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RISKS-LIST: RISKS-FORUM Digest Sunday 21 May 1989 Volume 8 : Issue 72

FORUM ON RISKS TO THE PUBLIC IN COMPUTERS AND RELATED SYSTEMS ACM Committee on Computers and Public Policy, Peter G. Neumann, moderator

Contents:

Air Force Bombs Georgia (henry cox) The Geomagnetic Storm of 13 March 1989 (Brian Randell) Tolerability of Risk (Martyn Thomas) More magnetic stripe woes (Joe Morris) Dive Computers revisited (Henry Cox)

The RISKS Forum is moderated. Contributions should be relevant, sound, in good taste, objective, coherent, concise, and nonrepetitious. Diversity is welcome. * RISKS MOVES SOON TO csl.sri.com. FTPable ARCHIVES WILL REMAIN ON KL.sri.com. CONTRIBUTIONS to RISKS@CSL.SRI.COM, with relevant, substantive "Subject:" line (otherwise they may be ignored). REQUESTS to RISKS-Request@CSL.SRI.COM. FOR VOL i ISSUE j / ftp KL.sri.com / login anonymous (ANY NONNULL PASSWORD) / get stripe:<risks>risks-i.j ... (OR TRY cd stripe:<risks> / get risks-i.j ... Volume summaries in (i.j)=(1.46),(2.57),(3.92),(4.97),(5.85),(6.95),(7.99).

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Date: Thu, 18 May 89 10:49:24 EDT From: henry cox <cox@rand.ee.mcgill.ca> Subject: Air Force Bombs Georgia

[ From the Montreal Gazette, 12 May 1989]

US AIR FORCE PROBES WHETHER TRANSMITTERS CAUSED BOMB TO DROP

Atlanta - US Air Force investigators are examining whether electromagnetic radiation from military transmitters may have caused an F-16 jet to accidentally drop a bomb on rural West Georgia last week, and Air Force official said yesterday.

The possibility of electromagnetic interference, however, is only one of several potential causes the Air Force and Army is investigating, said Dee Tait, an official at Moody Air Force Base where the F-16 is stationed. A final accident report won't be ready for 30 to 90 days, she said.

No one was injured in the May 4 explosion, but the 230 kilogram bomb ripped through a wooded area and has prompted a Georgia congressman to call for a review of Air Force flight procedures state wide.

According to forces officials, the inadvertent bombing occurred when one of four armed jets from the 247th Tactical Fighter Wing at Moody was training last Thursday over Fort Benning's "Kilo Impact Area" in Muscogee County.

The pilot of the plane, who has not been identified, tried to release a bomb over the practice range, but it would not drop. As the pilot circled back over Marion County, the bomb fell and its 90 kg of explosives shook windows of houses 900 metres away.

[ Short explanation of EMI causes deleted ]

It [ EMI ] has been attributed to navigation problems with the Army's UH-60 "Black Hawk" Helicopter, which has been banned from flying near 100 transmitters worldwide.

In the case of the F-16, high levels of electromagnetic radiation can accidentally detonate electro-explosive devices, or EEDs, that release bombs, missiles and fuel tanks from the underside of the plane, according to an Air Force {\it Explosive Safety Standards} manual obtained by the Macon {\it Telegraph and News}.

The vulnerability of Air Force planes with EEDs has become and issue at Robins Air Force Base near Warner Robins, Ga., where the Air Force has been shutting down part of the high-powered PAVE PAWS radar station every time and EED-equipped plane lands at the base.

The Air Force operates four PAVE PAWS facilities, which use radar powerful enough to probe objects in space. A current study at the Robins base is examining the power of the pulsed radar beams from PAVE PAWS and whether it disrupts ultra-sensitive electronic equipment on aircraft.

The partial shutdowns preceded a March 1988 Air Force report that stated "the high power contained in PAVE PAWS pulses may pose a danger to elecro-explosive devices carried on military and commercial aircraft."

