DATE

ALERT SERVICE BULLETIN 

REVISION NOTICE 

A Subsidiary of Textron Inc.

AN APPROPRIATE ENTRY SHOULD BE MADE IN THE AIRCRAFT LOGBOOK UPON ACCOMPLISHMENT 

IF OWNERSHIP OF AIRCRAFT HAS CHANGED PLEASE FORWARD TO NEW OWNER

MAR 18, 2005 

TO: All Owners/Operators of Bell 212 Helicopters

 

SUBJECT: REVISION “D” TO ALERT SERVICE BULLETIN 212-00-111 (TAIL 

ROTOR BLADE 212-010-750-009 THROUGH -129 TIP BLOCK 

MODIFICATION) 

Revision “A” to this bulletin adds additional serial numbered prefix blades ATR-xxx 

and A3-xxx. All blades with serial number prefix ATR or A3 must also comply with the 

bulletin requirements. 

Revision “B” to this bulletin adds a number of serial numbered blades for the tip block 

modification. All blades with serial number A or A-FS-11530 to 13594, 13603 to 13618 

are now subject to PART B of this ASB. 

This revision also adds the procedure for removal of the tip closure rivets. 

Revision “C” to this bulletin changes the effectivity of the Tail Rotor Blades affected by 

this ASB. 

Revision “D” to this bulletin provides an alternate fastener for the tail rotor blade tip 

closure rivets installation. 

This alternate rivet P/N NAS9307M-4-01 has a monel sleeve which is more erosionresistant. Installation of this rivet with sealant MIL-PRF-81733 in lieu of adhesive 299-

947-100 TY2 CL 2 will offer a better protection against water contamination and 

corrosion. An oversize rivet P/N NAS9310M-4-01 is also added to the material list. 

Tip closure rivets installations accomplished prior to this revision are acceptable as is. 
NO. 

DATE 

PAGE 

DATE 

REV 

 

 

 

ALERT SERVICE BULLETIN 

A Subsidiary of Textron Inc.

AN APPROPRIATE ENTRY SHOULD BE MADE IN THE AIRCRAFT LOGBOOK UPON ACCOMPLISHMENT 

IF OWNERSHIP OF AIRCRAFT HAS CHANGED PLEASE FORWARD TO NEW OWNER

212-00-111 

MAR 18, 05 NOV 10, 00 

D 1 of 8 

MODEL AFFECTED: 212

SUBJECT: TAIL ROTOR BLADE P/N 212-010-750-009 

THROUGH –129, TIP BLOCK RETENTION 

MODIFICATION 

HELICOPTERS AFFECTED: All Model 212 Helicopters with Tail Rotor Blades 

P/N 212-010-750-009 through -129, (All serial 

numbers) installed require accomplishment of 

this bulletin. 

PART A of this bulletin is required only if any of the 

countersunk screws are installed below the surface 

of the abrasion strip. Refer to the inspection 

procedure. 

PART B of this bulletin is required on all tail rotor 

blades P/N 212-010-750-009 through –129. 

PART C of this bulletin provides instruction for the 

removal of the tip closure rivets if required.

[Tail rotor blade S/N A or AFS-11926, 13351, 13367, 

13393, 13400, 13402, 13515, 13540, 13568, 13595 

to 13602 and 13619 and subsequent will have the 

intent of this bulletin accomplished prior to delivery.] 

COMPLIANCE: Within the next 100 hours after receipt of this bulletin 

but no later than Dec 31, 2004.
ASB 212-00-111 

Page 2 of 8 

DESCRIPTION: 

 

Bell Helicopter has recently investigated the in-flight loss of a 212-010-750-105 tail 

rotor blade tip block. Investigation has revealed that the countersunk screws retaining 

the tip block were installed incorrectly resulting in little or no tip block retention. 

Additionally reports have been submitted of the loss of the tail rotor tip closure. 

Investigation revealed that there is a possibility of a poor adhesive bond in this area 

allowing for voiding and eventual closure loss. 

