, 2003 9:54 AM
> To: [email protected]
> Subject: Help wanted with succinct subject description for
> non-special ists
>
> >In 1967 off the coast of Vietnam, a jet landing on the aircraft carrier
> >U.S.S. Forrestal was briefly illuminated by carrier-based radar. This is
> >quite a normal event, however the energy from the radar caused a stray
> >electrical signal to be sent to the jet weapon systems. The result was an
> >uncommanded release of munitions that struck a fully armed and fuelled
> >fighter on deck. The subsequent explosions killed 134 sailors and caused
> >severe damage to the carrier and aircraft.
>
> This is an appallingly bad example, insofar as it was caused by a
> **fault condition**. EMC standards, and the testing itself, do not take
> fault conditions into account. There is a separate subject 'EMC and
> functional safety', which is incredibly complicated. If you just think
> about it for a while, you will see why.
>
> Don't let your audience think that EMI occurs only when source or victim
> is faulty. EMI occurs when both would be working perfectly normally if
> the EMI were not present.
> --
> Regards, John Woodgate, OOO - Own Opinions Only.
--
Ken Javor
EMC Compliance
Huntsville, Alabama
256/650-5261
