XX 

TRANSLATION OF 

BOLLETTINO TECNICO N° 109-129 

The technical content of this document is approved 

under the authority of DOA nr EASA.21J.005. 

DATE February 16, 2009

REV. xxxxxxx 

Compliance with 

this bollettino is: 

 XX Page 1 of 7

SUBJECT: INCLUSION OF POWER TURBINE N2 LIMITATIONS. 

REASON: Prescribe operational limitations for the power turbine speed in 

accordance with information provided by engine TCH (ref. Rolls-Royce 

C.E.B A-1400 Rev. 3), until the affected components have been 

replaced. 

HELICOPTERS AFFECTED:

All the Agusta A109A, A109AII and A109C helicopters equipped with the 

Allison / Rolls-Royce 250-C20B and 250-C20R/1 engines, in which the 

third stage turbine wheel P/N 23065833 is installed. 

COMPLIANCE:

Within the next 25 (twenty-five) operating hours after the receipt of this 

Bollettino and however before and not later than May 31, 2009. 

DESCRIPTION:

This Bollettino has been issued by Agusta based on information provided 

by engine TCH on the C.E.B. A-1400 Rev. 3. 

REQUIRED MANPOWER:

An estimated 0,5 (half) manpower hours are required for compliance with 

this Bollettino. 

WARRANTY:

N.A. 
B.T. 109-129 

Page 2 of 7 

REQUIRED MATERIALS:

The following material is required for compliance with this Bollettino: 

P/N DENOMINATION Q.TY

(*) Decal 1 

NOTE: (*) The decal shall be locally manufactured using white lettering 

on black background. The text for the decal shall be in capital 

letters having height not less than 3,5 mm as shown in figure 

1. 

SPECIAL TOOLS: 

N.A. 

WEIGHT AND BALANCE CHANGES: 

N.A. 

REFERENCES:

Rolls-Royce C.E.B. A-1400 Rev. 3 (attached). 

PUBLICATIONS AFFECTED: 

A109A up to S/N 7165 Flight Manual. 

A109A S/N 7166 and subs. Flight Manual. 

A109AII Flight Manual. 

A109C Flight Manual. 

COMPLIANCE INSTRUCTIONS:

1. Determine the P/N of the installed third stage turbines wheels. 

2. If the third stage turbine wheel of one or both engines is P/N 

23065833 proceed in accordance with step 4 of this Bollettino. 

3. If the third stage turbine wheel of the two engines is not P/N 

23065833 no further actions are required, proceed in accordance 

with step 9 of this Bollettino. 

4. Prepare the helicopter on ground for a safe maintenance, 

disconnect any power supply. 

5. Install on the instruments panel, below or near the “ENGINE & 

ROTOR RPM POWER TURBINE (N2)” however in an area visible 

by the pilot, one of the two decals shown in figure 1 (in accordance 

with the instruments panel configuration) reporting the following 

text: “MIN. CONT. 97% N2 – MIN. TRANS. 95% N2”. 
B.T. 109-129 

Page 3 of 7 

NOTE

Avoid steady-state operation in the 95-97% 

N2 range for more than 60 seconds in single 

or cumulative events. 

Steady-state operation is defined as any 

manoeuvre during which an attempt is being 

made to maintain a constant engine speed 

within 2% N2 

6. A109A and A109AII helicopters

Insert in the applicable Flight Manual, Section I – OPERATING 

LIMITATIONS, paragraph “POWER PLANT LIMITATIONS” the 

page 5 or 6, as applicable, of this Bollettino. 

7. A109C helicopters

Insert in the Flight Manual, Section I - LIMITATIONS, paragraph 

“POWER PLANT AND TRANSMISSION LIMITATIONS” the page 

7 of this Bollettino. 

8. Return the helicopter in a ready to flight condition. 

9. Record compliance with this Bollettino in the helicopter log book. 
B.T. 109-129 

Page 4 of 7 

MIN. CONT. 97% N2 - MIN. TRANS. 95% N2 

OR 

MIN. 

CONT. 

97% 

N2 

MIN. 

TRANS. 

95% 

N2

Letter: white colour 

Background: black colour 

Letter height: 3,5 mm 

FIGURE 1
B.T. 109-129 

Page 5 of 7 

 

BT 109-129 

A109A Flight Manual

POWER PLANT AND TRANSMISSION LIMITATIONS 

ENGINES ALLISON / ROLLS ROYCE 250-C20B WITH 3RD-STAGE 

TURBINE WHEEL P/N 23065833 INSTALLED. 

