mangogrooveworkshop
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| posted on 3/12/10 at 05:41 PM |
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never mix metric and imperial...it will end in tears
In response to conrod kids very valid line read this ......... http://en.wikipedia.org/wiki/Gimli_Glider
Two Guys, a 767 and a Calculator
One of the most famous aircraft that ever took to the skies (next to The Memphis Belle, The Enola Gay and The Spirit of St. Louis) was The Gimli
Glider. Because on July 23, 1983 - a very memorable day for the racing enthusiast who gathered in Gimli, Manitoba, just north of Winnipeg veteran
pilots – Bob Pearson and Maurice Quintal, in the cockpit of Air Canada Flight 143, made one of the greatest “dead stick” landings in history. Thus
began the legend of The Gimli Glider.
The aircraft was a new Boeing 767 and because of a mistake in fuel calculation (Canada had yet to convert all measurements to metric) the big jet was
under-fueled. When the fuel ran out Pearson glided the 767 at 220 knots with Copilot Quintal began making glide-slope calculations to see if they’d
make Winnipeg but he calculated that Winnipeg was going to be too far. He advised Pearson to turn north to Gimli, the site of an abandoned Royal
Canadian Air Force Base around 12 miles away.
Drag Strip Runway
Quintal was familiar with Gimli because he’d been stationed there during his time in the Canadian Air Force. However, unknown to him and the air
traffic controllers in Winnipeg, the 6800 foot runway he chose was now being used for auto racing and a steel guard rail had been installed down most
of the southeastern portion dividing it into a two lane dragstrip.
This just happened to be “Family Day” for the Winnipeg Sports Car Club with go-cart racing for kids. Parked around the sides were dozens of cars,
campers, kids, and families.
Front Wheels Don’t Lock Down
The Ram Air Turbine, a propeller driven hydraulic pump tucked under the belly of the 767 are supposed to supply hydraulic pressure to move the control
surfaces and enable a dead-stick landing. So down came came the landing gear – almost. there was not enough pressure so a manual override was
attempted right out of the manual. The main gear came down but not the nose gear. As it landed two tires blew with explosive force as Pearson jumped
on the brakes. Then the unlocked nose gear gave away and the giant aircraft sprayed a shower of sparks as the nose skidded on the tarmac. Luckily
everyone cleared away and no one on the 767 was injured.
A commander of one of the space shuttle flights said later, “It was one of the greatest dead-stick landings in history.”
In a few days Air Canada Aircraft #604 was repaired enough to be flown out of Gimli. After approximately $1,000,000 in repairs #604 started back on
its schedule and flew without incident until its forced retirement on January 24, 2008.
The Boeing 767 – Canadian air registration C-GAUN – is now parked in the desert.
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Bluemoon
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| posted on 3/12/10 at 06:26 PM |
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NASA also have had similar issues:
http://en.wikipedia.org/wiki/Mars_Climate_Orbiter
http://articles.cnn.com
/1999-09-30/tech/9909_30_mars.metric.02_1_climate-orbiter-spacecraft-team-metric-system?_s=PM:TECHhttp://en.wikipedia.org/wiki/Mars_Climate_Orbiter
quote:
The navigation error arose because Lockheed Martin, the contractors for the craft's thrusters, did not use SI units to express their
performance[1][
quote:
The metric/US customary units mix-up that destroyed the craft was caused by a human error in the software development.[1] The thrusters on the
spacecraft, which were intended to control its rate of rotation, were controlled by a computer that underestimated the effect of the thrusters by a
factor of 4.45. This is the ratio between a pound force (the standard unit of force in the United States customary units system) and a newton (the
standard unit in the metric system). The software was working in pounds force, while the spacecraft expected figures in newtons; 1 pound force equals
approximately 4.45 newtons.
Lost one of the departments instruments the Pressure Modulated Infrared Radiometer (PMIRR) (lost well may be more like smashed to bits on mars!)
because of these issues...
The space craft only cost $125Millon...
Dan
[Edited on 3/12/10 by Bluemoon]
[Edited on 3/12/10 by Bluemoon]
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LBMEFM
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| posted on 3/12/10 at 06:53 PM |
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Amazing landing of the Boeing, very interesting.
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Ninehigh
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| posted on 3/12/10 at 08:16 PM |
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I'd heard of a swimming pool being built many years ago, they started one end in metric the other in imperial and none of it matched up. Not as
bad as the above though
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SteveWalker
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| posted on 3/12/10 at 10:20 PM |
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quote:
Originally posted by LBMEFM
Amazing landing of the Boeing, very interesting.
If you ever watch Air Crash Investigation, this features in one of them.
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BenB
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| posted on 4/12/10 at 10:53 AM |
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Ah you should see the dead sticks landing I did the other day, it was a bute  Still haven't worked out why my poxy engine keeps on cutting out
mid flight (though I'm getting closer to the cure by a process of elimination!). Luckily I was on the ground twiddling the r/c sticks not in the
plane
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prawnabie
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| posted on 4/12/10 at 11:04 AM |
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The where a number of errors that caused that crash really, people misunderstanding that there where told, mechanics being distracted and a very
revised makeshift manual.
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zilspeed
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| posted on 4/12/10 at 12:01 PM |
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I mix metric and imperial all the time.
"That job will need 50m of 4x2."
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