|Kurt H. Strauss has been involved in aviation fuel development and standardization for over 50 years. During most of that time he has been an active member of ASTM International. His activities have included officer roles in Committee D02 on Petroleum Products and Lubricants as well as D02 Subcommittee J on Aviation Fuels; he also developed and has presented the ASTM aviation fuel training course all over the world.
Technical and Professional Training for Aviation Fuel
Another influence on the aviation community is the ASTM technical training course on aviation fuel. Since its inception in 1995 the course has been presented over 100 times to more than 2,000 attendees. These students have been exposed to the details of specifications, test methods and quality control procedures and have inspected airport fueling systems all over the world. Locations have included the United States, Canada, Central America, Europe, South Africa, the Middle East and Far East. Repeat sessions have been presented in Indonesia, Hong Kong, Singapore, Kuwait, Bahrain, Hawaii and less exotic places such as Philadelphia, Pa., and Los Angeles, Calif. Students have left the course with a better understanding of aviation fuels as well as the role of ASTM International in their industry.
||From Argentina to Zaire
Aviation Fuels Get You There Safely
Taking off in New York, topping off the tanks in the Pacific and landing and refueling in Australia is a complicated matter made simpler and safer for passengers by ASTM International’s standards for the buying, selling, testing and certifying of aviation fuels.
Right from its beginnings aviation has had an international flavor. In fact, the first long-distance flight over water by Louis Bleriot in 1909 was from France to England.
But we are getting ahead of ourselves because fuel development was local in its early days. There was no standardization then because all internal combustion engines, whether in cars, airplanes or boats, ran on the same uncontrolled gasoline. Not until aircraft became more sophisticated in the 1920s were there separate fuels for this use. In the 1930s, aviation gasoline improvement was accelerated by the use of tetraethyl lead, which in turn spurred the concurrent development of engines and fuels. The U.S. Army recognized this process by issuing the early aviation gasoline specifications, civil aviation being relatively insignificant in those days.
Interestingly, these military aviation gasoline specifications did not allow for geographical or climatic effects at a supply point but instead required that all aircraft and their engines operate on the same volatility all over the country, regardless of ambient temperatures. This approach acknowledged that aircraft could move readily from one region to another and would have to be able to start and operate at those locations.
The policy caused manufacturing problems for refiners and design difficulties for aircraft manufacturers, but ultimately simplified supply logistics, particularly when international flight became a reality. It also melded fuel and aircraft into a closely interrelated system that did not allow either side to make major changes without affecting the other side.
Passenger-carrying aviation started in the late 1930s, got a big push during World War II and really took off after that. As its earliest effort in aviation fuels, ASTM Committee D02 on Petroleum Products and Lubricants issued a civil aviation gasoline specification in 1944 but tabled it under wartime conditions. Specification development resumed with the publication of D 910, Specification for Aviation Gasolines, in 1947. This specification, though modified over the years, is still used today.
The importance of this specification cannot be overestimated. All U.S.-built aircraft, starting in the late 1940s, were certified and required to operate on gasoline meeting the specification. Considering that U.S. aircraft built by Douglas, Lockheed, Convair and Boeing populated not only U.S. airlines but were the mainstay of most foreign airlines, the impact of D 910 becomes apparent.
Although the jet age has supplanted the “piston pounders,” D 910 is still important today because it governs the gasoline burned in general-aviation aircraft. Thus, obtaining compliant fuel assures the pilot that he is operating on fuel that is legally fit-for-purpose. While some other countries may have their own specifications, they are usually mirror images of D 910 and are therefore acceptable to the original equipment manufacturers and air-worthiness authorities.
Like aviation gasoline, aviation gas turbine fuel, more familiarly known as “jet fuel,” had its military ancestry. The preparation of civil jet fuel specifications awaited the commercial introduction of turbine powered transports to U.S. airlines in 1958. ASTM issued D 1655, Specification for Aviation Turbine Fuels, in 1959. As larger aircraft with more powerful engines became available, ASTM continued as the focus for the specification changes necessary to accommodate fuel availability and performance issues.
It goes without saying that the single-specification approach became essential as the scope of commercial aviation expanded internationally in drastic fashion. In turn, civil aviation was able to build on a relationship between the U.S. and Great Britain, both of which had coordinated their military gasoline specifications over the years. Today, ASTM and British civil specifications are closely coordinated, although not identical. The combination is recognized in a Joint Checklist, which combines the most severe requirements of D 1655 and the British specification, DefStan 91-91, so that fuel meeting the check list can be supplied anywhere in the world. Similar international coordination exists for aviation fuel test methods.
Today, ASTM standards D 910 and D 1655 govern most aspects of civil aviation fuels. The specifications and their required test methods control fuel certification and release at the refinery. They facilitate the purchase and sale of fuel because specification compliance satisfies both parties with regard to the acceptability of the product. Ultimately they meet the “satisfactory for use” criterion mandated by airworthiness authorities for safe aircraft operation. ASTM Committee D02 has jurisdiction over both specifications and, equally importantly, develops and maintains the test methods, procedures and guides that define the specification requirements.
All components of the aviation spectrum, including airlines, airframe and engine manufacturers, fuel and additive suppliers, government agencies and independent organizations such as pipeline operators and research institutes are active committee members; the committee roster also reflects the strong international flavor of today’s aviation picture.
To satisfy liability and safety concerns, all aspects of aviation fuels receive an extremely high level of scrutiny, a process not necessarily copied by other industries. Because ASTM aviation test methods are in constant use all over the world, quality check programs such as the ASTM Interlaboratory Crosscheck Program are an important part of the picture.
Quality Control and the Fuels of the Future
Jet fuel’s journey from refinery to aircraft averages 30 days in the United States. Most jet fuel moves through multiproduct pipelines that also transport several grades of motor gasoline, diesel fuel and heating oil. Fuel storage capacity at major airports is between one and three days of operation. There is very little “slack” in this system. Any deviations from the specification requirements that would make a fuel batch unsuitable for use could affect many passengers through delayed or cancelled flights. To avoid such problems an elaborate system of handling procedures, including periodic testing, is in place. ASTM creates the test methods and other information that are part of this quality control system.
ASTM has also become the focus of close cooperation between the U.S. military and civil aviation. To simplify military logistics and to avoid the duplication of test method development, the U.S. military uses only ASTM test methods and attempts to keep its jet fuel performance specifications as close to ASTM specifications as possible. Representatives of military branches participate very actively in ASTM work.
Looking toward the future, two important efforts stand out. The first is the development of a high-octane unleaded gasoline that will satisfy the needs of most existing engines currently operating on high-octane leaded product. A cooperative effort between industry and government agencies is working toward that goal. There are major incentives for getting rid of the last leaded fuel in the petroleum inventory, but finding an acceptable unleaded substitute continues to be a difficult assignment.
The second effort involves the acceptability of jet fuels made from non-petroleum sources, be they coal, natural gas or biomass. Such fuels may have properties making them unfit for use in modern or future aircraft. However, these properties may not be controlled by D 1655, which is based on a long history of fuels made from petroleum crudes. Currently each source for such jet fuels is approved on an individual basis an expensive, time-intensive process. The effort therefore concentrates on the development of a generic process for the examination and acceptability of all such fuels, a process thatis ultimately expected to change D 1655 into a universal specification applying to all jet fuels, regardless of their origin. //