POWER TURBINE (N2) RPM 

Minimum RPM 

 continuous : 97 % 

 transient: 95 % 

Avoid steady-state operation in the 95-97% N2 range for more than 60 

seconds in single or cumulative events. 

Steady-state operation is defined as any manoeuvre during which an 

attempt is being made to maintain a constant engine speed within 2% 

N2.
B.T. 109-129 

Page 6 of 7 

 

BT 109-129 

A109AII Flight Manual

POWER PLANT AND TRANSMISSION LIMITATIONS 

ENGINES ALLISON / ROLLS ROYCE 250-C20B OR 250-C20R/1 WITH 

3RD-STAGE TURBINE WHEEL P/N 23065833 INSTALLED. 

POWER TURBINE (N2) RPM 

Minimum RPM 

 continuous : 97 % 

 transient: 95 % 

Avoid steady-state operation in the 95-97% N2 range for more than 60 

seconds in single or cumulative events. 

Steady-state operation is defined as any manoeuvre during which an 

attempt is being made to maintain a constant engine speed within 2% 

N2.
B.T. 109-129 

Page 7 of 7 

 

BT 109-129 

A109C Flight Manual

POWER PLANT AND TRANSMISSION LIMITATIONS 

ENGINES ALLISON / ROLLS ROYCE 250-C20R/1 WITH 3RD-STAGE 

TURBINE WHEEL P/N 23065833 INSTALLED. 

POWER TURBINE (N2) RPM 

Minimum RPM 

 continuous : 97 % 

 transient: 95 % 

Avoid steady-state operation in the 95-97% N2 range for more than 60 

seconds in single or cumulative events. 

Steady-state operation is defined as any manoeuvre during which an 

attempt is being made to maintain a constant engine speed within 2% 

N2.

ALERT

Page 1 of 9

December 22, 2006

Revision 3

January 19, 2009

2008 RollsïRoyce Corporation

250ïC20 Series CEB Aï1400

250ïC20R Series CEB Aï72ï4095

250ïB17 Series TP CEB Aï1343

250ïB17F Series TP CEB Aï72ï2091

ENGINE, TURBINE ASSEMBLY ï STEADYïSTATE OPERATION

AVOIDANCE RANGE LIMIT

1. PLANNING INFORMATION

A. Effectivity

(1) Engines

All Rolls-Royce Model 250ïC20, ïC20R, ïB17 and ïB17F Series engines are affected by

this Commercial Engine Bulletin (CEB).

(2) Spares ï Not affected

B. Reason

This CEB is being revised to clarify and communicate the required engine N2 speed avoidance

range for all Model 250 Series II engines. The required engine N2 speed avoidance range is

dependent upon the part number of the 3rdïstage turbine wheel in service and the OEM

application in which the engine is installed. Of the three different designs of 3rdïstage turbine

wheel in service, this CEB specifically addresses the action by part number of the two affected

wheels and the OEM applications where relevant. Part numbers of the three 3rdïstage turbine

wheels in service and the OEM applications affected are as follows:

(1) Enhanced Power Turbine Fitted with P/N 23065818 3rdïstage Turbine Wheel.

Changes documented in the previous revisions of this CEB that address the Speed Limit

Tables for the enhanced P/N 23065818 3rdïstage turbine wheel remain in effect. This

speed avoidance range is applicable to all OEM applications.

(2) NonïEnhanced Power Turbine Fitted with P/N 23065833 3rdïstage Turbine Wheel.

For normal operation, the OEM applications affected are those with a cruise power rating of

350 SHP or above: Agusta A109 (all models), Soloy B206L/R and Eurocopter BO105 (all

models). In addition and for One Engine Inoperable (OEI) only, the following OEM

application is affected: Eurocopter AS355 (all models). P/N 23065833 wheel is no longer

manufactured and so alternative options for replacement of the wheel at next turbine

overhaul are discussed in paragraph 2.C.(1)(d).

(3) NonïEnhanced Power Turbine Fitted with P/N 23001967 3rdïstage Turbine Wheel.

No N2 speed avoidance range is required for any OEM application. P/N 23001967 wheel

is not affected by this CEB and is mentioned only for completeness.

This CEB provides advanced notification of actions pertaining to the 3rdïstage turbine wheel

that are being incorporated in all applicable Model 250 Series II engine Operation and

Maintenance Manuals.

C. Description

This CEB requires Operators to avoid engine N2 steadyïstate operation in the speed avoidance

range as specified by 3rdïstage turbine wheel part number in the following wording and charts.

Transition through the speed range is to be accomplished as expediently as possible.

D. Approval

Technical aspects are FAA approved.

