enter image description here

Is this image showing 18.5 liters or quart of engine oil?

  • $\begingroup$ Welcome to Aviation.SE. Could you edit your question and add the type of aircraft you are asking for? $\endgroup$ Sep 26, 2018 at 7:39
  • $\begingroup$ Thanks. I edit it to A320. Eng Cfm 56-5B $\endgroup$ Sep 26, 2018 at 7:56
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    $\begingroup$ It's right there on the screen. It says OIL and right below it it says QT. Probably more obvious to an American who is used to this archaic unit of measure, but the F. USED label is also identified in KG right above it... $\endgroup$
    – FreeMan
    Sep 26, 2018 at 19:09

1 Answer 1


The answer is actually in the image: Below "OIL", it says "QT", which according to the "Abbreviations" table under "General Information" in the A320 FCOM, means

Quart (US)

enter image description here

  • $\begingroup$ Thanks You. You are great $\endgroup$ Sep 26, 2018 at 8:56
  • $\begingroup$ Probably they use this unit because as it is close to liter (0.94), they don't have to change anything for the european market, except the label. $\endgroup$
    – Legisey
    Sep 26, 2018 at 13:12
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    $\begingroup$ @Legisey I think the European market also uses quarts, not liters. It wouldn't make sense for a European made plane which is used by airlines around the globe and potentially flies intercontinental with pilots from all over the globe to have separate displays for different markets, especially in the risky manner you describe where they only replace the unit but don't redo the calculations. $\endgroup$
    – Nzall
    Sep 26, 2018 at 13:31
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    $\begingroup$ A bigger question is why do they use US Quarts for oil? Or more broadly how have we ended up with such a mix of US and metric units (and possibly imperial for all I know). I was going to ask but it's too close to Why doesn't the aviation industry use SI units?, thoughg the accepted answer there states Non-SI is only used for altitude, distance and speed except in US and some other American countries. which doesn't seem to be the case here $\endgroup$
    – Chris H
    Sep 26, 2018 at 13:59
  • $\begingroup$ Yes. The capacity of tank for overflow oil is 20.1 quart. And why i uplift full oil, it only show 18.5. There are logical about it? $\endgroup$ Sep 26, 2018 at 14:26

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