Tait confirmed that the F-16 [involved in the incident ] had been equipped with EEDs, tiny explosive charges that release the shackles that hold the bomb onto the jet. "They are looking into that," she said. However, she added, "the bomb-release mechanisms on F-16s are designed to preclude electromagnetic interference."

Henry Cox (cox@pike.ee.mcgill.ca)

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Date: Tue, 9 May 89 18:51:04 BST From: Brian Randell <Brian.Randell@newcastle.ac.uk> Subject: The Geomagnetic Storm of 13 March 1989

A colleague drew my attention to an article in Radio Communication (Vol. 65, No. 5, May 1989), which made me realise belatedly just how vulnerable we are to the effects of magnetic storms. Below I excerpt from the article, without permission.

THE GEOMAGNETIC STORM OF 13 MARCH 1989

Ted Harris and David Kerridge, Geomagnetism Group, British Geological Survey, 29 March 1989.

"The largest magnetic storm for 40 years started at 2am on 13 March 1989... The intensity of the storm was such that the aurora borealis (northern lights), normally restricted to high latitudes, was seen clearly in the south of England, and there were reports of observations of the aurora in Italy and as far south as Jamaica.

"The rapid changes in the geomagnetic field during the storm induced voltages in power lines, transoceanic cables, and telephone and cable TV networks. In Quebec, transformers in the Canadian electricity supply tripped, blacking out large areas of the Province and plunging more than a million people into darkness. (No doubt with a consequential blip in the birth-rate in nine months time!)

"Ionospheric disturbances caused disruption of radio communications and resulted in the loss of TV reception in some areas. Satellite communications were also affected - as were satellite orbits as the increased ionospheric density produced extra drag.

"The increased radiation at high level created such potential hazards that a Concorde airliner on a transatlantic route took a more southerly flight path to avoid subjecting its passengers to radiation. Astronauts aboard the the space shuttle `Discovery' would have been prevented from working outside the space craft because of the danger. The shuttle mission was recalled a day earlier than planned because of computer malfunctions which could have been caused by the storm.

"At sea-level, North Sea exploration companies reported that `down-well' instruments, used to steer drill heads, had experienced violent swings in compass readings of up to 12 degrees! A Norwegian geophysical exploration company reported that all surveying has been halted after receiving warnings of the storm and its severity from GRG. The director of operations reported that two navigation systems used to fix the position of survey ships, which were in agreement prior to the storm, were now diverging. GPS (Global positioning system) satellites experienced increased drag which retarded their orbits so much that positional accuracy at the Earth's surface was lost. ...

"Solar activity is likely to peak during 1990 (Solar Maximum), resulting in more magnetic storms and a generally high level of magnetic activity over the next two years at least."

Brian Randell, Computing Laboratory, University of Newcastle upon Tyne

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Date: Wed, 17 May 89 14:55:43 BST From: Martyn Thomas <mct@praxis.UUCP> Subject: Tolerability of Risk

I strongly recommend the publication The Tolerability of Risk from Nuclear Power Stations, Health and Safety Executive, Her Majesty's Stationery Office, December 1987. It contains a thorough discussion of the way in which society perceives, and tolerates, risks from different sources. It also contains interesting UK actuarial statistics (...in Britain, a man of 20 has roughly a 1 in 1000 chance of dying in a year, for a man of 40 it is 1 in 500, at sixty, it is 1 in 50 for a man, 1 in 100 for a woman ...).

There is a companion volume of comments received from trade and professional groups. -- Martyn Thomas, Praxis plc, 20 Manvers Street, Bath BA1 1PX UK. Tel: +44-225-444700. Email: ...!uunet!mcvax!ukc!praxis!mct

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Date: Fri, 19 May 89 09:21:12 EDT From: Joe Morris (jcmorris@mitre.arpa) Subject: More magnetic stripe woes

Quick background: the Washington area Metro subway system uses fare cards with a magnetic strip on the back. You buy a card of some particular value; it is debited as it is used (the fares are distance-sensitive) and each time you exit Metro the remaining value is recorded *and printed* on the farecard. With this in mind, the following news article appeared in the 19 May issue of the _Washington_Post_, p. C7 (as usual, without permission):

DASH Magnets and Farecards: A Fatal Attraction

Alexandria's DASH bus system [a suburban transit system] thought it was promoting public transit Wednesday when it gave riders 2,500 refrigerator magnets in honor of national "Transit Appreciation Day."

