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REV 

MODEL AFFECTED: 

SUBJECT: 

ALERT SERVICE BULLETIN~~ Ball Helicopter No. 230-07-36 

A Subsidiary ofTextron Inc. DATE JAN 09, 2007 ~ 

PAGE 1 Of8 ~ 

230 

TAIL ROTOR PITCH CHANGE MECHANISM, 

REVISED RIGGING PROCEDURES 

HELICOPTERS AFFECTED: ALL Model 230 helicopters 

COMPLIANCE: 

DESCRIPTION: 

At the next 150 hour or Annual inspection but no 

later than Dec. 31 , 2007 

It has come to the attention of Bell Helicopter Textron that due to parts tolerance 

buildup, the existing rigging procedures for the tail rotor pitch change mechanism can 

create a condition in which the position of the tail rotor counterweight bellcranks may 

not be at their optimized position to assist the flight crew with the tail rotor pedal forces 

in an emergency type operation with # 1 hydraulic system inoperative. 

This bulletin introduces a one time verification of the tail rotor pitch change mechanism 

rigging and introduces new rigging procedures for the tail rotor pitch change 

mechanism. 

APPROVAL: 

The engineering design aspects of this bulletin are Transport Canada Civil Aviation 

(TCCA) approved. 

MANPOWER: 

Approximately 2.0 man-hours are required to complete this bulletin. Man-hours are 

based on hands-on time, and may vary with personnel and facilities available. Manhour estimates do not include the man-hours required to replace the tail rotor yoke if it 

is determined that it requires replacement. 
ASB 230-07-36 

Page 2 of 8 

WARRANTY: 

Owner I Operators who have performed the inspection of the tail rotor hub outlined in 

this bulletin and could not achieve optimized positioning of the tail rotor counterweight 

bellcranks should order a replacement yoke part number 222-012-702-117. They will 

receive a pro-rated warranty credit based on a 5000 hour life limited part. If the 

lockplates part number 222-012-733-001 and 222-012-738-001 are required , 100% 

warranty credit will be allowed for the lockplates listed in the required material section 

of this ASB. 

To Receive This Credit: 

Order a replacement tail rotor yoke part number 222-012-702-117 from an approved 

Bell Helicopter Supply Source, submit a warranty claim, and a pro-rated warranty will 

be issued based on a 5000 hour life limited part. The yoke removed from service will 

have to be returned to Bell. The returned yoke will be inspected at Bell. If the yoke can 

not be reworked, the original warranty credit will be rescinded and the discrepant yoke 

will be returned to the customer at their expense in "as is condition." 

To be eligible for the credit mentioned above the ASB must be completed no later 

than 31 December 2007. 

There is no warranty credit for labor associated with this ASB. 

MATERIAL: 

Required Material: 

The following material is required for the accomplishment of this bulletin and may be 

obtained through your Bell Helicopter Textron Supply Center. 

Part Number 

222-012-733-001 

222-012-738-001 

222-012-702-1 17 

Nomenclature 

Lockplate 

Lockplate 

Tail rotor yoke 

-NOTEQuantity 

As required (Note 1) 

As required (Note 1) 

As required (Note 1 ,2) 

1. Quantities to be determined by completing 

accomplishment instructions described below 

2. Used with T/R blades P/N 222-016-001-139 only 
Consumable Material: 

None required 

SPECIAL TOOLS: 

None required 

WEIGHT AND BALANCE: 

Not affected 

ELECTRICAL LOAD DATA: 

Not affected 

REFERENCES: 

BHT-230-MM-7 Maintenance Manual 

BHT-230-MM-7 Illustrated Parts Breakdown 

T. B. 230-06-40 

PUBLICATIONS AFFECTED: 

BHT-230-MM-7 Maintenance Manual 

BHT-230-MM-7 Illustrated Parts Breakdown 

ACCOMPLISHMENT INSTRUCTIONS: 

-NOTEASB 230-07-36 

Page 3 of 8 

It is not required to verify the directional controls rigging 

before complying with this bulletin. However if you suspect 

any discrepancy with the existing directional controls rigging, 

a verification of the directional controls rigging must be 

carried out before complying with this bulletin. 

Hydraulic power is NOT required to verify the rigging of the 

tail rotor pitch change mechanism. 

Any adjustment that may be carried out to the support (6) by 

turning nut (4) and nut (8) will not change or affect the 

existing tail rotor controls/blade angle rigging settings. 
ASB 230-07-36 

Page 4 of 8 

1. Move the tail rotor pedals as required and set the pitch change housing to obtain a 

4.63 to 4.65 inches (117.6 to 118.1 mm) dimension as shown in Figure 1. Maintain 

this position. 

-NOTEThe lockplates (5 and 7) may remain in service if adjustment 

to nut (4) and nut (8) is required. However, re-bending/reusing any previously bent edge of the lockplates is not 

permitted. 

2. Verify that the centerline of counterweight bellcranks, (12, Figure 2) are parallel 

with the centerline of the tail rotor gearbox output shaft. If the counterweight 

bellcranks (12) are parallel with the centerline of the tail rotor gearbox output shaft, 

proceed to step 3. If the counterweight bellcranks (12) are not parallel with the 

centerline of the tail rotor gearbox output shaft, disconnect boot (9), pitch links (11) 

and counterweight links (1 0) as required. Straighten the bent edges of the 

lockplates (5 and 7) and adjust nut (4) and nut (8) to reposition support (6) until the 

counterweight bellcranks are parallel with the centerline of the tail rotor gearbox 

output shaft. Hold the nut (8) in position and torque the nut (4) to 50 to 55 footpounds (68 to 75 Nm). Do not bend the edge of the lockplates (5 and 7) into the 

slots of nut (4 and 8) at this time. 

