Major misunderstanding here: The fuel pump incident and the flight
director/laser issues are separate. I'm a private pilot and have a good
understanding of many of the flight systems and it makes absolutely no sense
to me!
On the Johannesburg to Cape Town leg of a recent flight to Miami, the pilot
announced that they were having problems with the flight director and would
everyone please turn off ALL electronics, especially computers that
contained CD ROMS. He made a second plea 10 minutes later.
When the pilot informed me about the fuel pump issue he was very grave. I
asked him what Boeing said about the incident and he stated that Boeing
simply said all laser devices must be turned off. I can also state that SAA
is very serious about the laser issue. At the same time I asked the pilot if
he had any problems with me using a GPS and he said "Absolutely no problem
at all". Later when I was queried by a stew about the GPS her first question
was did it have a cd or laser in it.
There's clearly something going on here. I remember the first incident
involved a 757 or 767 that "lost it" for a few seconds and that event was
linked to a passenger with a CD player.
The other issue is that it may not be laser light at all, but certain
frequencies or types of RF that are affecting these systems.
Clearly there is no reason an airline would invest time, effort and money to
enforce a ban on CDs without some justification.
Cya
Bob Denton
Delray Beach, FL
-----Original Message-----
From: Steve Hinksman [mailto:[EMAIL PROTECTED]]
Sent: Monday, August 30, 1999 12:14 PM
Subject: RE: MD: Airborne MiniDisc's? Laser gyros & fuel pumps
debunked
> 747s use laser gyros. A few weeks ago on a flight from
> Johannesburg to Miami
> the pilot explained that "laser radiation" can interfere
> with the gyros and
> in one case, shut down three engines by switching off the
> fuel pumps. I
> know these guys away from the "office" and I don't suspect
> it was bs.
Ummm, how can I put this? Are they on 'ludes?!!!
I work as a designer of simulations for aerospace systems.
We have intimate knowledge of how aircraft systems are
integrated - we have to, we basically re-create the aircraft
as computer code. Personally, I've worked on a 747-400, and
most recently an A320. This just can't happen.
Laser ring gyros are self contained units. There is no
way the laser radiation from a (very broken!) MD or CD
player could get to them in the avionics bay under the
business/first class section on the main level. The laser
light would have to get out of the MD/CD player, pass through
the floor, pass through the gyro box, and pass through
the internal sealed portion of the laser ring part of
the gyro. If the laser can get through all of that,
you were dead a long time ago.
Anyway, laser ring gyros are extremely robust units
that rarely fail, and tend to just shutdown like any
piece of failed electronic equipment. They certainly
won't take out an entire fuel system going down.
Cd players can put out RF interference. RF interference
can affect any piece of equipment, but if your CD player
puts out enough RF to take out a non-RF transmission/reception
device (like a laser gyro), then you should be worried
about what the heck its doing to you!
There is no way the fuel pumps are controlled by whether
or not the aircraft knows where it is. The only fuel pumps
controlled in even remotely such a manner would be the center
tank (and possibly tail tanks) fuel pumps, which are usually
auto-shutoff during takeoff and landing to avoid single
source contamination issues. This is determined by flap/slat
position and weight-on-wheels conditions.
Maybe these guys believe the story, but there's no way
a laser gyro failure could do that.
All the best,
Steve (back to deep lurk mode)
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