ASB 206L-09-158B Page 1 of 15

ECCN EAR99 ALERT SERVICE BULLETIN 206L-09-158 9 April 2009 Revision A, 31 August 2009 Revision B, 1 June 2011

MODEL AFFECTED: ALL 206L SERIES HELICOPTERS

SUBJECT: AIRWORTHINESS IN SPECTION LIMITATION TO

TAILBOOM LEFT UPPER ATTACHMENT FITTING

P/N 206-032-409-001.

HELICOPTERS AFFECTED: Serial number 45004 through 45790 and 46601 through 46617, 51001 through 51612, 52001 and subsequent equipped with tailboom assemblies listed in Appendix “A”.

COMPLIANCE: PART I: At the next 100- hour scheduled inspection and every period thereafter not exceeding 110 hours of flight time.

PART II: When loose (working) rivets, a crack or mechanical damage is found on subject fitting following inspection under PART I.

DESCRIPTION:

This Alert Service Bulletin introduces a Ch apter 4 limitation to the 100 Hours/Annual inspection currently published in the Chapter 5 of applicable 206L series maintenance manuals for the upper left tailboom attachm ent fitting Part Number 206-032-409-001.

PART I of this bulletin ela borates the Chapter 4 inspecti on requirements of the upper left tailboom attachment fitting 206-032-409- 001 and provides guidance to repair minor acceptable damage.

Part II of this bulletin prov ides guidance to replace loose (w orking) rivets or to replace the fitting in case unacceptable damage is found.

Revision “A” to this Alert Service Bull etin did introduce new damage limits and machining rework process for the fitting, clarified the inspection procedure and

corrected the reference manuals. Revision “B ” extends the inspec tion requirements to 110 flight-hours to align with the 100-hour scheduled ins pection tolerance.ASB 206L-09-158B Page 2 of 15

ECCN EAR99 APPROVAL:

The engineering design aspects of this bulletin are Transport Canada Civil Aviation (TCCA) approved.

CONTACT INFO:

For any question regarding this bulletin, please contact:

Bell Helicopter Product Support E ngineering - Light Helicopters Tel: 450-437-2862 / 1-800-363-8023 / pse light@bellhelicopter.textron.com

MANPOWER:

No additional manpower is requ ired to complete Part I of this bulletin when carried out as part of the periodic 100- hour/Annual scheduled inspection. Approximately 8 manhours are required to complete PART II of th is bulletin. Man-hou rs are based on handson time and may vary with personnel and facilities available.

WARRANTY:

There is no warranty credit applicable for parts or labor associated with this bulletin.

MATERIAL:

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 Qty Reference * P-P-101 Abrasive pape r(400 grit) A/R C-423 MIL-C-87936,TY I Aircraft soap cleaner 1 C-318 MIL-C-81706 1 QT Chemical treatment (Alodine) 1 C-100 MIL-PRF-23377TI,CLC Primer 1 C-204

* C-XXX numbers refer to the co nsumables list in BHT-ALL-SPM Standard Practices Manual

REFERENCES:

BHT-206L-SERIES-IPB Illustra ted Parts Breakdown (Rev 4, dated 12 June 2007) BHT-206L-MM-1 Maintenance Manual (Rev 34) BHT-206L1-MM-1 Maintenance Manual (Rev 31) BHT-206L3-MM-1 Maintenance Manual (Rev 17)ASB 206L-09-158B Page 3 of 15

ECCN EAR99 BHT-206L4-MM-1 Maintenance Manual (Rev 14) BHT-206L4T-MM-1 Maintenance Manual (Rev 8)

BHT-ALL-SPM Standard Practices Manual (Rev 2, dated 16 February 2007) BHT-206-SRM-1 Structural Repair M anual (Rev 1, dated 04 April 1995)

PUBLICATIONS AFFECTED:

BHT-206L-MM-1 Maintenance Manual, Chapter 4 BHT-206L1-MM-1 Maintenance Manual, Chapter 4 BHT-206L3-MM-1 Maintenance Manual, Chapter 4 BHT-206L4-MM-1 Maintenance Manual, Chapter 4 BHT-206L4T-MM-1 Maintenance Manual, Chapter 4

ACCOMPLISHMENT INSTRUCTIONS:

PART I: VISUAL INSPECTION OF TAILBOOM UPPER LEFT ATTACHMENT

FITTING 206-032-409-001.