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December 22, 2006

Revision 3

January 19, 2009

2008 RollsïRoyce Corporation

250ïC20 Series CEB Aï1400

250ïC20R Series CEB Aï72ï4095

250ïB17 Series TP CEB Aï1343

250ïB17F Series TP CEB Aï72ï2091

E. Compliance

Compliance Code 1: To be complied with immediately.

F. Interchangeability ï Not affected

G. Material Availability

PART NUMBER QTY/ENGINE NAME MODEL

23065833 1 Thirdïstage, Turbine Wheel C20 Series,

C20R Series

23065818 1 Thirdïstage, Turbine Wheel C20 Series,

C20R Series

23065818 1 Thirdïstage, Turbine Wheel B17 Series,

B17F Series,

C20S

H. Tooling ï Not affected

I. Weight and Balance ï Not affected

J. Electrical Load Data ï Not affected

K. References

(1) 10W2 Operation and Maintenance Manual, Turboshaft Models, 250ïC20, ïC20B, ïC20F,

ïC20J, ïC20S, ïC20W (OMM).

(2) 10W3 Overhaul Manual, Turboshaft Models 250ïC20, ïC20B, ïC20F, ïC20J, ïC20S,

ïC20W (O/H).

(3) 10W4 Illustrated Parts Catalog, Turboshaft Models 250ïC20, ïC20B, ïC20C, ïC20F,

ïC20J, ïC20S, ïC20W (IPC).

(4) 11W2 Operation and Maintenance Manual, Turboprop Models 250ïB17, ïB17B, ïB17C,

ïB17D, ïB17E (OMM).

(5) 11W3 Overhaul Manual, Turboprop Models 250ïB17, ïB17B, ïB17C, ïB17D,

ïB17E (O/H).

(6) 11W4 Illustrated Parts Catalog, Turboprop Models 250ïB17, ïB17B, ïB17C, ïB17D,

ïB17E (IPC).

(7) CSP21007 Operation and Maintenance Manual, Turboshaft Models 250ïC20R, ïC20R/1,

ïC20R/2, ïC20R/4 (OMM).

(8) GTP5232ï3 Overhaul Manual, Turboshaft Models 250ïC20R, ïC20R/1, ïC20R/2,

ïC20R/4 (O/H).

(9) CSP23007 Illustrated Parts Catalog, Turboshaft Models 250ïC20R, ïC20R/1, ïC20R/2,

ïC20R/4 (IPC).

(10) CSP21008 Operation and Maintenance Manual, Turboprop Models 250ïB17F, ïB17F/1,

ïB17F/2 (OMM).

(11) GTP5243ï3 Overhaul Manual, Turboprop Models 250ïB17F, ïB17F/1, ïB17F/2 (O/H).

(12) CSP23008 Illustrated Parts Catalog, Turboprop Models 250ïB17F, ïB17F/1,

ïB17F/2 (IPC).

L. Prerequisites ï None

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Revision 3

January 19, 2009

2008 RollsïRoyce Corporation

250ïC20 Series CEB Aï1400

250ïC20R Series CEB Aï72ï4095

250ïB17 Series TP CEB Aï1343

250ïB17F Series TP CEB Aï72ï2091

2. ACCOMPLISHMENT INSTRUCTIONS

A. Identification of Wheel and Action Required.

The part number of the 3rdïstage turbine wheel installed in a Model 250 Series II engine is

recorded in the engine logbook, Turbine Assembly (pink pages), Assembly Record, Part V. The

part number must be used to identify the appropriate action described in paragraph 2.B. or 2.C.

The following flowchart is included as a simple guide to help identify the appropriate action for

each wheel type.

NOTE: A temporary action only is required for the Agusta A109 (all models), Soloy B206L/R

and Eurocopter BO105 (all models) with the nonïenhanced 3rdïstage turbine wheel

P/N 23065833 installed, since this wheel will be permanently removed from service at

the next turbine overhaul (replacement options are discussed in paragraph 2.C.(1)(d)).

All other OEM applications with the nonïenhanced 3rdïstage turbine wheel P/N

23065833 installed do not require a temporary action.

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Revision 3

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2008 RollsïRoyce Corporation

250ïC20 Series CEB Aï1400

250ïC20R Series CEB Aï72ï4095

250ïB17 Series TP CEB Aï1343

250ïB17F Series TP CEB Aï72ï2091

B. Action A ï Enhanced Power Turbine Fitted with P/N 23065818 3rdïstage Turbine Wheel.

(1) This action is applicable to all Model 250 Series II Engines used in all OEM applications.

