Fuel pump inspection stickers on a pump island at an Aral gas station on the A5 autobahn in Germany indicate inspections on most pumps here are good until the end of 2008, and a couple are good until the end of 2009. (Matt Millham / S&S)
Ever wonder whether the gas ticking off at the pump is actually going into your tank?
More than likely, it’s close enough.
Pumps at Army and Air Force Exchange Service stations are inspected every six months — twice as often as is required by U.S. law, and four times as often as German pumps — in order to ensure accuracy.
These measures aren’t entirely altruistic. While AAFES wants to ensure customers aren’t getting ripped off, making sure the pumps work properly also prevents the exchange from losing money, according to an exchange spokesman.
That doesn’t mean the pumps are perfect.
Every country in Europe and every state in the U.S. allows pumps to be off by some margin.
AAFES pumps can be off by as much as 2.22 ounces per 5 gallons of gas — in either the exchange’s favor or yours — before raising eyebrows. That’s about .06 liters per 20 liters of fuel. In Germany, AAFES pumps are checked by independent maintenance contractors certified by German authorities. AAFES managers also have to monitor their equipment.
U.S. states allow different variations. In Washington, for example, pumps can be off by as much as 3 ounces for every 5 gallons pumped; in Montana, they can be off by about a third of an ounce more than that.
These volumes aren’t huge; we’re talking a difference of about one-third of 1 percent at AAFES.
And more often than not, those errors are in favor of customers, according to both AAFES and weights and measures agencies in the U.S.
Dispenser meters wear out over time, Lt. Col. David Konop wrote in an e-mail. “This wear factor leads to over dispensing; the first clue is daily variances to the inventory that have no logical explanation.”
The exchange hasn’t noticed any pump variances in the last six months, he said. In Germany, about 4.1 percent of the 200,000 pumps inspected on the local economy failed inspections in 2000, according to the European Cooperation in Legal Metrology. In the United Kingdom about 9 percent of the 60,000 pumps checked failed inspection.
But if there are problems with AAFES pumps, those variances are addressed, Konop said.
“Dispensing calibration will be tested any time there are reasons to suspect the flow meters are out of calibration,” he wrote. Customer comments, inventory incongruities or a history of calibration problems are among the things that would warrant such tests.
