Dassault feeling the heat
Responding to Dassault’s claim that an “unanticipated request by the FAA” had prompted a redesign of the Falcon 7X bleed-air system (see page 58), the FAA insists there is no new regulation on this issue. “We have no new transport policy or rulemaking (including proposed rulemaking),” an FAA spokesman told AIN. However, the 200 degrees C limit has been standard industry practice for decades. For example, Advisory Circular 25-8 states, “There is a general industry/FAA practice that a temperature providing a safe margin […] results in a maximum surface temperature of approximately 400 degrees F [204 degrees C] for an affected component.” Another AC relaxes this limit to 232 degrees C, provided certain conditions (ambient pressure, dwell time, fuel type and so on) are met. Dassault responded that the 200-degrees-C standard does exist but is not mandatory. “We are anticipating a rule that should be enforced in a few months,” executives said. Current Falcons use 330-degrees-C systems, and the Falcon 7X had originally been designed the same way. The bleed-air system redesign resulted in a more complex, heavier system.