Mailing List lml@lancaironline.net Message #21065
From: Brent Regan <brent@regandesigns.com>
Sender: Marvin Kaye <marv@lancaironline.net>
Subject: Re: Of Men and EFIS
Date: Sat, 18 Oct 2003 15:26:06 -0400
To: <lml@lancaironline.net>
Jerry:

Thank you for your reinforcement of the importance of human factor considerations in panel layout. I would like to clarify a couple of points in the interest of fairness, accuracy and safety.

Regarding Kirk, I am confused as to how his words of support towards BMA, back when he was selling BMA products, were valid but now, when he represents CFS, his words are not valid. Either Kirk is capable of forming an opinion independent of potential financial rewards or he is not. You cannot selectively and simultaneously promote and disparage his opinions. In my experience people tend to become wiser in the fulness of time.

You write: <<
However I really do not agree with Brent that the reason that laptops have to be turned off during airliner take off and landing is
interference with the navigation and communication equipment.
>>

Agree or not, it is the FAA stated reason (FAR Part 121.306) and includes laptops, cell phones, PDAs, Blueberries, two way pagers,  etc. Only Voice recorders, Electric shavers, Heart pacemakers , Hearing aids and "Any other portable electronic device that the part 119 certificate holder has determined will not cause interference with the navigation or communication system of the aircraft on which it is to be used." are allowed to be active.

You write:<<
Electro Magnetic Compatibility (EMC). <snip> It won't appear just because
you go IMC. As with all these things, first try it in controlled conditions.
>>

Electro Magnetic Interference (EMI) testing covers emissions and susceptibility to radio frequencies and HIRF (High Intensity Radiated Fields) AKA Lightning. While some radiated emission problems can be detected in a ramp test, many cannot. Specifically those that degrade but do not block signals. Your EFIS may block half of the GPS signals reaching your receiver but you can still get a lock on the remaining 4 signals, for now. Maybe not later.

It is not practical to test the systems susceptibility to EMI and HIRF on the ramp and you may ONLY see these conditions in IMC. P-static and Lightning HIRF come to mind. How will you test for those but in a lab?

You write:<<
Chelton system is different from the certified version. It is not just that
they do not include the paper certificate with the box, the unit is
physically different and has not been certified. So it appears to me to be
neither better nor worse than the BMA system in this one respect.
>>

Appearances can be deceiving. Certification efforts began on the experimental EFIS and  most of the physical testing (Temperature, vibration, EMI etc.) was already done when Chelton won the Capstone contract. The box had to be redesigned (per the contract) to make it narrower so it would fit in a radio stack and all the tests had to be repeated. Not wanting to sound like all the others in the field claiming robustness without offering proof, CFS made a video of some of the more dramatic tests on the experimental system. Admittedly there was some Hollywood involved (DO160D does not have a "Fry an egg on the case" test) but only by way of illustration. No fakery was involved. Copies of this video are available from CFS.

You write:<<
I do not particularly like messages promoting systems in which the correspondents have a personal or financial interest.
>>

Does that include yours? You spent a large sum of money on a particular system, you seem to want to justify that expense and you need that company to survive so it can support your system, therefore you, Jerry, have a personal interest.

This list is, in part, a vehicle for enhancing safety and improving understanding of the complex issues surrounding aviation. It is also a place where the "peer review" elements will not tolerate lies, prevarication, misstatements and misrepresentations. It is a place where falsehoods get savaged by facts and the truth. Those savaged tend to characterize this as "flaming" or "personal attacks" because if they can't make their point with logic and facts they may be able to make it with emotion.

If anyone can show that I have made any statements that are untrue then I will post an immediate correction and apology.

Now I am done. No fork needed.

Regards
Brent Regan





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