DATE 

### ALERT SERVICE BULLETIN

REVISION NOTICE

A Subsidiary of Textron Inc.

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

IF OWNERSHIP OF AIRCRAFT HAS CHANGED PLEASE FORWARD TO NEW OWNER AUG 27, 2007

TO: All Owners/Operators of Bell 407 Helicopters

SUBJECT: REVISION “C” TO ALERT SERVICE BULLETIN 407-01-48: (TAILBOOM ASSEMBLY 407-030- 801-101, /-105, /-107, MODIFICATION OF, AND NEW AIRWORTHINESS

LIMITATION/INSPECTION SC HEDULE, INTRODUCTION OF.)

Revision “C” to this bulletin makes the changes that follows:

• Clarifies that once a tailboom 407-530-014-101,/-103 or 407-030-801-107

reaches 5000 hours in servic e, it cannot have a new skin installed and must be

retired.

• Replaces the inspection requirements as guided under PAR T IV and PART V. Operators/maintainers are now instructed to refer to new inspection requirements for modified tailbooms 407-530-014-101, /-103 and 407-030-801-107 as defined

under Alert Service Bulletin 407-07-80

.NO.

DATE

PAGE DATE

REV 

### ALERT SERVICE BULLETIN

A Subsidiary of Textron Inc.

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

IF OWNERSHIP OF AIRCRAFT HAS CHANGED PLEASE FORWARD TO NEW OWNER 407-01-48

AUG 27, 2007 20-12-01

C 1 of 32

MODEL AFFECTED: 407

SUBJECT: TAILBOOM ASSEMBLY 407-030-801-101, /-105, /-107 MODIFICATION OF, AND NEW

AIRWORTHINESS LIMI TATION/INSPECTION SCHEDULE, INTRODUCTION OF.

HELICOPTERS AFFECTED: 407, Serial Number 53000 through 53475.

[Helicopters Serial Nu mber 53476 and subsequent have been delivered with tailboom assembly 407- 030-801-201 or later part number installed, and are not affected by this bulletin]

[Helicopters Serial Number 53000 through 53475 that have spare tailboom assembly 407-030-801- 201 or later part number inst alled, are not affected by this bulletin]

COMPLIANCE: 1. Immediately upon receipt of this bulletin if

tailboom 407-030-801-107 is installed. As directed by Parts IV and V of this bulletin.

2. No later than 31 J anuary 2003 if tailboom 407-

030-801-101 or /-105 is instal led. As directed by Parts I through III of this bulletin.

-NOTEYou must ensure that the intent of Technical Bulletin 407- 01-33 is met at the same time as you do this bulletin.

Continue to examine the tailbooms assemblies 407-030-

801-101 and /-105 in accordance with Alert Service Bulletin 407-99-26, Revision C or la ter revision until you have complied with this bulletin.ASB 407-01-48 Page 2 of 32

DESCRIPTION:

Since release of ASB 407-99-26, Bell Helicopter has received additional reports of tailboom upper skins found cracked in se rvice. Cracks were found during daily inspection or scheduled maintenance. The cr acks originated from the holes where the fasteners (NAS1738MW5) are installed at the forward and aft section (B.S. 98.89 and B.S. 120.75 respectively) of the le ft upper stabilizer support 407-023-800-117.

This bulletin gives instructions to remo ve sixteen fasteners on the left side of the tailboom only, do an inspection of each ho le by Eddy Current method and install

oversize fasteners. It also assigns a new airworthiness life to the specific tailbooms and introduces new inspection requirements.

PART I gives instructions to inspect by Ed dy Current method, and modify with new fastener type, the tailboom s 407-030-801-101, /-105. T he tailboom 407-030-801-107

meets the intent of this bu lletin and does not require inspection and modification.

Part II makes mandatory the installation of the horizontal stabil izer by improved method introduced by Techni cal Bulletin 407-01-33.

Part III assigns new part numbers to the ta ilbooms 407-030-801-101, /-105 that have

been modified. Those modified tailbooms are considered equivalent to, and interchangeable with, the /-107 configuration.

