# 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 CA R Standard 625, A ppendix H , the conti n ui ng ai r w or thi ness of a C a nadi 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 a ti on of the ai r c r a f t. Al ter n ati 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 e nced 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 s i 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 e phone 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 Communica tions Centre (A A RC)

at Place de Ville, Ot t a w a , Ont a rio K 1 A 0N 8 , 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) 

# 1/1 No



## . 

# CF-2005-28R1

Issue Date


# 14 June 2007

Num b er: CF-2005-28R1

Subject: Pow e r Turbine RPM Steady State Operation Av oidance

Effectiv e: 14 June 2007

Rev i sion: Supersedes Airworthiness Dire ctive CF-2005-28, August 2005.

Applicability : Bell Helicopter Textron Canada (BHTC) Model 206L-3 serial numbers 51001 through 51612, and 206L-4 helicopters serial numbers 52001 through 52313.

Helicopters fitted with two 250-C20R engines as per Supplementary Type Certificate (STC) SR00036SE are excluded.

Compliance: As indicated.

Background: Transport Canada has been advised of multiple reports of failure of the third stage turbine wheel used in both the Rolls-Royce 250-C30S and 250-C47B engines. There have been eight in-flight failures reported. Rolls-Royce has determi ned that detrimental vibrations can occur within a particular r ange of turbine speed as a potential contributing

factor to these failures. BHTC revised t heir rotorcraft flight manual and provided a decal to inform pilots to avoid steady stat e operations at these engine turbine speeds.

This revision is issued to exclude helicopter s having the 250-C20R engines installed per STC SR00036SE (twin engine conversion)

Correctiv e

Actions: Part A: Rotorcraft Flight Manual Amendment

Within 10 calendar days after the effective date of this directive, insert into the appropriate flight manual revision BHT-206L3-FM-1, Revision 6, dated 26 April 2005, BHT-206L4-FM--1, Revision 6, dated 26 April 2005, or later revisions approved by Chief, Continuing Airworthiness, Transport Canada in to the rotorcraft flight manual and advise the pilot of this change.

Part B: Installation of Decal

In conjunction with Part A above, install the decal as per Alert Service Bulletin
206L-05-134, dated 8 June 2005, or later re visions approved by Chief, Continuing Airworthiness, Transport Canada.

Authorization: For Minister of Transport, In frastructure and Communities

Bohdan Goyaniuk
Chief, Continuing Airworthiness

Contact: Mr. Bogdan Gajewski, Continuing Airworthiness, Ottawa, telephone 613 952-4450,

f a csimile 613 996-9178 or e-mail gajewsb@tc.gc.c a or any Transport Canada Centre.