-
Computers cause electronic cat flap latch to
malfunction. Computers used in a room close to a door fitted with a
high-technology (magnetic) cat flap caused the latches on the cat flaps
to rattle continuously whenever Windows was loaded or a Windows application
run. (From the New Scientist magazine, 7th May 1997)
-
Uncommanded operation of powered Wheelchairs.
The U.S. Food and Drug Administration's FDA Consumer Magazine
May 1995 reported that a man in a powered wheelchair was seriously
injured when his chair rode off a cliff at high speed. He was several miles
from a radio tower and three blocks from a busy road, where mobile radios
were likely in use. The FDA subsequently tested powered wheelchairs in
its laboratories after receiving reports of a number of other malfunctions
and found that the wheelchairs' brakes would release and the wheels would
begin turning in relatively low-strength electromagnetic fields. A police
radio held about a meter away (3 feet, 4 inches) could cause some wheelchairs
to move.
-
Residents in Hobart Tasmania trapped in their garages
when radar on aircraft carrier USS Carl Vinson affected garage door remote
controllers.
"Hobart in Tasmania suffered an unusual blight earlier this month.
Residents all over town found themselves trapped in their garages when
the remote controls that operate the garage doors suddenly failed to function.
Roll-a-door companies were flooded with calls from angry garage owners
and were at first completely nonplussed by the problem. Then the explanation
emerged: the aircraft carrier USS Carl Vinson had just cruised majestically
into the town’s docks, equipped with navigational radar employing the same
frequency as the remote controls for the town’s garage doors. According
to the local newspaper The Advocate, an apologetic Lieutenant Dave Waterman,
the ship’s public affairs officer, said that the problem would only occur
when the ship was arriving and leaving." (New Scientist, 24th April 1999,
page 100)
-
Geomagnetic storm blacks out Quebec
Every 11 years violent storms on the surface of the Sun cause massive
amounts of energy – in the form of protons and electrons – to be thrown
out into space. After a few days, this energy reaches Earth, interferes
with the planet’s magnetic field and generates huge currents – particularly
in the polar regions. These induced currents can subsequently induce massive
surges in (power distribution) transmission lines, damaging transformers
and causing high-amplitude harmonics. In the space of just 2 minutes in
March 1989, six million people in Quebec, Canada, suffered a complete blackout
because of a severe storm from space. In the UK the problems were less
severe, but some were experienced (see Electrical Review, 20 July 1999).
-
NASA Reference Publication
1374 “Electronic System Failures and Anomalies Attributed to
Electronic Interference” July 1995 lists a number of non-space
examples of electronic system failures, for example:
-
Uncommanded release of munitions from a Navy
jet landing on the aircraft carrier U.S.S. Forrestal off the coast
of Vietnam (1967) struck a fully armed and fuelled fighter on the deck.
The results were explosions and the deaths of 134 sailors and severe damage
to the carrier and aircraft. This accident was caused by the landing aircraft
being illuminated by carrier-based radar and the resulting EMI sent an
unwanted signal to the weapons system. (Source: NASA)
-
A DC 10 Autopilot was disrupted during
final landing approach by a battery-powered CD player operated by a
passenger in first-class in February 1993. To prevent the aircraft from
crashing after suddenly veering off course, the pilot had manually to take
control. (Source NASA)
-
Black Hawk Helicopter knocked out of the sky
by radio waves. The Boston Globe 8 November 1987 reported that
"The Army’s most advanced helicopter to carry troops into battle can be
knocked out of the sky by routine radio waves from microwave towers, radio
antennas and radars according to Pentagon officials and documents. Investigators
believe that such radio waves made five of the Army’s UH-60 Black Hawks
nose dive into the ground since 1982 killing 22 servicemen." According
to the Globe, Navy Sea Hawks, which had improved protection against electromagnetic
interference did not appear to suffer from the same problem. Because Electromagnetic
Interference (EMI) leaves no “fingerprints”, the Army has been unable or
unwilling to cite it as a cause of any other 29 Black Hawk accidents that
have killed 48 servicemen since 1980. Shielding the Army Black Hawks to
Navy standards would be “very costly,” Army officials said. [Army Blackhawks
were however later modified.]
-
Chinook Mark II Helicopters experience spurious
engine accelerations and decelerations. April 1994 onwards. Royal Air
Force (RAF) Pilots on British Chinooks fitted with FADEC (Full Authority
Digital Engine Controls) discovered that the Chinook's engines sometimes
accelerated or decelerated suddenly and without warning. A Squadron Leader
at the main UK Chinook depot, RAF Odiham, later told an RAF Board of
Inquiry: "The unforeseen malfunctions on the Chinook HC2 of a flight critical
nature have mainly been associated with the engines control system FADEC.
They have resulted in undemanded engine shutdown, engine run-up,
spurious engine failure captions, warnings in the cockpit and misleading
and confusing cockpit engine indications".
On 2 June 1994, an RAF Chinook Mark 2 helicopter, ZD 576, crashed on
the Mull of Kintyre. All those on board the aircraft were killed in the
crash and the aircraft sustained catastrophic damage. The cause of the
accident was never confirmed, but the RAF Board of Enquiry concluded that
both pilots were negligent. A Parliamentary Select Committee was
appointed to consider the justification for the RAF Board of Inquiry findings
and interviewed expert witnesses. The Select Committee reported that "although
no trace of any mechanical fault, other than a defective radar altimeter,
was found by the Air Accidents Investigation Branch inspector, he was unable
to dismiss the possibility of an undemanded flight control movement, an
engine run up or a control jam having occurred. Any of these events could
have had a serious effect upon the crew's ability to control the aircraft."
They concluded: "we consider that it could not be said that there was absolutely
no doubt whatsoever that some mechanical failure had not caused a loss
of control of the aircraft....It is not our role to determine the likely
cause of this accident, and indeed on the evidence which we have heard
and read it would be impossible to do so. We are nevertheless satisfied,
on the evidence before us and against the standard of "absolutely
no doubt whatsoever", that the Air Marshals were not justified in finding
that negligence on the part of the pilots of ZD 576 caused the crash."
http://www.parliament.the-stationery-office.co.uk/pa/ld/ldchin.htm
http://www.parliament.the-stationery-office.co.uk/pa/ld200102/ldselect/ldchin/25/2502.htm
-
Washington State Ferries replace "sail by wire"
electronic control system with pneumatic controls (IEE Spectrum Vol 27,
no 2 February 1990 page 54. The six ferries in the Issaquah class fitted
with electronic control systems suffered a series of intermittent faults
- ferries rammed docks or moved away from them even though no commands
were given. In some instances a ferry shifted from forward to reverse with
no warning. Eventually the ferries were retrofitted with hybrid electro-pneumatic
control systems and, since then have performed flawlessly. The problems
were caused by shoddy electronic control system design.
|