1. Gain access to the four tailboom atta chment fittings, intercostals and bulkheads (BS 31.87 and BS 42.59) insi de the tailboom assembly by removing the tailboom access cover on the right side of the aft fuselage.

-NOTEMake sure that each drain hole on lower skin of tailboom assembly, aft of each bulkhead, is free of dirt or debris and not clogged.

2. (Ref. Figure 1) Inspect and mark head of any visible loose rivet found on attachment fittings with indelible ink felt pen before cleaning the complete tailboom attachment area with aircraft soap (C -318). Prepare soap solution per

manufacturer’s recommendations to remove all traces of dirt, stains, exhaust

residues and oil. Rinse area wit h water and let area to dry.

-NOTEIf a crack is found in the upper left tailboom attachment fitting during the inspection describ ed below, contact Product Support Engineering with deta ils before installing a new fitting.

3. (Ref. Figure 2) Use a bright light sour ce with a mirror and inspect visually the left upper tailboom attachment fitting P/N 206- 032-409-001 for loose (working) rivets,ASB 206L-09-158B Page 4 of 15

ECCN EAR99 corrosion, condition and mechanical damag e. Pay close attention on each leg of the fitting for a crack near the two most forward vertical rows of rivets.

4. If a crack, loose (working) rivets, is found on upper left attachment fitting, accomplish PART II of this bulletin.

5. If corrosion or mechanical damage is f ound on the fitting, refe r to FIGURE 2 to

determine if the fitti ng can be repaired.

a. If damage is beyond repairable condition, re place the fitting in accordance with

PART II.

b. Repair acceptabl e damage as follows;

-NOTEDepth of repair shall be twice the depth of corrosion not to exceed the repair limit s of Figure 2.

(1) Machine or sand the damage on the fi tting in order to remove minimum material. A 20:1 width to depth ratio should be maintained. Electrical discharge and electro-chemical machining are not approved. If machining is chosen, lubricant and slow machini ng shall be used to prevent generating

excessive heat that could affect existing heat treatment.

(2) If damage is affecting the corner r adius area of the fitting (see doublehatched area), blend to obtain minimu m chamfer that will remove the damage. A maximum of 0.020 inch (0.508 mm) X 45° chamfer is allowed.

(3) If damage removal is needed on inner end pad surface, ensure that the blend area is wide enough to guarantee t hat the tailboom attachment bolt

head will sit on flat surface. Do not ma chine into the fitting radius. After machining or sanding, both end pad surf aces must be parallel and lie in plane within 0.002” inch (0.050 mm).

(4) Use Sanding paper (C-423) 400 grit or finer to obtain a final surface finish of

32 RMS or better.

(5) Perform Fluorescent Penetrant Inspec tion of the fitting after blending is accomplished to ensure all damage is removed. Clean fitting to remove

fluorescent Penetrant a fter inspection is done.

(6) Apply chemical film treatment (C- 100) to bare metal surfaces, followed by

one coat minimum of primer (C-204).ASB 206L-09-158B Page 5 of 15

ECCN EAR99 6. If no crack, loose (working) rivets, corrosion or mechanical damage is found, complete the 100-hour/annual scheduled ins pection of the tailboom assembly as defined in Chapter 5 of your maintenance manual.

7. Make an entry in helicopter historical service records indicating compliance with
Part I of this Alert Service Bulletin

8. Repeat PART 1 at recurring intervals not exceeding 110 hours of flight time.

PART II: REPLACEMENT OF LOO SE (WORKING) RIVETS OR TAILBOOM

ATTACHMENT FITTING

2. Remove the upper left tailboom attachment fitting and the two mating intercostals as an assembly from the tailboom in accordance with procedure 6-3-1 of the Structural Repair Manual (BHT-206-SRM-1). If damage to fitting justifies its replacement, continue with the procedur e 6-3-1 of the SRM manual (BHT-206- SRM-1).