A mandatory 75% to 88% engine N2 steadyïstate speed avoidance range is required for

operation above 85 SHP (equivalent to 91.5 ftïlb (124.1 Nm) of torque). RollsïRoyce must

be consulted for additional guidance on the speed avoidance range for any OEM

application that has a potential steadyïstate operating speed below 89% N2.

Steadyïstate operation below 85 SHP or transient operation passing through this speed

range is allowable. This action applies to all flight and ground maintenance (including track

and balance) operational practices (Ref. FIG. 1, 2, 3 and 4).

(a) An entry into the engine logbook must be made for any steadyïstate operating

excursion into the 75% to 88% N2 speed avoidance range while operating above 85

SHP (equivalent to 91.5 ftïlb (124.1 Nm) of torque). If the total accumulated time

above 85 SHP exceeds 60 seconds for a single or multiple event, the turbine unit

must be removed from service and the 3rdïstage turbine wheel scrapped and

replaced with another P/N 23065818 wheel. If the cumulative time at steadyïstate

conditions above 85 SHP has possibly exceeded 60 seconds, or is unknown,

RollsïRoyce must be contacted for disposition of the wheel.

(b) Engines that have a logbook entry for a steadyïstate operating excursion into the 75%

to 88% N2 speed avoidance range or that have been used in an application that has

operated below 89% N2 should not be fitted on another OEM application without the

3rdïstage turbine wheel being scrapped and replaced.

NOTE: The 60 second operation restriction in the speed avoidance range between

75% and 88% N2 while operating above 85 SHP (equivalent to 91.5 ftïlb

(124.1 Nm) of torque) applies to sustained engine N2 steadyïstate

operation. It does not apply to transient operation passing through this

speed range. Steadyïstate operation is defined as any maneuver during

which an attempt is being made to maintain a constant engine speed within

2% N2.

C. Action B ï NonïEnhanced Power Turbine Fitted with P/N 23065833 3rdïstage Turbine Wheel.

(1) For normal engine operation, this action is required only for Model 250 Series II Engines

used in the following OEM applications: Agusta A109 (all models), Soloy B206L/R and

Eurocopter BO105 (all models). This action is required only until the next turbine overhaul

at which time the 3rdïstage turbine wheel must be removed from service. All other OEM

applications do not require this temporary action.

Two options are available to satisfy this action (paragraph 2.C.(1)(a) or 2.C.(1)(b)). Only

one option need be implemented:

(a) Conduct N2 Indication System Calibration Check.

A narrower N2 speed avoidance range is required if a calibration check on the N2

indication system can be performed to zero out any error. If this can be accomplished,

the required engine N2 speed avoidance range is 87% to 95% N2. If this cannot be

accomplished, refer to paragraph 2.C.(1)(b), for the required expanded engine N2

speed avoidance range that includes an appropriate allowance for the N2 indication

system accuracy of each OEM application affected.

(b) N2 Speed Avoidance Range.

The allowable engine N2 steadyïstate operating speed is a function of the engine N2

speed indication system error. The required engine N2 speed avoidance range is

documented in Table 1 for the affected OEM applications, and applies to both flight

and ground maintenance (including track and balance) operational practices.

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December 22, 2006

Revision 3

January 19, 2009

2008 RollsïRoyce Corporation

250ïC20 Series CEB Aï1400

250ïC20R Series CEB Aï72ï4095

250ïB17 Series TP CEB Aï1343

250ïB17F Series TP CEB Aï72ï2091

OEM Aircraft Speed Avoidance Range (% N2)

A109 85.0ï97.0

Soloy B206L 84.5ï97.5

BO105 86.5ï95.5

Table 1

OEM Application Specific Speed Avoid Range

An entry into the engine logbook must be made for any steadyïstate engine operation in

the N2 speed avoidance range regardless of engine power. The total time spent at

steadyïstate conditions in the N2 speed avoidance range during the event must be

recorded in the engine logbook. Once the total accumulated time of steadyïstate operation

exceeds 60 seconds, the turbine unit must be removed from service and the 3rdïstage

turbine wheel P/N 23065833 scrapped. If the cumulative time at steadyïstate conditions

above 85 SHP has possibly exceeded 60 seconds, or is unknown, RollsïRoyce must be

contacted for disposition of the wheel.

NOTE: The 60 second operation restriction in the speed avoidance range applies to

sustained engine N2 steadyïstate engine operation. It does not apply to

transient operation passing through this speed range. Steadyïstate

operation is defined as any maneuver during which an attempt is being

made to maintain a constant engine speed within 2% N2.

