European regulators are looking into alternative measures to mitigate an apparent safety risk relating to Boeing 727 auxiliary fuel tanks, after opting not to adopt a US FAA directive on the matter.

The directive, to which Boeing had objected, argues that the fuel-quantity indicating system presents a potential electrical ignition source, and orders operators to modify the system or de-activate the tanks.

But the European Union Aviation Safety Agency says it is “not in possession of sufficient data” which would allow it to determine whether an unsafe condition exists, and therefore support proportionate corrective measures.

“Consequently, there is insufficient justification to warrant the actions as required by [the US directive],” it adds. The directive is due to take effect on 4 February.

EASA says, however, that it is considering possible alternative actions to mitigate any safety risk for aircraft operating under European regulations.

It has not indicated how many 727s with auxiliary tanks fall within this jurisdiction but states it will co-ordinate with the design approval holder and the FAA, in order to obtain additional data.