3. If loose (working) rivets we re found while performing ins pection as per Part I of this bulletin, proceed as follows:

a. Drill and remove the affected original MS20470DD5 (ice box rivets) or the

MS20470E5 rivets.

b. Inspect each affected hole(s) for dimens ion in accordance with Table 3-4 in the SRM manual (BHT-206-SRM-1). If affected hole(s) is/are within acceptable limits, go to Step 3. If holes are oversize or elongated, go to step 4.

-NOTEWhen re-installing the same original type and size (5/32) solid rivets as delivered from the factory, no restriction

exists. Proceed with the installati on of the rivet(s) within the fitting/intercostals assembly as per the procedure 6-3-1 described in the SRM manual (BHT-206-SRM-1).ASB 206L-09-158B Page 6 of 15

ECCN EAR99-NOTETailbooms were delivered from the factory with either all

MS20470DD5 or all MS20470E5 as original rivets installed in fitting 206-032-409-001.

When installing oversize rivets in any leg of the fitting, only the next oversize (3/16 dia. nominal) is allowed. Refer to Step 4.

4. If the same type and size (5/32 diameter) ri vet(s) are to be installed again, refer to the procedure 6-3-1 defined in the SR M manual (BHT-206-SRM-1) before proceeding with Step 6 below.

-NOTEWhen installing oversize or different type of rivets common to one leg of the fitting, it is not necessary to replace (match) corresponding rivets in opposite leg of the fitting.

5. If different type or size of rivets from fa ctory original (5/32 di a.) are required due to hole(s) beyond the acceptable limit of Table 3-4 of the SRM manual (BHT-206- SRM-1), you can install either MS20470DD or MS20470E (5/32 dia. ) rivet types or its oversize (3/16 dia.) in the fitting pr ovided the following restrictions are met:

a. A minimum of 2D edge distance shall be maintained on all rivets replaced.

b. 4d minimum pitch shall be maintained between all rivets.

c. No rivet bigger than 3/16 diameter ar e allowed in any leg of the fitting.

d. No rivets shall interf ere with the installation of the hardware securing the tailboom assembly to the fuselage.

e. No rivets should be located in the radii of the fitting.

f. (Ref. Figure 3) Whenever one orig inal 5/32 fasteners needs oversize replacement, all the rivets in that affe cted rivet group (Group “A ”, “B” or “C”) are to be replaced with the same type and size of oversize fastener.ASB 206L-09-158B Page 7 of 15

ECCN EAR99 g. It is acceptable to have a mix of “DD” and “E” type rivets in the same leg of the fitting as shown as group “D” but it is not acceptable to have such a mix within rivet respective groups “A”, “B” or “C”.

Example 1: (Ref, Figure 3) A rivet hole in part of group “A” is elongated (oversize); both rivets in group “A” must be replaced.

Example 2: (Ref. Figure 3) Two rivet holes, one in group “A” and the other in group “B” are elongated (oversize); all rivets in both groups (“A” and “B”) must be replaced. Although the rivets in group “C” do not require to be changed, it is acceptable if the operator chooses to replace those as well.

6. Re-install the fitting and intercostals assembly back into the tailboom using the procedure 6-3-1 of the SRM manual (BHT-206-SRM-1).

7. Make an entry in helicopter historical service records indicating compliance with
Part II of this Alert Service Bulletin.ASB 206L-09-158B Page 8 of 15

ECCN EAR99 NOTES 1. Inspect upper left attachment fitting P/N 206-032-409-001 for a crack, corrosion, loose rivets, mechanical damage and general condition within a period not to exceed 110 hours of flight time. 2. Repair fitting in accordance with PART I and Figure 2 provided limitations are met after

rework. 3. Replace cracked or damaged fitting or loose rivets in accordance with Part II of this

bulletin.