Part IV assigns a service life of 5000 hour s since new to tailboom 407-030-801-107

and 5000 hours from time of rework to modified tailbooms 407-530-014-101, /-103 and guides owners/operators to applic able inspection requirements.

Part V of this bulleting giving new inspection requirements applicable for the modified tailbooms 407-530-014-101, /- 103 and tailboom 407-030-801-107 is being cancelled and replaced by new inspection requirement s as defined under Alert Service Bulletin

407-07-80.

APPROVAL:

The engineering design aspects of this bulletin are Transport Canada approved.

MANPOWER:

Approximately 10.0 man-hours are necessary to complete PART I of this bulletin. Man-hours are based on hands-on time, and can vary with personnel and facilities

available. C.ASB 407-01-48 Page 3 of 32

WARRANTY:

Owners/operators of 407 helicopters who comply with the instructions outlined in this bulletin will receive a special 100% warrant y credit for the PART I kit contained in the “Required Material” section of th is bulletin. In addition, labor to incorporate the PART I kit will be allowed in the amount of $600 USD.

Special Warranty Note

Owners/Operators of 407 helic opters that are required to incorporate Technical

Bulletin 407-01-33 will receiv e a special 100% warranty cr edit for the parts contained in the “Required Material” section of that bu lletin. In addition, labor to incorporate that

bulletin TB 407-01-33 will be allow ed in the amount of $480 USD.

To receive this credit:

 Purchase the required parts from a BHTI-approved supply source.

 Place your order no la ter than 30 September 2002.

 Submit a completed malf unction report to BHTI Wa rranty no later that 30 days after completion of this bulletin.

Note: Customers who fail to order parts for this bulletin before 30 September 2002 are

not eligible for the special warrant y credit provisions listed above.

MATERIALS:

The following material is needed to modify tailboom assemblies 407-030-801- 101, /-105 only. If you have tailboom 407- 030-801-107, you do not need to order the parts.

Required Material:

The material that follows is necessary to complete this bulletin and can be procured through your Bell Helicopter Textron Supply Center.

Order hardware kit CA-407-01-48 that includes the parts that follow:

Part Number Nomenclature Quantity

M7885/2-5-02 Rivet 12

100-071-7 Identific ation plate 1

MS20604B3W1 Rivet 2 HL22093-6-4 Fastener and collar 4 (see Note 1) 110-164-1 Rivet 2 (see Note 2) B.ASB 407-01-48 Page 4 of 32

Notes:

1. Fastener and collar can be order ed separately under P/N HL220PB-6-4 and HL93-6 respectively. 2. Required for tailbooms 407-030- 801-101 that were upgraded to the equivalent of /-105 c onfiguration, in accordanc e with the BHT-Approved procedure covered by Transport Canada Approval form AE-100-1 only. See additional identification pl ate (locally manufactured) installed adjacent to the BHT identification plate.

Consumable Material:

The material that follows is necessary to co mplete this bulletin, however this material is considered consumable (bench stock) material and may not require ordering depending on the operators consum able material stock levels . This material can be procured through your Bell Helico pter Textron Supply Center.

Part Number Nomenclature Reference

MIL-PRF-81733 Sealant C-392 (Note 1) Acetone Acetone (per Q- A-51) C-316 (Note 2) MIL-P-85582, TY1, CL2 Pr imer C-204 (Note 3)

IL-C-81706 1 GAL Chem Film C-100

P-P-101 Aluminum Oxide Sandpaper C-423

150-021-10C2-4 Al A lloy 2024T3 (0.032 inch (0.81 mm) thick) N/A (Note 4)

Notes: 1. Formerly MIL-S-81733 2. As an alternative, use Me thyl Ethyl Ketone (C-309) 3. As an alternative, use MIL-P-23377 4. Use only if required. Refer to page 20 and 24 of this bulletin for details.

