Tuesday, April 15, 2014

Regulators order inspection of Bombardier airplanes: Pedal parts ‘may be prone to premature fatigue cracking,’ Transport Canada says

MONTREAL — Canadian and U.S. aviation regulators have ordered Bombardier Inc. to inspect pilots’ rudder pedals for fractures on three more regional-jet models sold to airlines around the world.

The airworthiness directive (AD) — repair or inspection orders regulators issue to aircraft manufacturers — from Transport Canada and the U.S. Federal Aviation Administration (FAA) concern Bombardier’s CRJ700 70-seat, CRJ900 90-seat and CRJ1000 100-seat series of regional jets. The AD issued by Transport Canada Civil Aviation (TCCA) on Jan. 8 extends its previous order last May to inspect pilot-side rudder pedal tubes for cracks and fractures on Bombardier’s smallest — and oldest — regional aircraft, the 50-seat CRJ200.

An “unsafe condition” is caused by “premature fatigue cracking” and could result in loss of control of the aircraft, both regulators said.

The directives were issued after two reports found cracks in the rudder pedal parts of a 50-seat jet. But the part is the same one installed in the larger jets and “may (also) be prone to premature fatigue cracking,” TCCA noted.

Marc Duchesne, spokesman for Bombardier Aerospace, said the company sent out a service bulletin to carriers on Nov. 15, but that type of inspection suggestion is not mandatory to follow. Even with the new inspection order, the issue does not “pose a danger currently,” he said.

Duchesne couldn’t say which airlines the two aircraft in question belonged to, at which airports the cracks were found, nor when they occurred.

Hans Weber, an aircraft safety expert and founder of San Diego-based TECOP International Inc., said that “in a case like this, I would expect they would replace the parts. And not only replace the parts, but because there’s obviously something wrong with them, redesign them also — strengthened.”

But Duchesne said the tube that connects to the rudder pedal is made by Bombardier in-house, and will be neither redesigned nor strengthened.

“Basically, that’s because with this directive, now every 26,000 cycles (takeoffs and landings) there’s a check. So if they need to replace the part, well, they put another one in and check it again after the next 26,000 cycles.”

FAA spokesman Les Dorr said the U.S. regulator was complying with its Canadian counterpart’s order, as is the agreement between the two organizations.

“We are mirroring whatever is in the Transport Canada AD.”

He said about 400 of the three aircraft series targeted by the latest directive are flown by U.S. carriers.

Bombardier has sold more than 1,700 regional jets to operators worldwide in the last 20 years.

Transport Canada spokeswoman Karine Martel said officials were not available for comment this week.

Weber said that “since the FAA issued a directive, it’s a serious matter. An AD is issued only if it’s a flight-critical matter.”

Rudder pedals are used mostly during takeoffs and landings, often to compensate for crosswinds.

“Losing a rudder would mean that you couldn’t compensate for that,” said Weber.

“The other thing of concern theoretically would be that the rudder somehow could get into an uncommanded deflection. That would really be destructive. That is, if the airplane is flying at regular speed and the rudder goes in one direction at full extent because something in the controls broke. That could just break off the tail.”

The most dangerous situation would be during landing, since any issue with the rudder would likely be detected before a takeoff roll, when pilots test the systems.

The issue is only on the pilot-side rudder pedals because it results from putting on the parking brakes, the regulators said.

John Maris, a former test pilot with the Canadian Armed Forces, said that “it’s always the pilot who sets the parking brake (as opposed to the first officer). And you push quite hard. And it turns out that they are finding these things are fatiguing and cracking early.”

Maris cautioned that such directives “are not issued lightly, but they don’t have to be catastrophic. It’s just a mechanism to make sure that someone doesn’t coast with a problem that gets worse with time. It’s not a crisis crisis. ”

But Weber noted that a directive adds urgency and “is the result of an escalation.” It usually follows a manufacturer’s service bulletin and then a regulator’s advisory circular, neither of which is mandatory to follow.

Maris said that “you catch a crack before it gets to a critical radius or length where it suddenly fails completely and suddenly. This is a normal precaution.

“I don’t see any risk to the public if the directive is complied with.”

Source:   http://www.montrealgazette.com