DEPARTMENT OF TRANSPORTATION (4910-l3-_P] 

# I Federal Aviation Administration 14CFR Part 39 

# D550 (Docket No. FAA-2010-*****; Directorate Identifier 2009-NM-124-AD] RIN 2120-AA64

100 &440) Airplanes; Model CL-600-2CIO (Regional Jet Series 700, 701, &702) Airplanes; Model CL-600-2DI5 (Regional Jet Series 705) AiIplanes; and Model CL-600-2D24 (Regional Jet Series 900) Airplanes AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice ofproposed rulemaking (NPRM). SUMlVlARY: We propose to adopt anew airworthiness directive (AD) forthe product, 

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>ATE Two cases ofacrack on a "dry" ADG (aiLdriven generator] (Hamilton Sundstrand part number in the 761339 series), inthe aft area ofthe strut and generator housing assembly, have been reported on CL-600-2B19 aircraft. The same part is also installed on CL-600-2ClO, -2DlS and -2D24 aircraft. Investigation determined that the crack was in an area of the strut where the wall thickness ofthe casting was below specification, due to amanufacturing anomaly in aspecific batch ofADGs. Structural failure and departure ofthe ADG during deployment could possibly result In damage to the aircraft. structure. Ifdeployment was activated by adual engine shutdown, ADG structural failure would also result in loss of hydraulics forthe flight controls. condition as: and correct an unsafe condition on anaviation product. The MeAldescribes the unsafe information (MeAD originated by an aviation authority ofanother country to identify listed above. This proposed AD results from mandatory continuing airworthiness14910-I3-P) "()lffi"""."""_ ANE-I7I DEPARTMENT OF TRANSPORT AnON Federal Aviation Administration 14CFR Part 39 (Docket No. FAA-2010-*****j Directorate Identifier 2009-NM-.124-AD) RIN 2120-AA64 "'.".l1lllGsn ANE-171 Ainvorthiness Directives; Bombardier, Inc. Model CL-600-2B 19 (Regional Jet Series 100 &440) Airplanes; Model CL-600-2CIO (Regional Jet Series 700, 701 & 702) Airplanes; Model CL-600-2D15 (Regional Jet Series 705)Airplanes; and Model CL-600-2D24 (Regional JetSeries 900) Airplanes AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice ofproposed rulemaking (NPRM). SUMMARY: We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MeAl) originated byan aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as: Two cases of acrack alla "dry" ADG (HamiJton Sundstrand part number inthe 761339 series), in the aft area ofthe strut and generator housing assembly, have been reported on CL-600-2BI 9 aircraft. The same part is also installed on CL-600-2C IO. -2D 15 and -2D24 aircraft. Investigation determined that the crack was inan area ofthe strut where the wall thickness ofthe casting was below specification, due to a manufacturing anomaly in a specific batch ofADGs. Structural failure and departure of the ADG during deployment could possibly result in damage to the aircraft structure. Ifdeployment was activated by adual engine shutdown, ADG structural failure would also result in loss ofhydraulics for the flight controls. IWl"'N" WMOO'. ANE-170 ,~rn"'-"'SJG ASocias

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