SPECIAL TOOLS:

 Reamer 0.1875 inch (4.7625 mm) diameter

 Reamer 0.1935 inch (4.915 mm) diameter

 Reamer 0.2185 inch (5.55 mm) diameter

 Reamer 0.1635 inch (4.15 mm) diameter

 Reamer 0.177 inch (4.50 mm) diameter

 Hocking Phasec 2200 or Zetec Mi z 20 or equivalent Eddy Current inspection equipment.

 Eddy Current probes MBD2-10/12-1WL and MBD2-12/14-1WL or equivalent tuned to a frequency between 100 KHz – 1.0 MHz.

 Eddy Current Inspection Reference St andard (calibrating coupon) part number BHTI EC-10-20 (see Note below) B.

B.ASB 407-01-48 Page 5 of 32

Note: The reference standard can be procured from BHT-Approved supply centers or from the following addresses;

EC/NDT LLC PH Tool

1020 S 344 TH , Suite 214 10 Callowhill Road Federal Way, WA 98003 New Britain, PA 18901 Tel: (877) 565-0797 Fax: (215) 822-6799 Fax: (253) 815-0827 Tel: (888) 553-9245

E-mail : EC-NDT@worldnet.att.net E-mail: sales@phtool.com

WEIGHT AND BALANCE:

Not affected.

ELECTRICAL LOAD DATA:

Not affected.

REFERENCES:

BHT-407-MM-5, Rev. 23, 07 November 2006

Chapter 53, Fuselage

BHT-407-IPB, Rev 05, 22 December 2006

Chapter 53, Fuselage

BHT-206-SRM-1, Rev. 1, 04 April 1995

BHT-ALL-SPM, Reissue, 20 August 1999

Corrosion Control Guide CSSD-PSE-87-01, issue 6 August 1987

Technical Bulletin 407-01-33
Horizontal Stabilizer 407-023-800-A LL Installation, Improvement of.

Bell Helicopter Textr on drawing number 407-799-046 C.ASB 407-01-48 Page 6 of 32

PUBLICATIONS AFFECTED:

BHT-407-MM-5, Rev. 23, 07 November 2006

Chapter 4, M andatory Retirement

Chapter 5, Inspections

Chapter 53, Fuselage

BHT-407-IPB, Rev 05, 22 December 2006

Chapter 53, Fuselage

ACCOMPLISHMENT INSTRUCTIONS:

TABLE 1

If you have the following tailboom You must comply with the following sections of this

bulletin Original tailboom P/N 407-030-801-101

or /-105 Part I, Part II, Pa rt III, Part IV

and Part V Tailboom 407-030-801-101 upgraded by BHT-Approved procedure to equivalence of /-105 configuration. Part I, Part II, Part III (see Note 2 below), Part IV and

Part V

Tailboom 407-030-801-101or /-105 modified by BHT drawing 407-799-046 Part I (see Note 1 below), Part III, Part IV and Part V

Tailboom 407-030-801-107 Pa rt IV and Part V

NOTES:

1. Tailboom inspected a nd modified in accordance with BHT drawing 407-799-046

meets the intent of Step 1 through 5 of Part I but must complete Steps 6 through 8. Following comp letion of Steps 6 through 8 of Part I, destroy identification plate install ed during the previous modi fication. Mark the new plate with applicable part number in cross-referenc e with the original BHT identification plate and insta ll in the same location.

2. For all tailbooms 407 -030-801-101 that were upgraded to equivalent of /-105 configuration, in accordance with BHT-Approved procedure covered with Transport Canada Approval form AE-100-1, remove the added identification plate that was locally manufactur ed and installed adjacent to the BHT identification plate and destr oy. Plug existing holes with two rivets 110-164-1. Mark the new plate with applicable part num ber cross-referenced by the original BHT identification plate and install at t he location indicated in this bulletin. C.ASB 407-01-48 Page 7 of 32

PART I: Inspection and modificat ion of tailboom assemblies 407-030-801- 101, /-105

-NOTETailboom assembly 407-030-801- 107 meets the intent of the inspections and modifications described in Part I of this bulletin. Part I does not apply to tailboom assembly 407-

030-801-107.

