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DI<;PARTMF:NT OF TRANSI'ORTATION

Fl"dcrlll Avi:ltiOIl Administration

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IDnl'1wt No. 1'1\1\-2010-0375; IJircctorafc Identifier 2010-Nf\:I~nJ4-AJ); Anu'lldmcnt f\NI~-171

IUN 2120-AA64

Ainvorthinl'ss Oi"cctivcs; Bombardier, 1m:. Model CL-600-2B 19 (Regional Jet Series

J 00 & 440) Airplane::;; Model CL-600-2C I0 (Regional .Jet Serie5 700, 70 I, & 702)

Airplanl'-s~ Model CL-600-2D15 (Regional Jet Series 705) and Model CL-600-2D24

(Regional Jet Series 900) Airplanes

AGENCY: Federal Aviation Administration (FAA), Department ofTranspoltatioll

(DOT)"

ACTrON: Final rule.

SUf\:IMi\I{Y: We arc adopting a llCW airworthiness directive (AD) lbr lhe products listed

abnve, This AD results from mandatory contillllilt airworthiness inrormation (r'vlCAI)

"" d I "" I" f / I "ct "/" / "" onglllatc )y ,Ill avmttOIl aul" lOnty 0 ' anot leI' country to I cnt! y tHl{ eoneet un llnsuh~

condition on an aviation prouu(,;1. The MeAl dcJribes the unsafe (';llndilion as:

Following live reported cases of balance JaSher screw luilurc on similar

ADCh; lair-driven gellcralorsJ!ram air turbines instalkd on othcr ain.:rali

types, investigation by I-Iam-ilton Sundstrand ddemlined Ihal a specific

baldl of the screws had a lm:iallographic non-conformilY that increased

their susc<.:ptibility to brittle fracture. '" .•..•.

Failure of LI balance washcr serew can rcsuh in loss of the relaled balance

washer, with consequent turbine imbalance. Such imbalance ..:.ould

potentially result in ADO slructural failure (including blade lllilurc), loss

of ADG ch:ctric<ll power and structural dal1l<lgc to the aircr,,1i ,md. if

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

IDocket.;No. FAA-2010-0375; Directorate Identifier 2010-NM-014-AD; Amendme

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Ainvorthiness Directivesj Bombardier, Inc. Model CL-600-2B19 (Regional Jet Serie

100 & 440) Airplanes; Model CL-600-2CIO Cfegional Jet Series 700, 701, & 702)

Airplanes; Model CL-600-2DI5 (Regional Jet Series 705) and Model CL-600-2D24

(Regional Jet Series 900) Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of,Transportation

(DOT).

ACTION: Final rule.

SUMMARY: We are adopting a new airworthiness directive (AD) for the products lis

above. This AD results from mandatory cODtinLng aiIVIorthiness information (MeAD

originated by an aviation authority of another Luntry to identify and correct an unsafe

condition on an aviation product. The MeAl describes the unsafe condition as:

Following five reported cases of balance washer screw failure on similar

ADGs [air~driven generators]/ram air ~rbines installed on other aircraft

types, investigation by Hamilton Sundstrand determined that a specific

batch of the screws had a metallographic non-conformity that increased

their susceptibility to brittle fracture. * * *

Failure of a balance washer screw can result in loss of the related balance

washer, with consequent turbine imbalance. Such imbalance could

potentially result in ADG structural failhre (including blade failure), loss

of ADO electrical power and structural :damage to the aircraft and, if

FAA Form 1360-14.1 (6-89) OFFICIAL FILE COPY