By ANDY PASZTORU.S. aviation regulators on Monday are slated to propose enhanced inspections and fixes of anti-icing systems and stall-warning devices on hundreds Bombardier regional jets.
The FAA moves follow safety recommendations by the manufacturer and subsequent directives issued by Canadian regulators. They affect more than 960 airliners and include most Bombardier jet models manufactured since the early 1990s.
On about one-third of the jets, the FAA is seeking to prevent malfunctions of devices that help warn pilots of an impending aerodynamic stall. On the rest of the planes, the FAA is proposing stepped-up maintenance of heating elements intended to prevent ice buildup on the wings.
Improper operation of these safety systems, especially if pilots aren't aware of breakdowns, can be particularly dangerous in icing conditions when aircraft typically stall at a higher speed than normal. The FAA said the result in both cases could be "reduced controllability of the aircraft," though there haven't been any reports of accidents.
For more than 360 of the larger twinjet CRJ 700-series models built by Canada's Bombardier Inc. and flown by U.S. carriers, the Federal Aviation Administration proposes to inspect, and in some cases replace, various parts that measure the upward angle of wings during flight. According to the agency, defective parts can result in early or late activation of stall-warning and stall-prevention devices in cockpits that alert pilots when planes are in danger of losing lift. The airworthiness directives go beyond previous U.S., Canadian and European safety directives covering the same parts.
Bombardier's regional jets are used around the world, including fleets that fly commuter routes for Delta Air Lines Inc., AMR Corp.'s American Airlines and UAL Corp.'s United Airlines.
Previously, regulators from all three jurisdictions issued similar mandates covering the same parts used on certain Bombardier Q400 turboprops. And in February, European regulators mandated inspections and replacement of the same type of parts provided by the same supplier but installed on wide-body Airbus jets. All the affected parts are supplied by a unit of France's Thales SA, according to Bombardier officials.
For about 600 older versions of Bombardier jets used by U.S. carriers, the FAA is proposing new safeguards to ensure proper operation of systems that use hot air to keep ice from accumulating on the front edges of wings. FAA officials and their Canadian counterparts have identified several in-service incidents when the system failed to work properly and didn't alert pilots about potentially dangerous ice buildup on a portion of the wings. The FAA is proposing stepped-up inspections, along with modification or replacement of portions of these systems
A Bombadier spokeswoman said that Thales supplies so-called angle-of-attack vanes for both its Q400s and the CRJ family of aircraft. She said most of the planes operating in North America have been inspected in advance of regulatory deadlines, and Thales has provided parts to speed up the process.
The spokeswoman added that "safety is Bombardier's top priority" and the plane-maker responded with its own safety alerts "well in advance" of moves by regulators
Over roughly the last two decades, Bombardier jets have suffered at least eight accidents or serious incidents stemming from loss of lift caused by ice buildup on their wings, according to aviation safety experts. Some versions of the jets are particularly vulnerable to such icing because they lack slats — movable panels at the front of the wings that increase lift during takeoffs, landings and maneuvers at slow speeds.
Bombardier has said that starting last year it acted proactively to investigate icing-related defects with angle-of-attack sensors as soon as it learned about similar problems on Airbus jets.
Write to Andy Pasztor at firstname.lastname@example.org