## 10 Biggest Mathematical Disasters in the World

October 20, 2009

The millennium bug or the Y2K bug was going to cause planes to fall from the sky, bank accounts to be wiped out, electricity grids to cease functioning, trains to crash, cars to collide as stop lights stopped functioning, life support units to malfunction and computers to crash around the globe. For years leading up to midnight on New Years eve 1999 consults were paid extraordinary amounts of money to solve the problem.  When the clock ticked over to 1st Jan 2000 nothing much happened. It was, indeed, a non-event, an error in logic. (Pic from, appropriately, digyourowngrave.com)

The Maths Error: Guessing the Answer.

Computer programmers represented the year in the date of many programs using two digits but claimed logical errors would arise upon “rollover” from x99 to x00.

While consultants claimed their advice saved the world from catastrophe countries that spent very little on the Y2K bug problem (eg. Italy and South Korea) experienced as few problems as those who had spent a good deal of money on the bug eradication namely USA and UK. The solution: Don’t guess. Test parts of system by plugging in x00.

## 6 Air Canada Flight 143

October 20, 2009

On 23rd July 1983 Air Canada Flight 143, a Boeing 767 ran out of fuel at 41,000 feet (12,000m) altitude, about halfway through its flight from Montreal to Edmonton. The crew managed to glide the aircraft safely to an emergency landing at Gimli Industrial Park Airport, a former airbase at Manitoba. This was some challenge. No fuel means no engines. No engines means no electronics, no steerage, no navigation. An emergency propellor driven dynamo ( similar to that used to produce light on bikes) dropped down on an arm under the plane to produce basic power for steerage. Navigation had to be by sight or calculation of speed etc. That involved some maths, mathspigs. There were no fatalities.

The Maths Error: Oops again! Muddling units of volume!

The first error was that the fuel tank gauge wasn’t working. It was to be replaced in Edmonton. The second error was a maths error. The ground crew filled the tanks according to their records. The fuel requirements were assumed to be in litres but they had been recorded in gallons.(Pic Right : Quarter of a Gallon)

Here it is the metric Vs Imperial problem again. This incident was shown on Air Crash Investigation (or Mayday) Season 5, Episode 6.

## 9 The Quebec Bridge Collapse

October 20, 2009

At five-thirty on the afternoon of August 29, 1907, workers heard a loud retort like a canon shot. Two compression chords in the south anchor arm of the Quebec bridge had failed. The bridge was to have a span of eighteen hundred feet when completed — the longest in the world. It took 15 seconds for the bridge to collapse into the St Lawrence River. 75 workers lost their lives.

The Maths Error: Not Doing the Maths

The span of the bridge was lengthened from sixteen hundred feet to eighteen hundred feet so that bridge pillars could be built for a lower cost closer to the riverbank. In 1903 the Canadian Government provided funding and in the rush to produce drawings so that the steel for the bridge could be fabricated, there was no recomputation of assumed weights for the bridge under the revised specifications. The hierarchy ignored young engineers who expressed concern.

Failure top do the maths also caused the collapse of the West Gate Bridge in Melbourne, Australia, in 1970 killing 35 workers. In trying to connect the main lengthwise splice of the bridge, engineers started removing bolts from the main transverse splice at midspan to correct for misalignment without making appropriate calculations. They removed so many that the bridge suddenly collapsed. To this day travel speeds are controlled on the bridge to reduce the stress load and motorists believe speed limits are for road safety and not because the bridge might collapse!!!!!!!

Footnote: A new design for the Quebec bridge was with a single long cantilever span was produced. It was even heavier than the previous design. On September 11, 1916, when the central span was being raised into position, it fell into the river, killing 13 workers. (Pictured Left.)

Westgate Bridge Picture Left: http://www.jbrown.com.au