1. Initial inspection, existing fasten ers and upper stabilizer support (left stabilizer cut-out area, Ref. B.S. 98.89 and B.S. 120.75).

a. Refer to Figure 3 (Views B and C) . Examine as follows for acceptable

conditions at the affected fastener locati ons to determine if your tailboom is eligible to be modified.

(1.) Look at the left stabilizer upper s upport (3) and verify that the two upper

fasteners as shown in Views B and C are original NAS1738MW5. (Correct identification letters/number “ T, M, 04 and + ” can be seen with a magnifying glass on the head of the fa stener when paint and primer is removed). If an oversize fastener has been installed, the inspection as described by Table 2 and Appendix A cannot be done and the tailboom assembly (5) must be replaced.

(2.) Look at the left stabilizer upper s upport (3) and verify that the two lower

fasteners as shown in Views B and C are original 100-048-6 (Hi-Lok

identification number “ HL 20 6 ” can be seen with a magnifying glass on

the head of the fastener w hen paint and primer is removed). If an oversize fastener has been installed, the inspection/modification as described by Table 2 and Appendix A cannot be done and the tailboom assembly (5) must be replaced.

(3.) Examine each of the four fasten er locations for acceptable edge distance of 0.33 inch (8.38 mm) minimum. If edge distance is not acceptable, replace the existing left upper suppor t (3) and doubler (2) using part

number 407-023-800-127 and 4 07-023-800-135 respectively before you go to Part II of this bulletin.

b. If all the conditions described above are acceptable, continue with step 2.

c. If one of the conditions described above is not acceptable, contact Product Support Engineering at the numbers that follow:ASB 407-01-48 Page 8 of 32

Bell Helicopter Textron Product Support Engineering Tel: 1-800-243-6407 (Continental USA and Canada) Tel: 1-800-363-8023 (Continental USA) Tel: 1-800-361-9305 ( within Canada) Tel: 1-450-437-2862 (all other areas-call collect)

Fax: 1-450-433-0272

Internet: pselight@bellhelic opter.textron.com

2. Preparation of fastener holes for in spection by Eddy Current method (left stabilizer cut-out area, Ref. B.S. 98.89 and B.S. 120.75).

a. Refer to chapter 53-00- 00 of the maintenance manual and remove the following components:

(1.) The aft oil cooler blower fairi ng from the aft section of fuselage.

(2.) The two fiberglass driveshaft cove rs from top of tailboom assembly.

(3.) The tail rotor driveshaft assembly located between B. S. 42.00 and B.S.
75.00.

CAUTION

IF SEALANT NEEDS TO BE REMOVED, USE A THIN BLADE PUTTY KNIFE. BE CAREFUL TO NOT DAMAGE THE ELECTRIC WI RES AT THE TRAILING EDGE OF THE STABILIZER.

(4.) The left auxiliary finl et from end of stabilizer. Keep the screws for later installation.

-NOTEDo not disassemble the lower support angles from the closure plates.

(5.) Both lower stabilizer at tachment support assemblies.

CAUTION

USE PROTECTIVE DEVICE OR PADDING ON TOP OF THE ELECTRIC WIRE STAND-OFF BRACKET LOCATED ON BALLAST TRAY INSIDE THE TAILBOOM TO PREVENT DAMAGING PA INT FINISH AND/OR LOWER SURFACE OF STABILIZER.

(6.) The stabilizer (6) from the tailboom (5).ASB 407-01-48 Page 9 of 32

CAUTION

DO NOT DAMAGE OR ENLARGE HOLES DURING REMOVAL PROCESS OF THE FASTENERS.

b. Refer to Figure 3 (Vie ws B and C). Remove the upper rivet NAS1738MW5 and the Hi-Lok fastener 100-048-6 located at the front and aft end of the left stabilizer support only.

c. Refer to Table 2. Enlarge holes as follows;

CAUTION

MAKE SURE THE TOOL IS PERPENDICULAR TO THE

TAILBOOM SURFACE AT ALL TIMES WHEN YOU

DRILL OR REAM.

