The Federal Aviation Administration (FAA) is proposing a significant expansion of its icing certification standards, including a new requirement that manufacturers show airplanes can operate safely in freezing drizzle or freezing rain, conditions that constitute an icing environment known as “supercooled large drops” (SLDs).
The proposed regulations would improve safety by mandating that new transport category aircraft most affected by SLD icing conditions meet expanded safety standards, including additional airplane performance and handling qualities. The rule also would require all new transport category designs be able to fly in conditions where supercooled liquid and ice crystals exist.
The FAA is also proposing changes that would expand the icing certification requirements for engines, engine installations and some airplane components (for example, angle of attack and airspeed indicating systems). These systems would need to be able to perform in freezing rain, freezing drizzle, ice crystals and combinations of these icing phenomena.
“These new icing standards are part of our continuing effort to make the world’s safest aviation system even safer,” said U.S. Transportation Secretary Ray LaHood.
“These regulations will help ensure future aircraft can operate safely in some of the toughest icing conditions,” said FAA Administrator Randy Babbitt.
The proposed rule is based largely on recommendations from the FAA’s Aviation Rulemaking Advisory Committee (ARAC) and the National Transportation Safety Board (NTSB). The FAA tasked the ARAC to study how icing certification regulations should be expanded after the tragic 1994 icing-related accident in Roselawn, IL. The NTSB recommendations stemmed from the same accident.
Previously, the FAA issued 112 airworthiness directives for transport category aircraft related to icing. Of the 112 ADs, 21 were specifically related to SLD. The ADs require flight crews to exit icing conditions when they see visual cues indicating the conditions exceed the capabilities of the aircraft’s ice protection equipment.
The Notice of Proposed Rulemaking can be found at: edocket.access.gpo.gov/2010/2010-15726.htm