Subject: presentation-prep as safety hazard

From: "RL 'Bob' Morgan" <[email-masked]>
Date: Mon, 19 Mar 2001 19:11:02 -0800 (PST)

On the plane last night, flying in to Minneapolis:

"We're now starting our descent, please return your tray tables and seat
backs to their upright and locked position, and turn off any electronic
equipment."

2 minutes later:

"People!  We really need you to turn those laptops off NOW ..."

 - RL "Bob"

---

From: "Linn, John" <[email-masked]>
Date: Tue, 20 Mar 2001 09:08:48 -0500

I feared it was some sort of omen on Sunday evening when I arrived at the
Minneapolis airport and found one of the departure gate monitors
superimposed with a Windows error pop-up saying "Windows has detected an IP
addressing conflict".  It didn't seem clear who'd be in a position to click
"OK"...

--jl

-----Original Message-----
From: Dave Crocker [mailto:[email-masked]]
Sent: Monday, March 19, 2001 8:28 PM
To: RL 'Bob' Morgan
Cc: [email-masked]
Subject: Re: presentation-prep as safety hazard

>"People!  We really need you to turn those laptops off NOW ..."

On the way here, the flight attendant insisted that I turn off my Palm
Pilot.

Do they make people turn off hearing aids?

d/

----------
Dave Crocker   <mailto:[email-masked]>
Brandenburg InternetWorking   <http://www.brandenburg.com>
tel: +1.408.246.8253;   fax: +1.408.273.6464

---

From: "Maddux, Michel" <[email-masked]>
Date: Tue, 20 Mar 2001 12:02:08 -0600

-----Original Message-----
From: John Stracke [mailto:[email-masked]]

>>(The difference, of course, is that there's no Hearing Aid VII, with a
wireless
>>connection to let you listen to Web pages or something...yet.  The flight
>.attendants can't keep up with the tech; and better for them to err on the
side
>>of caution.  The remaining question, of course, is how come the airplane
>>manufacturers can't build a plane to resist this interference.  

They can; today's fleet is pretty old.  A lot of the Boeing 737's were put
into service
in the '70's.  The 727's are even older. 

The newer aircraft would not likely have the same problem, however, one size
fits
all when it comes to policy. /m.

---

From: Harald Alvestrand <[email-masked]>
Date: Tue, 20 Mar 2001 23:23:35 +0100

>"People!  We really need you to turn those laptops off NOW ..."

note that having a PC with a 500 MHz clock means that there is an 
oscillator in there running at some hundreds of megahertz, attached to a 
nest of wires of uncertain shape.

this particular setup WILL transmit energy in the radio bands below 500 MHz.

--
Harald Tveit Alvestrand, [email-masked]
+47 41 44 29 94
Personal email: [email-masked]

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From: "Gallant, Andy" <[email-masked]>
Date: Wed, 21 Mar 2001 14:35:44 -0600

Below is the beginning of an FAA Advisory Circular that suggests
more places to look.

-Andy Gallant

From: http://www.faa.gov/avr/afs/acs/ac91211a.pdf

	Subject: USE OF PORTABLE ELECTRONIC 
	DEVICES ABOARD AIRCRAFT 
	Date: 10/02/00 
	AC No: 91.21-1A
	Initiated by: AFS-330 
	Change:
	_______________________________________
	1. PURPOSE. This advisory circular (AC) provides aircraft
	operators with information and guidance for assistance in
	compliance to Title 14 of the Code of Federal Regulations 
	(14 CFR) part 91, section 91.21. Section 91.21 was 
	established because of the potential for portable 
	electronic devices (PED) to interfere with aircraft 
	communications and navigation equipment. It prohibits the 
	operation of PED's aboard U.S.-registered civil aircraft, 
	operated by the holder of an air carrier operating 
	certificate, an operating certificate, or any other 
	aircraft while operating under instrument flight rules 
	(IFR). This rule permits use of specified PED's and other 
	devices that the operator of the aircraft has determined 
	will not interfere with the safe operation of the 
	aircraft in which it is operated. The recommendations 
	contained herein are one means, but not the only means, 
	of complying with section 91.21 requirements, pertaining 
	to the operation of PED's.

