NTSB: Rolls needs to redesign Trent 800 component to prevent icing
Friday March 13, 2009
The US National Transportation Safety Board late Wednesday issued an "urgent safety recommendation" calling for Rolls-Royce to "redesign" the Trent 800's fuel/oil heat exchanger to prevent the fuel feed system icing that is believed to have caused both the uncommanded loss of thrust on a Delta Air Lines 777-200ER last November and the dual rollback that led to the January 2008 British Airways -200ER crash landing at London Heathrow.
The UK's Air Accidents Investigation Board yesterday issued a second interim report on the LHR crash that details extensive testing conducted by Boeing demonstrating that the accident likely was caused by FOHE ice buildup that restricted fuel flow. "With two of these rollback events occurring within a year, we believe that there is a high probability of something similar happening again," NTSB Acting Chairman Mark Rosenker said.
US FAA recently issued an amended airworthiness directive pertaining to Trent 800-powered 777s to incorporate new procedures recommended by Boeing to reduce the risk of fuel feed system icing.
But NTSB stated, "While the procedures may reduce the risk of a rollback in one or both engines due to FOHE ice blockage, they add complexity to flight crew operations, and the level of risk reduction is not well established. And because the recovery procedure requires a descent, the aircraft may be exposed to other risks." The board added that "the only acceptable solution to this safety vulnerability is a redesigned FOHE that would eliminate the potential of ice buildup."
While Rolls has not commented publicly on a redesign, NTSB said that the engine manufacturer "indicated [on Feb. 23] that a redesign of the FOHE was underway, and that they anticipated the redesign to be tested, certified and ready for installation within 12 months." Rolls said in a statement issued to media that the AAIB interim report on the LHR incident "clearly states that the Rolls-Royce equipment on this flight met or exceeded all requirements. The report also highlights the emerging issue of ice buildup in commercial 'long-cold-high' routes. This is an industrywide issue which requires detailed research that is likely to shape future regulations and requirements."
by Aaron Karp
ATWONLINE
Friday March 13, 2009
The US National Transportation Safety Board late Wednesday issued an "urgent safety recommendation" calling for Rolls-Royce to "redesign" the Trent 800's fuel/oil heat exchanger to prevent the fuel feed system icing that is believed to have caused both the uncommanded loss of thrust on a Delta Air Lines 777-200ER last November and the dual rollback that led to the January 2008 British Airways -200ER crash landing at London Heathrow.
The UK's Air Accidents Investigation Board yesterday issued a second interim report on the LHR crash that details extensive testing conducted by Boeing demonstrating that the accident likely was caused by FOHE ice buildup that restricted fuel flow. "With two of these rollback events occurring within a year, we believe that there is a high probability of something similar happening again," NTSB Acting Chairman Mark Rosenker said.
US FAA recently issued an amended airworthiness directive pertaining to Trent 800-powered 777s to incorporate new procedures recommended by Boeing to reduce the risk of fuel feed system icing.
But NTSB stated, "While the procedures may reduce the risk of a rollback in one or both engines due to FOHE ice blockage, they add complexity to flight crew operations, and the level of risk reduction is not well established. And because the recovery procedure requires a descent, the aircraft may be exposed to other risks." The board added that "the only acceptable solution to this safety vulnerability is a redesigned FOHE that would eliminate the potential of ice buildup."
While Rolls has not commented publicly on a redesign, NTSB said that the engine manufacturer "indicated [on Feb. 23] that a redesign of the FOHE was underway, and that they anticipated the redesign to be tested, certified and ready for installation within 12 months." Rolls said in a statement issued to media that the AAIB interim report on the LHR incident "clearly states that the Rolls-Royce equipment on this flight met or exceeded all requirements. The report also highlights the emerging issue of ice buildup in commercial 'long-cold-high' routes. This is an industrywide issue which requires detailed research that is likely to shape future regulations and requirements."
by Aaron Karp
ATWONLINE