This bulletin addresses these two issues by incorporating additional fasteners in the 

tip area to prevent future loss of either the tip block or tip closure. 

 

APPROVAL: 

The engineering design aspects of this bulletin are FAA/DER approved. 

MANPOWER: 

Approximately 3 man-hours are required to complete this bulletin. Man-hours are 

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

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 A 

Part Number Nomenclature Quantity

100-159-6-2 Titanium Hi-lok Pin 2 per blade 
ASB 212-00-111 

Page 3 of 8 

PART B 

Part Number Nomenclature Quantity

M7885/2-4-01 Blind Rivet 4 per blade 

Alternate

NAS9307M-4-01 Blind Rivet 4 per blade 

M7885/6-4-01 Blind Rivet NOTE 1 

ALTERNATE

NAS9310M-4-01 Blind Rivet NOTE 1 

D

NOTE 1: Oversize rivet if required. 

Consumable Material: 

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

ordering, depending on the operator’s consumable material stock levels. This material 

may be obtained through your Bell Helicopter Textron Supply Center.

Part Number Nomenclature Quantity Reference

299-947-100TY2CL2 Adhesive Magnobond 6398 

or EA934 

A/R C-317

Denatured Solox Denatured Alcohol A/R C-326 

299-947-100TY2CL3PT Adhesive Magnobond or 

EA956 

A/R C-363

180 GRIT CLOTH Abrasive Cloth 180/220 A/R C-423 

TT-N-95,TYII 1GAL Aliphatic Naptha A/R C-305 

MIL-PRF-81733 (4 OZ) Corrosion-Inhibiting Sealant A/R C-392 

D

SPECIAL TOOLS: 

None required 

ELECTRICAL LOAD DATA: 

Not affected

REFERENCES: 

BHT-212-IPB Illustrated Parts Breakdown 
ASB 212-00-111 

Page 4 of 8 

BHT-212-MM Maintenance Manual 

BHT-212-CR&O Component Repair and Overhaul Manual 

PUBLICATIONS AFFECTED: 

BHT-212-IPB Illustrated Parts Breakdown 

BHT-212-CR&O Component Repair and Overhaul Manual 

ACCOMPLISHMENT INSTRUCTIONS 

- NOTE - 

Removal of the hub assembly from the output shaft is not 

required to remove the T/R blades. Note location and 

quantity of span balance washers for reinstallation. Remove 

any defective tail rotor blades from the T/R hub assembly in 

accordance with 212 CR&O.

Inspection Procedures

1. Deleted 

2. Inspect forward tip weight retention block and aft tip closure for voids. Remove any 

blade from service that exhibits voids in excess of CR&O limitations. 

3. Inspect forward tip block attachment countersink screws. 4 locations. See Figure 1. 

Inspect to insure that the head of the countersunk screw is flush with the surface of 

the abrasion strip. 

4. T/R blades that have the screws flush with the surface of the abrasion strip in all 4 

locations do not require shear pin installation. T/R blades with one or more of the 

screws that are set below the surface of the abrasion strip or are covered with filler 

material may not provide acceptable retention of the tip block in the event of 

adhesive failure and will require shear pin installation. The limit is flush to 0.010 

inch (0.0254 mm) high. 

5. The aft tip closure rivet installation must be accomplished on all tail rotor blades.
ASB 212-00-111 

Page 5 of 8 

PART A 

Shear Pin Installation 

- NOTE - 

Only those blades identified with countersink screws below 

the surface of the abrasion strip require the shear pin 

installation. Do not use cutting oil during drilling 

operation. Do not drill through opposite side of blade.

1. Using a clean, sharp No. 7 drill bit, drill a .50 inch deep shear pin installation hole 

as shown on Figure 1. The upper surface of the blade can be identified as the 

curved side of the blade and is same side as the data plate. Likewise the lower 

surface of the blade is the most flat side of the blade. The shear pin installation 

holes are located at 2.0 inches (projected) aft of the leading edge on the upper 

surface and 1.5 inches (projected) aft of the leading edge on the lower surface. 