-NOTETail rotor yoke P/N 222-012-702-117 incorporates a larger 

cut-out area that will provide additional clearance with nut (4) 

while maintaining the correct position of the counterweight 

bellcranks ( 12). 

Tail rotor yoke P/N 222-012-702-117 can only be used with 

tail rotor blades P/N 222-016-001-139 which incorporate the 

improved feathering bearings per T.B. 230-06-40. 

3. Move the tail rotor assembly through the full flap range (verify at both full flap 

positions). Verify if the tail rotor yoke touches the flapping stop (3) before it touches 

nut (4). If a gap exists between the tail rotor yoke and the flapping stop (3), replace 

the existing tail rotor yoke with yoke P/N 222-012-702-117. Notify BHT Product 

Support Engineering if yoke replacement is required . 

CAUTION 

Do not use standard width feeler gauges to measure the 

referenced gap as these feeler gauges are too wide and they 

do not permit measuring gaps between mating parts that 
ASB 230-07-36 

Page 5 of 8 

have a curvature. Wire type feeler gauges are best suited for 

this application. 

Due to possible variations in parts tolerances, the measured 

gap reference below shall be the smallest gap that is 

measured at any location between the tail rotor yoke and nut 

(4) when the tail rotor assembly is moved through the full 

flap range (verify at both full flap positions). 

-NOTEThere is no maximum limit on the gap that may exist 

between the tail rotor yoke and nut (4) when the pitch 

change housing is positioned as shown in figure 1 and the 

counterweight bellcranks (12) are parallel to the tail rotor 

gearbox output shaft. 

4. If there is no gap between the flapping stop (3) and the tail rotor yoke, verify if a 

0.020 inch (0.50 mm) wire type feeler gauge can be inserted between the tail rotor 

yoke and nut (4). If the smallest gap between the tail rotor yoke and nut (4) is 0.020 

inch (0.50 mm) or more, bend the edge of the lockplates (5 and 7) into the slots of 

nut (4 and 8). Connect boot (9), pitch links (11) and counterweight links (1 0) as 

required and proceed to step 6. 

-NOTEAdjusting nut (4) and nut (8) to obtain a 0.020 to 0.030 inch 

(0.50 to 0.76 mm) gap between the tail rotor yoke and nut (4) 

will result in a minor misalignment of the counterweight 

bellcranks (12) in relation to the tail rotor gearbox output 

shaft. A maximum misalignment of 1.6 degrees of the 

counterweight bellcranks (12) in relation to the tail rotor 

gearbox output shaft is acceptable when the pitch change 

housing is positioned as shown in figure 1. 

CAUTION 

Do not adjust nut (4) and nut (8) to obtain a gap of more than 

0.030 inch (0.76 mm) between the tail rotor yoke and nut (4). 

This will result in misalignment of the counterweight 

bellcranks (12) beyond the permissible maximum limit of 1.6 

degrees (in relation to the tail rotor gearbox output shaft) 

when the pitch change housing is positioned as shown in 

figure 1. This is NOT acceptable. 
ASB 230-07-36 

Page 6 of 8 

5. If the gap between the tail rotor yoke and nut (4) measures between 0.000 and 

0.019 inch (0 to 0.48 mm), adjust nut (4) and nut (8) until a gap of 0.020 to 0.030 

inch (0.50 to 0.76 mm) maximum exists between the tail rotor yoke and nut (4). 

Hold the nut (8) in position and torque the nut (4) to 50 to 55 foot-pounds (68 to 75 

Nm). Bend the edge of the lockplates (5 and 7) into the slots of the nut (4) and nut 

(8). Connect boot (9), pitch links (11) and counterweight links (1 0) as required. 

6. Examine and adjust the tail rotor pedal forces if any adjustments were carried out 

to support (6). Refer to BHT-230-MM-7, chapter 64-00-00. 

7. Annotate helicopter records to reflect compliance with this bulletin. 

8. Insert the BHT-230-MM-7 Revision 14, dated 15 Dec. 2006 into the BHT-230-MM-7 

manual. 
TAIL ROTOR GEARBOX NUT 

, ____ _ 

\ 

I 

~ I 

-t ~ 

l 

4.63 TO 4.65 IN. 

(117.6 TO 118.1 mm) 

/ 

ASB 230-07-36 

Page 7 of 8 

COUNTERWEIGHT 

BELLCRANK 

PITCH CHANGE HOUSING 

RAM 06568 _ 002 

Figure 1. Tail Rotor Pitch Change Mechanism (Position) 
ASB 230-07-36 

Page 8 of 8 

/ 

' ' ' ~ .. 

DETAILA @ 

SEE 

Q DETAILA 

1. Lockplate 222-012-738-001 

2. Nut 222-012-737-001 

3. Flapping stop 222·012·735·103 

4. Nut 222-012-731-001 

5. Lockplate 222-012-733-001 

6. Support 222·012·730·003 

7. Lockplate 222-012-733-001 

8. Nut 222-012-732-001 

9. Boot 222·012·758·001 

1 0. Counterweight link 222-012-711-ALL 

11 . T/R pitch link (all P/N) 

12. Counterweight bellcrank 

222-012-727 -ALL 

RAM 06568_001 

Figure 2. Tail Rotor Pitch Change Mechanism