4. Tailboom assembly remaining details not shown for clarity.

5. If a crack is found, replace damaged fitting in accordance with paragraph 6-3-1 of the Structural Repair Manual (BHT-206-SRM-1).

FIGURE 1: INTRODUCTION OF AIRW ORTHINESS INSPECTION LIMITATION TO

TAILBOOM ATTACHMENT FITTING P/N 206-032-409-001ASB 206L-09-158B Page 9 of 15

ECCN EAR99 FIGURE 2: DAMAGE LIMITATION AND APPROVED REPAIR TO FITTING P/N 206-032-409-001 (Sheet 1 of 2).ASB 206L-09-158B Page 10 of 15

ECCN EAR99 FIGURE 2: DAMAGE LIMITATION AND APPROVED REPAIR TO FITTING P/N 206-032-409-001 (Sheet 2 of 2).ASB 206L-09-158B Page 11 of 15

ECCN EAR99 NOTES: When re-installing the same original type and size (5/32) solid rivets as delivered from the factory, no restriction exist. Proceed with the installation of the rivet(s) within the fitting and intercostals assembly and re-install unit within the tailboom as per the remaining steps of the procedure 6-3-1 found in the SRM manual.

When installing oversize or different type of rivets common to one leg of the fitting, it is not necessary to replace (match) corresponding rivets in opposite leg of the fitting.

When different type or size of rivets from factory original are required due to hole(s) beyond

the limit of Table 3-4 of the SRM where over size rivet(s) is/are needed, any number of different type or oversize rivets can be installed provided the following restrictions are met:

a. Either MS20470DD or MS20470E rivet type may be used as replacement. Only these two can

be used. b. A minimum of 2D edge distance shall be maintained on all rivets replaced. c. 4D minimum pitch shall be maintained between all rivets. d. No rivet bigger than 3/16 diameter ar e allowed in any leg of the fitting.

e. No rivets shall interfere with the installation of the hardware securing the tailboom assembly to the fuselage. f. No rivets should be located in the radii of the fitting. g. Whenever one original 5/32 fa steners needs oversize replacement, all the rivets in that affected rivet group (Group “A”, “B” or “C”) are to be r eplaced with the same type and size of oversize

fastener. h. It is acceptable to have a mix of “DD” and “E” type rivets in the same leg of the fitting as shown as group “D” but it is not acceptabl e to have such a mix within rivet respective groups “A”, “B” or
“C”. Example 1: A rivet hole in part of group “A” is elongated (oversize); both rivets in group “A” must be replaced. Example 2: Two rivet holes, one in group “A” and the other in group “B” are elongated (oversize); all rivets in both groups (“A” and “B”) must be replaced. Although the rivets in group “C” do not require to be changed, it is acceptable if the operator chooses to replace those as well.

FIGURE 3: REPLACEMENT OF LOO SE (WORKING) RIVETS IN TAILBOOM

ATTACHMENT FITTING P/N 206-032-409-001ASB 206L-09-158B Page 12 of 15

ECCN EAR99 

## APPENDIX “A”
DESCRIPTION OF TAILBOOM PART NUMBERS:

206-033-004-003: Basic tailboom part number (see Note below) as delivered on 206L model S/N 45003 through 45076.

206-033-004-003FM: Basic tailboom modified under ASB 206L-87-47 (Addition of one piece driveshaft cover clip and doubler on upper skin)

206-033-004-003FM1: -003FM configuration upgraded to -045 equivalence under TB 206L-90-

150.

206-033-004-003FM2: -003FM configuration upgraded to -177 equivalence under TB 206L-96-

191.

206-033-004-003FMA: -003FM configuration which has complied also with ASB 206L-99- 115(Addition of a riveted doubler at left horizontal stabilizer cutout).

206-033-004-003FM1A: -003FM configuration upgraded to -045 equivalence under TB 206L90-150 which has complied also with ASB 206L-99 -115(Addition of a riveted doubler at left horizontal stabilizer cutout).

206-033-004-003FM2A: -003FM configuration upgraded to -177 equivalence under TB 206L96-191 which complied with ASB 206L-99-115(Additi on of a riveted doubler at left horizontal stabilizer cutout).