2. When drilling, it is acceptable to have contact with brass master balance weights 

installed in the tip block. Once drilling is completed insure that the hole is 

thoroughly deburred and the depth and fit of the shear pin is verified. 

3. Clean shear pins 100-159-6-2 and drilled holes in blade with denatured alcohol or 

naphtha. Mix adhesive 299-947-100 TY 2 CL 2 (Hysol EA 934 or Magnobond 

6398) in accordance with manufactures instructions. Coat shear pin shanks and 

drilled hole with adhesive. Insert shear pin into hole insuring that head of shear pin 

is seated firmly with the surface of abrasion strip. Clean off excess adhesive 

leaving a small filet of adhesive squeeze-out around shear pin head to insure blade 

is sealed. Allow to cure at room temperature for 24 hours at 70-80 degrees F. 

 PART B 

Aft Tip Closure Rivet Installation 

- NOTE - 

All tail rotor blades must have the following accomplished.

Do not use cutting oil during drilling operation. Do not 

drill through opposite side of blade.

1. Using a clean, sharp no.30 drill bit, drill two rivet installation holes on both the 

upper and lower surface of the blade tip as shown in Figure 1. It is not necessary 

to remove the paint in the area. 
ASB 212-00-111 

Page 6 of 8 

2. De-burr drilled holes and verify rivet fit. Clean M7885/2-4-01 or NAS 9307M-4-01 

rivets and drilled holes with Aliphatic Naphtha. Wipe dry before solvent evaporates. 

D

3. Obtain a kit of sealant per MIL-PRF-81733. Thoroughly mix the accelerator, add it

to the base product, then thoroughly mix the mixture until a uniform color, devoid of

streaks, is achieved. 

4. Coat rivet-shanks with MIL-PRF-81733 sealant and install verifying that rivet heads

are seated firmly with blade skin. Allow a fillet of adhesive to squeeze out around 

rivet heads to insure blade is sealed. 

5. Allow sealant to cure for 24 hours at room temperature. Refinish rivet heads in 

accordance with 212 MM for blade refinishing. Re-identify the modified blade by 

the addition of "FM" after the part number (i.e., 212-010-750-109FM). 

6. Reinstall T/R blades onto the T/R hub assembly in accordance with 212 CR&O. 

Note the location of the span balance washers removed and reinstall in exact 

location where removed. 

7. Dynamically balance T/R in accordance with 212 MM and annotate historical 

records to indicate compliance with this bulletin. 
ASB 212-00-111 

Page 7 of 8 
ASB 212-00-111 

Page 8 of 8 

PART C 

Removal of tip closure rivets 

1. Remove paint and filler from around rivets using 180/220-grit sandpaper without 

damaging the skin. 

2. Using a sanding disk, carefully remove approximately half the rivet head(s) (in 

height). 

3. Using a 3/32-inch parallel punch, tap the stem(s) inside the tip closure area. 

4. Using the same punch, pry out the remainder of the stem locking ring(s). 

5. Using a clean sharp #30 drill bit, drill nearly through the remainder of the rivet 

head(s) to weaken them. 

6. Break the head(s) off, using a small chisel or the parallel punch. 

7. Using a 1/8-inch parallel punch, carefully drive the rivet shank(s) inside the tip 

closure area. 

8. Clean area to receive new rivet(s). 

9. Inspect hole(s) for size. The hole diameter should be 0.129 to 0.132-inch. If 

any hole is elongated but no larger than 0.146-inch diameter, oversize rivets 

P/N M7885/6-4-01 or P/N NAS9310M-4-01 are permissible. Drill hole(s) using 

a clean sharp #27 drill bit and deburr. 

Note 

It is recommended that the loose stem(s) and shank(s) be glued 

inside the closure area to prevent rattling. Inject a small quantity 

of C-363 adhesive through one rivet hole and move the blade in

all directions until all loose parts stop rattling. Allow adhesive to 

cure. 

D

10. Refer to PART B for rivet installation.