(1.) Initial ream each upper hole locati on (2 places), to 0.1875 inch (4.7625 mm) diameter where the fasteners NAS 1738MW5 were initially installed.

(2.) Initial ream each lower hole locati on (2 places) to 0.1935 inch (4.915 mm)

diameter where the Hi-Lok fasteners 100-048-6 were initially installed.

3. Inspection of fastener holes by Eddy Current method (left stabilizer cutout area, Ref. B.S. 98. 89 and B.S. 120.75).

-NOTEThe Eddy Current inspection procedure recommended herein by Bell Helicopter Text ron should only be used for inspection of Bell 407 tailbooms 407-030-801-101 and /-

105

a. Refer to Figure 4 (views G and H) and do the inspection of each hole by the Eddy Current inspection procedure as recommended by Attachment “A”.

(1.) If you detect a crack, remove the upper support (3) and the doubler (2) and inspect hole again to verify if the cr ack detected affects the upper tailboom skin (7) or the adjacent bulkhead. (Re f. B.S. 98.89 or B.S. 120.75). If a

crack is confined in the tailboom ski n (7) or the adjacent bulkhead, the tailboom (5) must be removed from service and replaced with a

serviceable unit.

(2.) If there is no crack detected in the tailboom skin (7) or the adjacent bulkhead. (Ref. B.S. 98.89 or B.S. 120. 75), install a serviceable doubler (2) with a serviceable support (3) before you go to step 4.ASB 407-01-48 Page 10 of 32

4. Inspection of fastener holes for interf erence with flange ra dius of bulkheads (left stabilizer cut-out area, Re f. B.S. 98.89 a nd B.S. 120.75).

a. Refer to Figure 4 (views G and H). Us e a mirror to inspect the inboard surface of the flange of each bulk head located at B.S. 98.89 and B.S. 120.75. Examine for possible interference from the new fastener retaining collar with the bend radius of each bulkhead flange.

(1.) If there is no interference, go to step 5.

(2.) Refer to Detail J. If there is inte rference, fabricate lo cally a radius block

for the affected location. Install the radius block (19) against the inboard

surface of the affected bulkhead flange before increasing the affected

holes to final dimension described in Ta ble 2. Install the radius block (19)

as follows:

(a) Find the best fit and locate the r adius block (19) against the internal

surface of the affected bulkhead fl ange. Make sure a minimum of 2D edge distance will exist at each end of the radius block.

CAUTION

MAKE SURE THE TOOL IS PERPENDICULAR TO THE

TAILBOOM SURFACE AT ALL TIMES WHEN YOU

DRILL OR REAM.

(b) Clamp the radius block (19) in pl ace and transfer the existing upper hole

initial-reamed diameter of 0.1875 inch (4.7625 mm) and lower hole

initial-reamed diameter of 0.1935 inch (4.915 mm) to the radius block.

(c) Remove the radius block (19) and deburr each hole. Apply a light coat of primer (C-204) to all bar e metal surfaces and let dry.

(d) Install temporarily the radius block (19) against the internal surface of the bulkhead flange with two Clecos until the hole final diameter is obtained.

(e) Go to step 5 and install the new fasteners HL22093-6-4.

5. Installation of new fast eners HL22093-6 (left stabilizer cut-out area, Ref. B.S. 98.89 and B.S. 120.75).

a. Refer to Figure 4 (views G and H) and T able 2. Increase the size of the holes

to their final dimension as follows: B.ASB 407-01-48 Page 11 of 32

CAUTION

MAKE SURE THE TOOL IS PERPENDICULAR TO THE

TAILBOOM SURFACE AT ALL TIMES WHEN YOU

DRILL OR REAM.

-NOTEMake sure that the radius bl ock (19), if applicable, remains undisturbed when you drill or ream.