Funny thing, though, how the magnets apparently erased the value of an unknown number of riders' Metro Farecards, officials said yesterday.

"We didn't do it intentionally, and definitely apologize to our passengers for any inconvenience," said DASH General Manager Sandy Modell.

Metro officials said riders can obtain new cards by mailing the now useless ones to Metro's treasurer's office [...].

The number of Farecards affected and the potential amount owed riders was not known yesterday, DASH and Metro officials said.

The value of a Metro Farecard is magnetically encoded when the card is purchased. Cards are scanned electronically when passengers pass them through the fare gates, which automatically deduct the trip fare.

Apparently, the small thin magnets, which fit in wallets and change purses, erased the Farecards when they were stored together, said Metro spokeswoman Beverly Silverberg.

"It happens all the time" when women carry purses with magnetic clasps or riders carry other types of magnets, Silverberg said. Modell warned that magnets can have the same effect on automated teller machine cards and some credit cards.

DASH bought the magnets, which included the DASH telephone number, from the American Public Transit Association, which offered them to transit agencies across the country, Modell said. She did not know if any other systems were similarly affected.

DASH passed out the magnets "as a token of appreciation" to riders, Modell said.

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Date: Thu, 18 May 89 10:48:02 EDT From: henry cox <cox@rand.ee.mcgill.ca> Subject: Dive Computers revisited

Some time ago several submissions dealing with the potential risks of dive computers (which automatically monitor the nitrogen level in the divers blood, and tell him when he must surface, etc.) appeared in RISKS. Since then, I acquired one myself. My experience might be of interest to others.

Soon after Christmas, two friends and I purchased three Oceanic Datamaster II (a particular brand) dive computers. At the same time, we also purchased "Slimline" compasses, which were designed to fit into the same console. All of the units (three of three) were eventually returned due to defects:

1) Due to electromagnetic interference, when the computer was ON, the compass would point in whichever direction the console pointed - making completely useless.

2) One unit was broken when shipped (or was broken during shipping), and never worked at all.

3) Among other features, the computer was supposed to report the "dive time remaining", based on air consumption and no-decompression nitrogen levels - whichever is less. On one unit, this was not recomputed correctly - stuck on 29 minutes, even when there was no air left in the tank it was connected to. (Yep, I'll just sit here and hold my breath for 29 minutes...)

4) The last unit appeared to work correctly when checked out in the pool, but failed completely on its first real dive, giving no readings at all.

All three units were returned and replaced with and upgraded model, the Datamaster Sport - all three of which have worked properly to date. The EMI problem was fixed with a redesigned console boot, which moved the compass further away from the computer.

Certainly, some of these problems should have been caught and corrected by the manufacturer (Oceanic USA, inc.) - particularly the EMI interference on the compass, which would have been obvious to anyone who turned the unit on and tried to use it. The other problems MAY have been caused by shipping, although I doubt it, as the cartons arrived undamaged. In any case, presumably the unit will be subjected to some rough handling during use, and should be designed handle it.

I think that the real problem here was improper and incomplete testing of the product before it was shipped out the door - potentially, a VERY serious RISK, given the nature of the activity is designed for.

As has been stated many times before, computer readouts are no excuse to turn off your brain, and it is not wise to rely on any one instrument. In my case, I dive with two complete sets of gauges (my old set plus my dive computer), and I continue to work out nitrogen levels for myself. Doing otherwise would be very foolish.

Henry Cox

DISCLAIMER: I have NO CONNECTION whatsoever with OCEANIC USA or any other dive equipment manufacturer (except that I own some of their equipment). The opinions stated above are my own. The events which inspired them are also mine (unfortunately).

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End of RISKS-FORUM Digest 8.72 ************************