(c) N2 Gage Indication System Calibration or N2 Speed Avoidance Range Not Implemented.

If the N2 Gage Indication System or the N2 Speed Avoidance Range cannot be

implemented for any reason, the 3rdïstage turbine wheel P/N 23065833 must be removed

from service and a replacement wheel as discussed in paragraph 2.C.(1)(d) installed.

(d) Replacement Wheel Options at Turbine Overhaul.

At the next scheduled turbine overhaul, 3rdïstage turbine wheel P/N 23065833 must

be removed from service and scrapped. Replacement options are a direct swap with

P/N 23001967 3rdïstage turbine wheel or to upgrade to the Enhanced Power Turbine

design that uses P/N 23065818 3rdïstage turbine wheel. The upgrade to the

Enhanced Power Turbine requires new 3rdï and 4thïstage wheels and nozzles.

(e) Reïuse of Engines Fitted with P/N 23065833 3rdïstage Turbine Wheels Prohibited.

Engines fitted with 3rdïstage turbine wheel P/N 23065833 that have been used in any

of the affected OEM applications (A109 (all models), Soloy B206L/R, BO105 (all

models)), must not be used in any other OEM application (including nonïaffected

OEM applications) without first removing the turbine unit from service and scrapping

the 3rdïstage wheel.

(2) For OEI operation, this action is required for Model 250 Series II engines used in the

following OEM application only: Eurocopter AS355 (all models).

If an OEI condition occurs, the turbine unit of the engine operating during the event must be

immediately removed from service following the event and the 3rdïstage turbine wheel

scrapped. Replacement 3rdïstage turbine wheel options are discussed in paragraph 2.C.(1)(d).

3. MATERIAL INFORMATION ï Not applicable

CUSTOMER SUPPORT

ROLLS-ROYCE

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Revision 3

January 19, 2009

2008 RollsïRoyce Corporation

250ïC20 Series CEB Aï1400

250ïC20R Series CEB Aï72ï4095

250ïB17 Series TP CEB Aï1343

250ïB17F Series TP CEB Aï72ï2091

250ïC20 Maximum Allowable Output Shaft Speeds

FIG. 1

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December 22, 2006

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250ïC20 Series CEB Aï1400

250ïC20R Series CEB Aï72ï4095

250ïB17 Series TP CEB Aï1343

250ïB17F Series TP CEB Aï72ï2091

250ïC20B, ïC20F, ïC20J, ïC20W Maximum Allowable Output Shaft Speeds

FIG. 2

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December 22, 2006

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2008 RollsïRoyce Corporation

250ïC20 Series CEB Aï1400

250ïC20R Series CEB Aï72ï4095

250ïB17 Series TP CEB Aï1343

250ïB17F Series TP CEB Aï72ï2091

250ïB17, ïB17F, ïC20S Maximum Allowable Output Shaft Speeds

FIG. 3

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2008 RollsïRoyce Corporation

250ïC20 Series CEB Aï1400

250ïC20R Series CEB Aï72ï4095

250ïB17 Series TP CEB Aï1343

250ïB17F Series TP CEB Aï72ï2091

250ïC20R Maximum Allowable Output Shaft Speeds

FIG. 4

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Note: 

Remarks:

Informazioni: 

Information:

Al fine di gestire le varianti alla configurazione base, in relazione all’emissione del Bollettino Tecnico, preghiamo di voler compilare il presente modulo in tutte le sue parti e spedirlo all’indirizzo sopra indicato. Si ringrazia per la gentile collaborazione data. 

We request your cooperation in filling this form, in order to keep out statistical data relevant to aircraft configuration up-to-date. The form should be filled in all 

its parts and sent to the above address. We thank you beforehand for the information given.

MODULO APPLICAZIONE BOLLETTINO TECNICO

TECHNICAL BULLETIN COMPLIANCE FORM

Data: 

Date:

Numero: 

Number:

Revisione: 

Revision:

Prego spedire a questo indirizzo: 

Please send to the following address: 

AGUSTA S.p.A. 

PRODUCT SUPPORT ITALY

Via per Tornavento, 15 

21019 Somma Lombardo (VA) - ITALY 

Tel.: +39 0331 711100 

Fax: +39 0331 711180

Telefono: 

Telephone:

Fax:

Data Applicazione B.T.: 

B.T. Compliance Date:

Denominazione Cliente ed Indirizzo: 

Customer Name and Address:

Modello Elicottero 

Helicopter Model S/N Matricola Tail Number

Ore Totali 

Total Hours

Ore D.U.R. 

T.S.O.