(1.) Increase the diameter of the tw o upper holes (B.S. 98.89 and B.S 120.75)

to final reamed dimension of 0.2185 in ch (5.55 mm) diameter where the NAS1738MW5 were originally installed.

(2.) Increase the diameter of the two lower holes (B.S. 98. 89 and B.S 120.75)

to final reamed dimension of 0.2185 in ch (5.55 mm) diameter where the

Hi-Lok fasteners 100-048-6 were originally installed.

(3.) Deburr each hole and install two new fasteners HL22093-6-4 at B.S. 98- 89 and B.S. 120.75 respectively.

6. Preparation of fastener holes fo r inspection by Eddy Current method (tailboom forward area, Ref. B.S. 45.515, B.S. 58.995 a nd B.S. 72.475).

CAUTION

DO NOT DAMAGE OR ENLARGE HOLES DURING REMOVAL PROCESS OF THE FASTENERS.

a. Refer to Figure 4,View J. Remove the rivets located left of B.L. 0.0 at each of the driveshaft cover brackets insta lled at B.S 45.515, B.S. 58.995 and B.S. 72.475(4 each, total of 12 rivets).

b. Refer to Table 2. Enlarge holes as follows:

CAUTION

MAKE SURE THE TOOL IS PERPENDICULAR TO THE

TAILBOOM SURFACE AT ALL TIMES WHEN YOU

DRILL OR REAM.

(1.) Drill and ream each hole (4 per br acket, 3 places, total of 12 holes) to 0.1635 inch (4.15 mm) diameter wher e the fasteners M7885/6-4-02 were initially installed.

(2.) Deburr edges of each hole.ASB 407-01-48 Page 12 of 32

7. Inspection of fastener holes by Eddy Current method (tailboom forward area, Ref. B.S. 45.515, B.S. 58.995 and B.S. 72.475).

-NOTEThis inspection must also be completed on tailbooms modified and identified in accordance with BHT drawing

407-799-046.
-NOTEThe Eddy Current inspection procedure recommended herein by Bell Helicopter Text ron should only be used for inspection of Bell 407 tailbooms 407-030-801-101 and /-

105

a. Refer to Figure 4, View J. Do the inspection of ea ch hole (4 per bracket, 3 places, total of 12 holes) by Eddy Current inspection procedure as

recommended in Attachment “A”.

(1.) If you detect a crack in the tailboom skin (7), the tailboom (5) will have to be removed from service and replaced with a serviceable unit.

(2.) If there is no crack det ected in the tailboom skin (7), install new fasteners M7885/2-5-02 wet with unreduced primer (C-204) in each hole before you go to step 8.

8. Inspection of left hand and right ha nd stabilizer cutouts in tailboom 407-030- 801-101, /-105 and tailbooms field-modi fied by BHT drawing 407-799-046.

-NOTEThe factory has inspected edg es of cutouts on tailboom 407-030-801-107. Step 8 does not apply to tailboom 407-

030-801-107.
-NOTEThis inspection must also be completed on tailbooms modified and identified in accordance with BHT drawing

407-799-046.

a. Refer to Figure 4 and View H. Examin e the edges of the left and right stabilizer

cutouts made in the tailboom skins for cracks, burrs, nicks, and tool marks.

(1.) If there is a crack at the edge of the stabilizer cutou t, notify BHT Product Support Engineering with details.ASB 407-01-48 Page 13 of 32

(2.) If there is no crack, go to step b).

b. Rework any burrs, nicks, and tools mar ks not exceeding 0.020 inch (0.508 mm) deep using 400 grit minimum Aluminum Oxide sand paper (C-423).

c. Refinish all bare metal surfaces with a layer of primer (C-204).

d. If desired, paint the areas of the tailboom were the paint was removed per ASB

407-99-26 in order to match the aircraft paint scheme and colors.

PART II: Improved installation of st abilizer assembly (Refer to Technical Bulletin 407-01-33 for applicability).

a. Do the installation of the stabilizer assembly in accordance with Technical

Bulletin 407-01-33.

