When converting metric units into imperial units, journalists (or more likely sub-editors) are apt to make mistakes, especially if they are dealing with subjects with which they are not very familiar. On the 9th December 2006, The Times managed a hat-trick of blunders. [article contributed by MV]
Page 8 â?? Airlines â??should pay full cost of their pollutionâ??
The penultimate paragraph contained the text â??[Boeing and Airbus] Aircraft use an average of four litres of fuel per 100 kmâ??. This sentence should have raised the alarm bells â?? a consumption of 4 L/100 km is what one would expect of an economical car such as the Smart Car. (The imperial equivalent is 70 mpg!). If the writer used metric units when driving they would have spotted this howler.
Page 43 â?? Why the Dead Sea is dying
The fifth paragraph contains the phrase â??â?¦ to suck 1,900 million cubic metres (2.1 million cubic yards) of water â?¦â??. This phrase contains two howlers. Firstly, a factor of 1000 seems to have gone missing. Secondly, the writer appears to have used a factor of 1.1 to convert cubic metres to cubic yards when the correct factor is 1.1Ã?1.1Ã?1.1 (which is equal to 1.331).
Page 44 â?? Spend a penny, but it make you think of a tenor
The third paragraph contains the sentence â??The block, in Calcutta, is spread over 3,000 square metres (3,300 square yards) and is â?¦â??. Here, the writer used a factor of 1.1 to convert square metres to square yards. The correct factor is 1.1Ã?1.1 (which is equal to 1.21).
Arguably, howlers in the Times don’t matter very much, but they are symptomatic of the British problem of innumeracy and incompetence resulting from the “very British mess” of trying to use two incompatible systems of measurement at the same time. UKMA contends that the only way to resolve this problem is for the Government to grasp the nettle and phase out imperial measures completely and standardise on metric units for all legal and official purposes.
Hi,
You mentioned the Howler on airline pollution.
Would you happen to know how much CO2 a commercial airliner produces into the atmosphere?
Each engine burns about 1.25 tons of aviation fuel.
CO2?
Thank you very much
Regards
Harry
I’m interested in knowing how Harry Vanduyne got his figures and wether this is an example of a howler.
If each engine burns 1.25 tons (Imperial Long Ton? US Short Ton?) then over what period? 1 hour? The lifetime of the engine? I did find one site which quoted “average 3 metric tonnes per hour”. I read that the Long Ton is usually used for aviation fuel but none of these figures match. Is this a problem with our understanding of aviation fuel or part of the mess we get into when we mix units about?
I remember asking the BBC a similar question when they quoted the fuel consumption of the space shuttle in gallons several years back. I asked “US or Imperial? Can you tell us in Litres please” and all they said was “We’re just using a unit that people understand”. They never did answer my question!
I seem to recall that the fuel used PER PASSENGER by a jet airliner is comparable to the fuel used PER PASSENGER in a motor car (the Times journalist probably forgot the “per passenger� part of the figures). The only difference is that I cannot drive from the United Kingdom to Germany for a business meeting, attend the meeting and drive back in the same day – if I did not have access to an aircraft seat, I would probably think twice about attending the meeting.
How much CO2 is produced by an airliner (or a motor car)? If one uses metric units, the calculation is quite simple:
Assume that:
One litre of petrol, diesel or aviation fuel has a density of the order of 0.8 kg/L.
All hydrocarbon fuels are made up of hydrogen and carbon in a ratio of 2:1
All the carbon is converted to CO2 and all the hydrogen to H2O
Carbon has an atomic weight of 12, hydrogen an atomic weigh of 1 and oxygen an atomic weight of 16
Then 14 kg of fuel will produce 44 kg of CO2.
This means that 1 kg of fuel will produce 3.1 kg of CO2 and that each litre of fuel will produce 3.9 kg of CO2.