Monday, December 22, 2008
Safety Watch – CRJ Gear Failures, Icing
NTSB Investigates CRJ Gear Failures
The National Transportation Safety Board launched an investigation into the twin gear failures aboard a US Airways Air Wisconsin CRJ 200 in Philadelphia and a Mesa Airlines United Express CRJ 700 at Chicago. The CRJ problems follow the 2007 landing gear problems on Bombardier’s Q400s, which grounded the worldwide fleet. Related Story
Bombardier noted the rarity of such events related to its CRJ aircraft. It also said the landing gear problems with the Q400 and those of the of the CRJ 200 as the design and manufacturer (Messier-Dowty) of the CRJ200 aircraft landing gear is completely different. “Though the cause of the incident is still unknown, we have been in touch with US Airways Express and Air Wisconsin Airlines,” said Spokesperson John Arnone. “We are also offering our assistance to the local authorities in their investigation and have dispatched a team to Philadelphia to support the airline in its review of the incident.”
as for the Mesa aircraft, Arnone said this was the first incident of its kind on the CRJ700 aircraft since the first aircraft entered revenue service in February 2001. “The CRJ700 aircraft landing gear design and manufacturer (Goodrich) is different from that of the CRJ200 aircraft and the design is different from that of the Q400 aircraft, which also uses Goodrich landing gears,” he said. “Our people have been in contact with United Express and operator Mesa Airlines.” It is also offering assistance to local auhorities in Chicago and has dispatched a team to support the airline and review the incident.
The failures happened within a day of each other and began with the Air Wisconsin flight making a gear-up landing last week when its left main landing gear failed to extend. After an hour’s worth of trouble shooting, the aircraft landed without its left main gear. The aircraft was on a ferry flight with only the pilots and flight attendant on board, having been delayed out of Norfolk and its passenger re-accommodated on other flights. The flight landed on a blanket of foam on Runway 27 Left shortly after 5 pm, closing the airport for about an hour. The CRJ 200’s left wing was lifted by crane, allowing the gear to be extended manually before it was towed off the runway where NTSB could begin its investigation.
The United Express aircraft suffered a gear-up landing, this time at O’Hare when a United Express flight from Chicago to South Bend was forced to return to Chicago after takeoff when the pilots received an “unsafe gear” warning in the cockpit. None of the 28 passengers on board was injured and were later accommodated on other flights.
NTSB Issues Icing Alert
Now that we are well into the icing season, the National Transportation Safety Board issued a Safety Alert titled "Activate Leading-Edge Deice Boots As Soon As Airplanes Enter Icing Conditions." This has been an ongoing issue with regional aircraft for over a decade. While not naming any specific aircraft, the board directed the alert to the pilot community, intending “to increase the visibility of airplane icing issues and address procedures taught regarding the accumulation of ice before activating deice boots," said NTSB Acting Chair Mark V. Rosenker.
Some of the highlights of the newly issued Safety Alert, approved by all five Board Members, remind pilots that:
• as little as 1/4 inch of ice can be deadly
• as little as 1/4 inch of leading edge ice can increase stall speed 25 to 40 knots; and
• early activation of the deice boots limits the effects of leading-edge ice and improves the operating safety margin.
The Safety Alert states that leading-edge deice boots should be activated as soon as icing is encountered, unless the aircraft flight manual or the pilot's operating handbook specifically directs not to activate them. In the Alert, pilots are instructed to maintain extremely careful vigilance of airspeed and any unusual handling qualities if the aircraft manual or the pilot's operating handbook allows for an accumulation of ice before activating the deice boots, and to turn off or limit the use of the autopilot in order to better "feel" changes in the handling qualities of the airplane.
"When followed, this Safety Alert will create a safer environment for pilots flying in icing conditions," Rosenker stated.