ATR 72 turboprop operators are to be instructed to modify fuel gauges to ensure that the indicator for the smaller ATR 42 cannot inadvertently be fitted in their place.
Investigators determined that installation of the wrong gauge on a Tuninter ATR 72 resulted in the pilots being misled over the quantity of fuel in the aircraft.
The turboprop suffered fuel exhaustion while en route from Bari to Djerba in August 2005, forcing its crew to ditch off the coast of Sicily with the loss of 16 lives.
"Overruling standard operational procedures and maintenance practices have led to this kind of occurrence," says the European Aviation Safety Agency in a directive proposal.
"Consequently additional actions to help avoid maintenance errors...need to be taken."
While the ATR's fuel-indicating system complies with requirements, says EASA, such errors would be "mitigated" by making it "mechanically impossible" to install an ATR 42 gauge in the larger variant.
EASA is preparing an instruction to operators to modify the indicator on ATR 72-100s and -200s by installing a locking adaptor on the electrical connector.
Aircraft which already have a secondary low fuel-level detection system fitted will need to be modified within three years; those without in just two.
EASA is still consulting on the proposed directive and is inviting comments until 20 February.