Note: The basic tailboom part number on the data plate could have been identified also with a suffix “A” from the factory. This suffix is not taken into ac count for the part numbers above representing field

modifications as described herein.



## 206-033-004-011: Basic tailboom part number (see Note below) as delivered on 206L model S/N 45077 through 45153 and S/N 46601 through 46617.

206-033-004-011FM: Basic tailboom modified under ASB 206L-87-47 (Addition of one piece driveshaft cover clip and doubler on upper skin).

206-033-004-011FM1: -011FM configuration upgraded to -045 equivalence per BHT

instructions letter.

206-033-004-011FM2: -011FM configuration upgraded to -103 equivalence per BHT

instructions letter.

206-033-004-011FM3: -011FM configuration upgraded to -045 equivalence under TB 206L-90-

150.

206-033-004-011FM4: -011FM configuration upgraded to -177 equivalence under TB 206L-96-

191.

206-033-004-011FMA: -011FM configuration which complied also with ASB 206L-99- 115(Addition of a riveted doubler at left horizontal stabilizer cutout).

206-033-004-011FM1A: - 011FM configuration upgraded to -045 equivalence per BHT instructions letter which complied also with ASB 206L-99-115(Addition of a riveted doubler at left horizontal stabilizer cutout).

206-033-004-011FM2A: -011FM configuration upgraded to -103 equivalence per BHT instructions letter which complied also with ASB 206L-99-115(Addition of a riveted doubler at left horizontal stabilizer cutout).

206-033-004-011FM3A: -011FM configuration upgraded to -045 equivalence under TB 206L90-150 which complied also with ASB 206L-99- 115(Addition of a riveted doubler at left horizontal stabilizer cutout).ASB 206L-09-158B Page 13 of 15

ECCN EAR99 206-033-004-011FM4A: -011FM configuration upgraded to -177 equivalence under TB 206L96-191which complied with ASB 206L-99-115(Addit ion of a riveted doubler at left horizontal stabilizer cutout).

Note: The basic tailboom part number on the data plate could have been identified also with a suffix “A” from the factory. This suffix is not taken into ac count for the part numbers above representing field

modifications as described herein.



## 206-033-004-103: Basic tailboom part number (see Note below) as delivered on 206L model S/N 45154 through 45283.

206-033-004-103FM: Basic tailboom modified under ASB 206L-87-47 (Addition of one piece driveshaft cover clip and doubler on upper skin).

206-033-004-103FM1: -103FM configuration upgraded to -045 equivalence under TB 206L-90-

150.

206-033-004-103FM2: -103FM configuration upgraded to -177 equivalence under TB 206L-96-

191.

206-033-004-103FMA: -103FM configuration which complied also with ASB 206L-99- 115(Addition of a riveted doubler at left horizontal stabilizer cutout).

206-033-004-103FM1A: -103FM configuration upgraded to -045 equivalence under TB 206L90-150 which complied also with ASB 206L-99- 115(Addition of a riveted doubler at left horizontal stabilizer cutout).

206-033-004-103FM2A: -103FM configuration upgraded to -177 equivalence under TB 206L96-191 which complied with ASB 206L-99-115(Additi on of a riveted doubler at left horizontal stabilizer cutout).

Note: The basic tailboom part number on the data plate could have been identified also with a suffix “A” from the factory. This suffix is not taken into ac count for the part numbers above representing field

modifications as described herein.



## 206-033-004-045: Basic tailboom part number( see Note below) as delivered on 206L-1 model S/N 45284 through 45790 and on 206L-3 model S/N 51001 through 51283.

206-033-004-045FM: Basic tailboom modified under ASB 206L-87-47 (Addition of one piece driveshaft cover clip and doubler on upper skin)

206-033-004-045FM1: -045FM configuration upgraded to -143 equivalence per BHT

instructions letter.

206-033-004-045FM2: -045FM configuration upgraded to -177 equivalence under TB 206L-96-

191.

