# Transport Transports

Canada Canada T P 7245E



# AIRWORTHINESS DIRECTIVE

T he f o l l o w i ng ai r w or thi ness di r e cti v e ( A D ) may be appl i c abl e to an ai r c r a f t w h i c h our r e cor d s i ndi cate i s r e g i ster ed i n y our na me. AD s ar e i ssued pur suant to Canadian Aviation Regulation (CA R ) 5 9 3 . Pur s uant to C A R 605.84 and the f u r t her detai l s of C A R St andard 625, A ppendix H , the conti nui ng ai r w or thi ness of a C anadi an r e g i ster ed ai r c r a f t i s conti n g ent upon compl i ance w i th al l appl i c abl e AD s. Fai l u r e to compl y w i th the r e q u i r ements of an AD may i n v a l i dat e the f l i g ht author i z ati on of the ai r c r a f t. Al ter nati v e means of compl i ance shal l be appl i ed f o r i n accor dance w i th C A R 605.84 and the abov e- r e f e r enced Standard

. T h i s AD has been i ssued by the C onti nui ng Ai r w or thi ness D i v i si on ( AAR D G )

, Ai r c r a f t C e r t i f i c ati on Br anch, T r anspor t C anada, Otta w a , tel ephone 613 952- 4357.

Pur s uant to C A R 202.51 the r e g i ster ed ow ner of a C anadi an ai r c r a f t shal l

, w i thi n sev en day s, noti f y the M i ni ster i n w r i t i n g of any chang e of hi s or her name or addr ess.

T o r e q uest a chang e of addr ess, contact the Civ il A v iat i on Communicat ions Centre (A A RC)

at Place de Ville, Ot t a w a , Ont a rio K1A 0N8 , or 1- 800- 305- 2059

, or www. t c

. g c

. c a / c i v i l a v i a t i o n / c o m m u n i c a t i o n s / c e n t r e / a d d r ess.asp

24- 0022 ( 01- 2005) 

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# CF-1990-06R1

Issue Date 

# 07 January 2008

Num b er: CF-1990-06R1

Subject: Tail Rotor Pitch Change Chain

Effectiv e: 24 January 2008

Rev i sion: Supersedes Airworthiness Directive CF-90-06.

Replacement: Supersedes FAA Airworthiness Directive 76-12-07 for Model 204B.

A pplicability : Bell Helicopter Textron Inc., (BHT) Model 204B helicopters equipped with tail rotor pitch change chain (silent chain) P/N 204-001-739-003, 204-001-739-105 and

205-001-721-001.

C o mpliance: As indicated unless already accomplished.

Background: There have been two accidents attributed to the in -flight failure of the tail rotor pitch change
chain. In both cases, cracks originated at the center of a lin k within the pitch change chain.

An in-situ check of the chain has shown not to be reliable in detecting cracking of the chain. This revision extends applicability to chains of newer part numbers.

Correctiv e Actions: Part A

At every 100-hour scheduled inspection:

1. Remove and clean the chain in accor dance with instructions provided in BHT-204B-M&O-1, Maintenance and Overhaul Instructions, Revision 3 dated 7 April 2006.

2. Inspect for cracks in the link segments us ing a 10-power or higher magnifying glass and a bright light. Particular attention should be placed to the links of t he chain that travel over the sprocket and six inches each side of this portion.

Remove from service chains with crack ed or broken links or segments before further flight. Install airworthy chains in acco rdance with the applicable maintenance manual; lubricate and rig the controls as spec ified in the applicable maintenance manual.

Part B

At every 25 hours, not coinciding with Part A inspections:

1. Remove the cover from the chain assembly.

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N ° 

# CF-1990-06R1 2/2

2. Inspect for cracks in the link segments us ing a 10-power or higher magnifying glass and a bright light. Particular attention should be placed to the links of t he chain that travel over the sprocket and six inches each side of this portion.

Remove from service chains with crack ed or broken links or segments before further flight. Install airworthy chains in acco rdance with the applicable maintenance manual; lubricate and rig the controls as spec ified in the applicable maintenance manual.

Authorization: For Minister of Transport, In frastructure and Communities

P. Tang Acting Chief, Continuing Airworthiness

Contact: Mr. Bogdan Gajewski, Continuing Airworthi ness, Ottawa, telephone 613-952-4450, facsimile 613-996-9178 or e-mail: gajewsb@tc.gc.c a or any Transport Canada Centre.