.+. Transport

Canada

Transports

Canada No.

CF-2010-01

Issue Date

TP 7245E

I 1/2

AIRWORTHINESS

18 January 2010

DIRECTIVE

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''''l''1Creo .;rer.n,. CO"tln~enlupon compl,ance WIll>all applk"hle ADs. _allute tu.com~y wllh the requlremenlS 01an fg may invoiidsle the nlg~1authorizatlM or tile alfCfaft.

Allerna\iv<l means of compf",,,,,. shall o. applied To, In .o;;o,dar>ee with CAR 6OS.ManUthe .bo",,·,el.renc.ed Standard.

ThiSAD has b.sn iSSUBObythil Continuing Ai"",oMin.,. Di';.;on (AAROG),NsU""al Aircra!t certification Sra""h. Tran'portCanad., Oll.wa, le~p~nee1:' 952-4357.

Number:

Subject:

Effective:

Applicability:

Compliance:

Background:

Corrective

Actions:

CF·2010·01

Ram Air Turbine (RAT) - NonwConforming Balance Washer Screws

16 February 2010

Bombardier Inc. Models BD-700-1A10 and BD-700-1A11. Serial Numbers (SINs) 9002

and subsequent.

As indicated below,

Following five reported cases of balance washer screw failure on similar RATs/air driven

generators installed on other aircraft types, an investigation by Hamilton Sundstrand

determined that a specific batch of the screws had a metallographic non-conformity that

increased their susceptibility to brittle fracture. Subsequently, it was established that 187

RATs [Part Number (PIN) GL456-1101-7 and Hamilton Sundstrand PINs in the 762826

series) had non-conforming screws installed either during production or possibly during

maintenance or repair at Hamilton Sundstrand repair stations.

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 RAT structural

failure (induding blade failure), loss of RAT electrical power and structural damage to the

aircraft and, if deployment was activated by a dual engine shutdown, could also result in

loss of hydraulic power for the flight controls.

This directive mandates checking of the RAT and replacing the balance washer screws, if

required, It also prohibits future insta!lation of unmodified RATs.

Part I: Identification Check

Appiicable to BD-700-1A 10 and BD-700-1A11 aircraft, SINs 9002 through 9380.

Prior to the next scheduled in-flight operational test of the RAT after the effective date of

this directive, unless already accomplished, check the SIN of the installed RAT. This

check may be conducted visually. which requires the RAT to be lowered, or by checking

the delivery and maintenance records.

A If the RAT SIN is not listed in paragraph 1A of the applicable Bombardier Aerospace

Service Bulletin (SB) detailed below, or later revision approved by the Chief,

Continuing Airworthiness, Transport Canada, no further action is required, other than

compliance with Part III of this directive.

B, If the RAT SIN is listed in paragraph 1.A. of the applicable Bombardier Aerospace SB

detailed below, or later revision approved by the Chief, Continuing Airworthiness,

Transport Canada. inspect the RAT identification plate.

PUrJ;uant to CAR lOl.51 me. registored owner or • Canadian al",,-.-" .hall, wllhln "",on dayS, nOlily the Mini,to'

in wr1~ng 01 any chanll" of hiS or hor nama or address

To r~qua£l. cha~r address, contaClltte CI,II Aviation CommuniCaUons Cent", (AARCI

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No, CF-2010-01

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1) If symbol "24-7" is marked on the RAT identification plate. the balance washer

screws have already been replaced. No further action is required, other than

compliance with Part III of this directiv8_

2) If symbol "24-7" is not marked on the RAT identification plate, replacement of the

balance washer screws is required_ Proceed to Part II of this directive.

Part II: Replacement of the Balance Washer Screws and Identification of the RAT

Applicable to BD-700-1A 10 and BD-700-1A11 aircraft, SINs 9002 through 9380.

Prior to the next scheduled in-flight operational test of the RAT after the effective date of

this directive, unless already accomplished:

Replace all of the balance washer screws, and mark the RAT identification plate with

symbol "24-7", in accordance with the Accomplishment Instructions in the applicable

Bombardier Aerospace S8 detailed below, or later revision approved by the Chief,

Continuing Airworthiness, Transport Canada.

Note: Part II is only applicable if required by Part I, Paragraph B.2. of this directive.

Part III: Replacement Parts

Applicable to BD-700-1A 10 and BD-700-1A11 aircraft, SINs 9002 and subsequent

After the effective date of this directive:

It is not permitted to install a replacemenUspare RAT [PIN GL456-1101-7; Hamilton

Sundstrand PINs in the 762826 series] with one of the SINs listed in paragraph 1.A of the

applicable Bombardier Aerospace S8 detalled below, or later revision approved by the

Chief, Continuing Airworthiness, Transport Canada, unless it is identified with the symbol

"24-7" on the identification plate.

Authorization: For Minister of Transport, Infrastructure and Communities

ORIGINAL SIGNED BY

Derek Ferguson,

Chief, Continuing Airworthiness

Contact: Mr. Richard Topham, Continuing Airworthiness, Ottawa, telephone 613-952-4357,

facsimile 613-996-9178 or e-mail CAW Web Feedback@tc.gc.ca or any Transport

Canada Centre.