206-033-004-045FMA: -045FM configuration which complied also with ASB 206L-99- 115(Addition of a riveted doubler at left horizontal stabilizer cutout).

206-033-004-045FM1A: 045FM configuration upgraded to -143 equivalence per BHT instructions letter which complied with ASB 206L-99-115(Addition of a riveted doubler at left horizontal stabilizer cutout).

206-033-004-045FM2A: -045FM configuration upgraded to -177 equivalence under TB 206L96-191 which complied with ASB 206L-99-115(Additi on of a riveted doubler at left horizontal stabilizer cutout).ASB 206L-09-158B Page 14 of 15

ECCN EAR99 Note: The basic tailboom part number on the data plate could have been identified also with a suffix “A” from the factory. This suffix is not taken into ac count for the part numbers above representing field

modifications as described herein.



## 206-033-004-143: Basic tailboom part number (see Note below) as delivered on 206L-3 model S/N 51284 through 51612.

206-033-004-143FM1: Basic tailboom upgraded to -177 equivalence under TB 206L-96-191.

206-033-004-143FM1A: -143FM configuration upgraded to -177 equivalence under TB 206L96-191 which complied with ASB 206L-99-115(Additi on of a riveted doubler at left horizontal stabilizer cutout).

Note: The basic tailboom part number on the data plate could have been identified also with a suffix “A” from the factory. This suffix is not taken into ac count for the part numbers above representing field

modifications as described herein.



## 206-033-004-175: Basic tailboom part number (see note below) as delivered on 206L-4 model S/N 52001 through 52026.

206-033-004-175FM1: Basic tailboom upgraded to -177 equivalence under TB 206L-96-191.

206-033-004-175FM1A: -175FM configuration upgraded to -177 equivalence under TB 206L96-191 which complied with ASB 206L-99-115(Additi on of a riveted doubler at left horizontal stabilizer cutout).

Note: The basic tailboom part number on the data plate could have been identified also with a suffix “A” from the factory. This suffix is not taken into ac count for the part numbers above representing field

modifications as described herein.



## 206-033-004-177: Basic tailboom part number (see Note below) as delivered on 206L-4 model S/N 52027 through 52232.

206-033-004-177A: Basic tailboom which complied with ASB 206L-99-115(Addition of a riveted doubler at left horizontal stabilizer cutout).

Note: The basic tailboom part number on the data plate could have been identified also with a suffix “A” from the factory.



## 206-033-004-181: Basic tailboom part number (see Note below) as delivered on 206L-4 models S/N 52233 through 52245.

Note: The basic tailboom part number on the data plate could have been identified also with a suffix “A” from the factory.



## 206-033-004-199: Basic tailboom part number (see Note below) as delivered on 206L-4 models S/N 52246 through 52340.ASB 206L-09-158B Page 15 of 15

ECCN EAR99 Note: The basic tailboom part number on the data plate could have been identified also with a suffix “A” from the factory.



## 206-033-004-203: Basic tailboom part number (see Note Below) as delivered on 206L-4 model S/N 52341 through subsequent.

Note: The basic tailboom part number on the data plate could have been identified also with a suffix “A” from the factory.



## 206-704-727-103: Any tailbooms listed above upgraded to -199 part number equivalence by BHT-Approved Customer Service Facilities CSF) holding copies of drawings 206-530-127 and 206-704-727. This upgrade involves replacement of the upper ski n along with meeting compliance with TB 206L96-191 as the initial baseline. 

## 206-704-727-105: Any tailbooms listed above upgraded to -199 part number equivalence by BHT-Approved Customer Service Facilities CSF) holding copies of drawings 206-530-127 and 206-704-727.This upgrade involves replacement of the lower skin along with meeting compliance with TB

206L-96-191 as the initial base line.



## 206-704-727-101: Any tailbooms listed above upgraded to -199 part number equivalence by BHT-Approved Customer Service Facilities CSF) holding copies of drawings 206-530-127 and 206-704-727.his upgrade involves replacement of both the upper and lower skins along with meeting compliance with TB 206L-96-191 as the initial baseline.