	...

------

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From: "Maddux, Michel" <[email-masked]>
Date: Wed, 21 Mar 2001 16:00:04 -0600

>> Couched in friendlierterms, the discussion might have been:

>>A: I have never seen actual evidence that a problem exists.
>>B: I have.
>>A: Oh, really?  Where?
>>B: I don't know.  But I've definitely seen it - perhaps if you looked, you
would too.

Of course you are correct, and I apologize for the testy reply earlier.
A very interesting thread anyway; the NTSB web site has a very nice search
engine, and thousands of entries (sigh; one for each crash since 1983,
domestic US anyway).  As a 100K flier for many years, I personally relish
the opportunity to turn off the umbilical cord to the office and quietly
read a journal.  I would much rather be out of touch than be another report
in the NTSB database.

>>At any rate, http://www.srg.caa.co.uk/news/Gsm_intf.PDF seems to indicate
>>that there are no recorded incidents of people eating each other to stay
>>alive on the side of a snow covered mountain, and later discovering that
>>it was all on account of a cell-phone.  

[... but, but, but, sputtering noises... ;^)]

From a delightful paper entitled "Internet Telephony" by
Schulzrinne/Rosenberg: 

A while back, German scientists dug 50 meters down in the underground and
discovered small
pieces of copper. After studying these pieces for a long time, Germany
announced that the ancient
Germans 25,000 years ago had a nation-wide telephone network. Naturally, the
Russian
government was not that easily impressed. They ordered their own scientists
to dig even deeper.
100 meters down they found small pieces of glass and they soon announced
that the ancient
Russians 35,000 years ago already had a nation-wide fiber net. Ethiopian
scientists were
outraged. They dug 200 meters down in the underground, but found absolutely
nothing. They
happily concluded that the ancient ethiopians 55,000 years ago had cellular
telephones.
I have always wished that my computer would be as easy to use as my
telephone. My wish has
come true. I no longer know how to use my telephone.
Bjarne Stroustrup (author of the C++ programming language)

so, my conclusion?  Even 50,000 years ago, the problems of society,
including recent incidents of airline failure, cannibalism, and heartburn,
can be directly traced to the invention of the cell phone. ;^) 

thanks. /m.

---

From: Harald Alvestrand <[email-masked]>
Date: Wed, 21 Mar 2001 22:45:47 +0100

At 13:05 21/03/2001 -0500, Rosen, Brian wrote:
>Well, but
>         Most PC designs use phase lock techniques which keep external
>                 signals way below the CPU operating frequency

The usual multiplier is in the single-digit range. That's why I said "some 
hundreds of megahertz". And don't forget the harmonics....a 100-MHz square 
wave (or reasonable facsimile thereof) has a major harmonic component at 
300 MHz.

>         There are legal limits for radiation; most laptops and all
>      PDA devices are "Class B" which is a pretty low level.
>The real issue I suspect is that there is no practical way to test
>what the effect of a whole planefull of "at-the-limit" devices do
>to the plane's systems. It is very reasonable to design the avionics
>to be hardened against this sort of thing, but the older planes wouldn't
>have such avionics.

control systems on older planes (pre-1970) are actually more robust, 
because they use a lot more analog and hydraulics rather than avionics.
nav systems are another matter, of course.

>I expect we will see some lessening of the rules as the experience
>and turnover of the airframes proceeds.  We already have the
>"mobile use okay until pushback" which is a real change.

hasn't arrived in Europe yet, unfortunately.

---

From: "sebastien.dorey" <[email-masked]>
Date: Thu, 22 Mar 2001 12:12:51 +0100

Marshall T Rose <[email-masked]> writes:

> a rationale reason for asking folks to turn the things off is because
> the airlines don't want people to be distracted during take-off and
> landing, when most things tend to go wrong. if they'd just come out
and
> say this, most people would probably accept it.

I thought that we had to turn the things off just because of the interaction

of the equipment in the airplane during take off ands landing.

--
What's important is not simplicity or complexity, but how you bridge the two.
                                                    Larry Wall, Aug. 25, 1998
url :http://www.epita.fr/~dorey_s