Metric system VS .......

[Troyskie]

Ironically, aside from former Eastern Bloc countries, most of the world of aviation are still using British (nautical) Imperial for airspeed and alitiude, however many ground distance requirements are in metric.

In the 70's a Fokker F27 (Friendship) had a fuel miscalculation which in turn caused a weight and balance issue with passengers and cargo. The reason was the weight and balance was in lb, fuel in USG for the aircraft charts, was weight and measured in kg & litres from the ground, and had metric instruments for flight profile.

Each total had to be converted three times, by different people using different methods.

Amazingly the calculations balanced and the aircraft took-off, flew for a while then had to make an emergency landing once it burnt enough fuel off for the weight and balance to go out of whack.

This is still an issue today. I routinely have to convert imperial to metric. Fortunately most of the conversions are just one type of imperial to metric and reverse.

An interesting benefit to imperial is knots to miles (nautical) to time, and degrees of direction.

60kts is 1 mile (nautical) per minute (120=2, 180=3, 240=4, 300=5). I often cruise at around 90kts, which is an easy 1.5 multiple.
1 second of arc on a great circle around the earth is 1/60th of a mile (nautical)
1 minute is 1 mile.

Same can also be said in metric for speed, 60km/h is 1km per min etc. But in aviation 1kt is 1.8km/h.

[balky1]

Ironically, aside from former Eastern Bloc countries, most of the world of aviation are still using British (nautical) Imperial for airspeed and alitiude, however many ground distance requirements are in metric.

In the 70's a Fokker F27 (Friendship) had a fuel miscalculation which in turn caused a weight and balance issue with passengers and cargo. The reason was the weight and balance was in lb, fuel in USG for the aircraft charts, was weight and measured in kg & litres from the ground, and had metric instruments for flight profile.

Each total had to be converted three times, by different people using different methods.

Amazingly the calculations balanced and the aircraft took-off, flew for a while then had to make an emergency landing once it burnt enough fuel off for the weight and balance to go out of whack.

This is still an issue today. I routinely have to convert imperial to metric. Fortunately most of the conversions are just one type of imperial to metric and reverse.

An interesting benefit to imperial is knots to miles (nautical) to time, and degrees of direction.

60kts is 1 mile (nautical) per minute (120=2, 180=3, 240=4, 300=5). I often cruise at around 90kts, which is an easy 1.5 multiple.
1 second of arc on a great circle around the earth is 1/60th of a mile (nautical)
1 minute is 1 mile.

Same can also be said in metric for speed, 60km/h is 1km per min etc. But in aviation 1kt is 1.8km/h.

And to add some fuel to the fire, km/h is not actualy an SI unit, it is m/s (meter per second). Convert knots to that!   
Ivan

[the fan]

My last intern was a student from Maklár Hungary.

Very smart kid but he could never get the hang of the Metric-Imperial differences.

Toward the end of his stay he was writing reporting out on his project and in frustration asked why the hell we didn't use the metric system exclusively like the rest of the world...

With a straight face I explained to him that the metric system was the reason the US was so successful globally. Our methods of measuring take serious mathematical and memory skills and furthermore go a long way in preventing theft of our designs and technology. The highly complicated Imperial system was simply a tool to exercise our minds, no different from exercising in a gym built stronger bodies.  Simply put the metric system was basically math for dummies and the weak minded.

Pretty sure Akos was buying it right up to the point where one of my engineers pointed out that when we decide to annex Europe, our first means of control would be to cut off one finger from every citizen, rendering them incapable of math...

[Troyskie]

Well Balky you beat me to SI units.

m/s to kts is easy, 1m/s is about 1.94kts, so use 2 as an easy multiplier from m/s.

Fan, for your intern, we have Drop Bears in Australia......

[balky1]

Well Balky you beat me to SI units.

m/s to kts is easy, 1m/s is about 1.94kts, so use 2 as an easy multiplier from m/s.

Fan, for your intern, we have Drop Bears in Australia......

Good job! I'd need a piece of paper and a pen to convert that. 

Ivan

[PaulG]

In the 70's a Fokker F27 (Friendship) had a fuel miscalculation which in turn caused a weight and balance issue with passengers and cargo. The reason was the weight and balance was in lb, fuel in USG for the aircraft charts, was weight and measured in kg & litres from the ground, and had metric instruments for flight profile.

In 1983 an Air Canada flight from Montreal to Edmonton ran out of fuel for the same reason.  The pilots did the impossible and performed a dead stick landing at a decommisioned AFB with no control tower, saving everyone.  I remember when it happened and was huge news at the time.

From an episode of Mayday (which is what they called it here).

Just as interesting was the life of the airplane after this :  Gimli Glider