Graham Warwick/ATLANTA

A FIRE-RESISTANT hydraulic fluid able to operate for longer at higher temperatures will be available early in 1997. US petrochemical group Monsanto says that it is now commercialising its Skydrol 5 fluid after successful in-service tests.

McDonnell Douglas (MDC) has already approved the fluid for use in its airliners after an 18-month flight evaluation in a Swissair MD-11. The Douglas Aircraft division, says that Skydrol 5 is able to work at an operating temperature of 135¡C, compared with 107¡C for current Type IV fluids.

Testing has shown that, at 135¡C, the useful life of Skydrol 5 is "-significantly extended, compared to Type IV fluids", says Ron Gerson, international manager for aviation products at Monsanto.

"Also, in testing, Skydrol 5 displayed outstanding erosion protection and pump reliability at these extreme temperatures, unlike existing Type IV fluids," he says. Skydrol 5 is lighter than current phosphate-ester-based hydraulic fluids, Monsanto says. The weight reduction would save about 6,400litres of fuel a year in an MD-11 or Airbus A300, rising to about 9,100litres in a Boeing 747-400, the company estimates.

"Because Skydrol 5 is compatible with all existing Type IV fluids, converting-will be as simple as topping-off existing hydraulic systems. No flushing or draining is necessary," Gerson says.

Source: Flight International