DATE ALERT SERVICE BULLETIN

REVISION NOTICE

AN APPROPRIATE ENTRY SHOULD BE MADE IN TH E AIRCRAFT LOGBOOK UPON ACCOMPLISHMENT

IF OWNERSHIP OF AIRCRAFT HAS CHANGED PLEASE FORWARD TO NEW OWNER Nov 17, 2009

TO: All Owners/Operators of Bell 427 Helicopters

SUBJECT: REVISION A TO ALERT SER VICE BULLETIN 427-09-29:

TAIL ROTOR DRIVESHAFT HANG ER BEARING BRACKET P/N 427-

044-223-101, REWORK OF.

Revision A to this bulletin is issued to change the bracket web minimum thickness from

0.140 to 0.130 inch after rework.NO.

DATE

PAGE DATE

REV 

### ALERT SERVICE BULLETIN

AN APPROPRIATE ENTRY SHOULD BE MADE IN TH E AIRCRAFT LOGBOOK UPON ACCOMPLISHMENT

IF OWNERSHIP OF AIRCRAFT HAS CHANGED PLEASE FORWARD TO NEW OWNER 427-09-29

Nov 17, 09 Oct 19, 2009

A 1 of 7

MODEL AFFECTED: 427

SUBJECT: TAIL ROTOR DRI VESHAFT HANGER BEARING

BRACKET P/N 427-044-2 23-101, REWORK OF.

HELICOPTERS AFFECTED: Model 427 helicopters serial number 56001

through 56073, 56077, 5800 1, 58002 and all

spares.

Model 427 helicopters serial numbers 56074 through

56076, 56078 and subsequent and 58003 and

subsequent will have the intent of this bulletin

accomplished prior to delivery.]

COMPLIANCE: As soon as possible but no later than next

scheduled inspection or December 31, 2009

whichever comes first

DESCRIPTION:

Bell Helicopter received a report of a broken tail rotor driveshaft hanger bearing

bracket P/N 427-044-223-101. In vestigation revealed that the part fractured due to

fatigue. The crack originated in the radius near an area where a tool had cut into the

bracket for a flat faying surface. Refer to Figure 1 for details.

This Bulletin introduces a one time inspec tion of the bracket and provides rework

procedures for the polishing of both sides of the bracket. The rewo rk will eliminate the

tooling marks and increase the fatigue strength to reduce the potential for cracking in

service.

APPROVAL:

The engineering design aspects of this bulletin are Transpo rt Canada Civil Aviation

(TCCA) approved.ASB 427-09-29

Page 2 of 7

MANPOWER:

Approximately 4.0 man-hours ar e required to complete this bulletin. Man-hours are

based on hands-on time, and may vary wit h personnel and facilities available.

WARRANTY:

Owners / Operators of Bell Helico pters who comply with the inst ructions in this Bulletin

will be eligible to receive a labor credit of $300.00 towards the accomplishment of this

bulletin.

To receive this credit:

• Comply with the instructions contained in this Bulletin no later

than the applicable hours in the “c ompliance section” of this ASB,

or before December 31 2009.

• Submit an MMIR to the Bell Warranty Department.

Customers who fail to comply with the instructions in this Bulletin after the December

31 2009 are not eligible for the s pecial warranty credit listed above.

MATERIAL:

No material required

Consumable Material:

The following material is required to acco mplish this bulletin, but may not require

ordering, depending on t he operator’s consumable material stock levels. This material

may be obtained through your Bell He licopter Textron Supply Center.

Part Number Nomenclature Quantity Reference

Alodine Chemical film material A/R C-100

Scotchbrite TY A Sc otchbrite A/R C-407

SPECIAL TOOLS:

None required

WEIGHT AND BALANCE:

Not affectedASB 427-09-29

Page 3 of 7

ELECTRICAL LOAD DATA:

Not affected

REFERENCES:

BHT-427-IPB Illustra ted Parts Breakdown

BHT-427-MM Maintenance Manual, Chapter 53

BHT-427-CR&O Component Repair and Overhaul Manual

PUBLICATIONS AFFECTED:

None affected

ACCOMPLISHMENT INSTRUCTIONS:

1. Prepare the helicopter for maintenance.

2. Remove the necessary fairing and cowl assembly to gain access to the blower

housing assembly. Refer to BHT-427-MM, Chapter 53

3. Support forward end of aft shaft a ssembly P/N 427-040-325-105. Remove bolts,

washers and nuts attaching link assemb lies P/N 406-040-318-107 to aft fan shaft

bearing hanger P/N 406-040- 317-101 and hanger bracket P/N 427-044-223-101.

-NOTEDo not disturb the shims bonded on top of the support P/N

427-030-609-101.

4. Remove bolts, washers and nuts attach ing hanger bracket P/N 427-044-223-101 to

the support. Remove hanger br acket from the aircraft.

5. Clean hanger bracket. Refer to BHT-ALL-SPM.

6. Using Fluorescent Penetrant Inspecti on method, inspect affected areas of the

bracket to detect crack(s) . Refer to BHT-ALL-SPM.ASB 427-09-29

Page 4 of 7

7. Rework both side of bra cket P/N 427-044-223- 101 as follows:

a) Using 180 grit sand paper, polish out the noted machining step smooth with

the adjacent surfaces. Remove mini mum material needed to remove the

machining marks in the radius area. Maintain existing 0.50 radius and

minimum web thickness of 0.130 inch. Refer to Figure 2.

b) Polish reworked area using 280 grit s and paper. Final polish smooth reworked

area using scotchbrite (C-407).

c) Apply chemical film material (C-100) to reworked areas. Refer to BHT-ALLSPM. Refer to Figure 3.

8. Reinstall bracket on the aircraft. Refer to BHT-427-MM, Chapter 53.

9. Reinstall link assembli es P/N 406-040-318-107 to aft fan shaft bearing hanger P/N

406-040-317-101 and hanger bracket P/N 427-044-223-101. Refer to BHT-427-

MM, Chapter 53.

10. Reinstall previously removed fairing and cowl assembly.

11. Annotate the aircraft records to re flect compliance with this bulletin. AASB 427-09-29

Page 5 of 7

Machining marks on br acket P/N 427-044-223-101

Figure IASB 427-09-29

Page 6 of 7

Bracket P/N 427-044-223-101

View looking forward

Figure 2 AASB 427-09-29

Page 7 of 7

View of reworked bracket assembled on aircraft

Bracket P/N 427-044-223-101

Figure 3