An ongoing trial of a jet fuel additive by KLM and Shell Aviation has shown that the AeroShell Performance Additive 101, originally developed for the US Air Force, can provide commercial aircraft operators with fuel economy, maintenance and emissions benefits.

The trial is intended to build a commercial case for the additive, which has already attracted interest from a number of airlines, says Shell Aviation.

Additive 101, developed by BetzDearborn and marketed and distributed outside of the USA by Shell Aviation, is a high temperature dispersant or detergent that is designed to keep fuel and injector systems clean, reduce exhaust emissions, improve fuel efficiency and cut maintenance costs.

The additive was developed for the USAF for its Lockheed Martin/Boeing F-22s, but its high thermal stability has also led to use in USAF Boeing F-15s and Lockheed Martin F-16s, says Dr Mike Farmery, Shell Aviation technical and quality manager. Use of the additive has reduced fuel fouling of engine components by 90%, while unscheduled engine removals due to fuel-related malfunctions have been cut by 50%, according to the USAF. The Danish air force is also using the additive, while the Australian, Chinese, Greek and Norwegian air forces are evaluating it.

Early last year KLM launched a trial to determine the additive's commercial benefits, with two General Electric CF6-80-powered Boeing 747-400s operating from Amsterdam Schiphol to Singapore and Bangkok.

Farmery concedes that, due to the sophistication of airliner engines, fuel economy benefits are likely to be minimal, but maintenance savings are expected. The greatest benefit to the civil market will be reduced emissions, he says. In the long term, if the additive allows better thermal stability, engines could be designed to run hotter and more efficiently, he says.

Farmery concedes that it has been difficult to get measurements of emissions during the trial, but laboratory analysis shows "positive trends", including "a significant reduction in the number and size of particulates". Empirical data is also expected from tests next month as part of the European Commission-funded Partemis study, which is measuring and predicting the emission of aerosols and gaseous precursors from gas turbine engines.

A number of airlines are expressing "strong interest" in Additive 101, including Japan Airlines and Lufthansa, says Farmery, adding that Polar Air Cargo is keen to conduct a trial. Additive 101 has also sparked interest in performance-enhancing fuel additives, including cold flow additives that will be needed for new polar routes.

Source: Flight International