Mobil Oil Australia Ltd., an affiliate of ExxonMobil Corp., has found itself embroiled in a public relations nightmare as a result of contamination of the aviation gasoline, or "avgas," product stream from its Altona refinery.
Avgas containing the anticorrosive agent ethylene diamine has grounded a reported 5,000 piston-engine aircraft that used avgas produced in the Altona plant during Nov. 21-Dec. 23, 1999. The planes developed fuel-system deposits as result of the contamination.
Mobil has offered $15 million (Aus.) in compensation to the affected parties, but lawyers and aircraft operators estimate the losses at closer to $50 million/month.
The Civil Aviation Safety Authority (CASA) has issued a no-fly order covering aircraft that had been supplied with avgas from Mobil's Altona refinery in Melbourne since Nov. 21. This supercedes a Dec. 23 CASA order requiring all affected aircraft to flush out their engines before flying.
The second order was made after the discovery of a new problem. Aircraft owners reported that, when uncontaminated avgas was put into planes that had been purged of the Mobil product, the deposits returned.
CASA said the contaminant can take various forms, but it is most noticeable as a black viscous deposit on copper and copper alloys. Aircraft owners say they have seen nothing like the "gunk" they are draining from tanks that were filled with apparently normal avgas. It reportedly comes out purple and rapidly turns black when exposed to sunlight. It has jammed fuel pumps with a sludge that has attacked the brass and dissolved the rubber in various components.
The aviation industry will have to wait for an approved test to determine which of the grounded aircraft have escaped contamination. At presstime, it was still unclear how the contamination had occurred in the first place.
Avgas supply
Avgas is made by selecting the high-octane output from isomerization, alkylation, and catalytic reforming units. The components are blended with additives to suppress gum formation and engine deposits. The vapor pressure is then adjusted by the addition of butane. Faults in any of these operations can produce off-spec product.
Low demand for the product-it comprises only 0.2% of refinery output in Australia-plus the requirement for high-octane components make it a special product. Mobil has become the main avgas supplier in Australia's southeastern states. Shell's Geelong refinery supplies a minor amount. Together, they account for about half of national demand. The remainder is supplied from BP's Kwinana refinery or from imports from Singapore.
The crisis comes as speculation grows that Mobil will be the prime casualty of the downstream oil refining industry's looming rationalization in Australia (OGJ, Jan. 3, 2000, p. 27). Already, the company has halved its production from the Port Stanvac refinery in Adelaide.
There is also a changeover in leadership. Mobil Oil Australia's chief executive, P.C. Tan, left Australia at the end of last year to take up a new position at ExxonMobil's global headquarters in Irving, Tex. His replacement is the former chief executive of Esso Australia Pty. Ltd., Robert Olsen, who presided over the Esso crisis surrounding the Longford gas plant fire and explosion in 1998.