PART III: Identification of modified tailboom assemblies 407-030-801-101, /-105 and tailbooms field-modified by BHT drawing 407-799-046.

-NOTETailboom assemblies 407-030- 801-101, /-105 inspected

and modified in accordance with this bulletin are equivalent and interchangeable with tail boom assembly 407-030-801-

107. Tailboom 407-030- 801-107 does not need new

identification.

1. Identification of modi fied tailboom 407-030-801-101.

a. For tailboom 407-030-801-101 (see page 6, T able 1, Notes 1 and 2), mark the new identification plate 100-071-7 (Ref. Fi gure 5, item 17) by vibrating stylus

as follows:

(1.) Mark the first and second line of the new plate (17) with the existing part

number and serial number found on the original tailboom identification plate (18).

(2.) Mark on the third line “Modified to P/N 407-530-014-101”.

(3.) Mark on the fourth line the name of the repair facility that has done the

modification.ASB 407-01-48 Page 14 of 32

(4.) Mark on the fifth line, the date at which the modification was completed by the repair facility.

b. Form the plate (17) to match the ta ilboom contour for the location shown in Figure 5.

c. Locate the identification plate (17) on the top of t he tailboom skin as seen in Figure 5 and use a # 40 drill (0.098 in/2.48 mm) to make two holes.

d. Remove the plate (17) and deburr both si des of the two holes in the tailboom skin (7).

e. Coat faying surface of identification plate (17) with sealant (C-392) and install using two rivets (16).

f. Wipe excess sealant and make sure no vo id exists at the edges of the plate (17).

2. Identification of modi fied tailboom 407-030-801-105.

a. For tailboom 407-030-801-105 (see page 6, T able 1, Notes 1 and 2), mark the new identification plate 100-071-7 (Ref. Figure 5, Item 17) by vi brating stylus as follows;

(1.) Mark the first and second line of the new plate with the existing part

number and serial number found on the original tailboom identification plate.

(2.) Mark on the third line “Modified to P/N 407-530-014-103”.

(3.) Mark on the fourth line the name of the repair facility that has done the

modification.

(4.) Mark on the fifth line, the date at which the modification was completed by the repair facility.

b. Form the plate (17) to match the ta ilboom contour for the location shown in Figure 5.

c. Locate the identification plate (17) on the top of t he tailboom skin as seen in Figure 5 and use a # 40 drill (0.098 in/2.48 mm) to make two holes.

d. Remove the plate (17) and deburr both si des of the two holes in the tailboom skin (7).ASB 407-01-48 Page 15 of 32

e. Coat faying surface of identification plate (17) with sealant (C-392) and install using two rivets (16).

f. Wipe excess sealant and make sure no vo id exists at the edges of the plate (17).

PART IV: Assignment of retirement life and new recurring inspection requirements to tailboom assembly 40 7-030-801-107 and tailbooms 407-530-014- 101, /-103.

1. For tailbooms 407-530-014-101, /-103:

a. Create a new Historical Service Record sheet (HSR) for your modified tailboom

and indicate the time since new in the appropriate box.

b. Record date of the modifica tion completed on your tailboom.

-NOTEThe 5000 hours retirement life is assigned to the upper tailboom skin only, but for tracking purposes, is identified using the tailboom part num ber and serial number. When the tailboom assembly reaches a total of 5000 hours in service, a new skin cannot be installed and the tailboom

must be retired.

c. Assign a life of 5000 hours fr om the time at which the inspection/modification was completed and show in the appropriate box of the HSR, the total flight time

at which the tailboom must be retired.

d. Annotate the aircraft techni cal records to indicate compliance with this bulletin.

e. Install all the components that were removed in Step 2 of PART I and return the

tailboom to service.

f. Inspect your tailboom as instructed by Alert Service Bulletin 407-07-80.

g. When you have accumulated 5000 hours from the time of inspection/modification, re tire from service the tailboom 407-530-014-101 or

407-530-014-103 and install a serviceable unit.

2. For tailbooms 407-030-801-107:

a. Create a new Historical Service Reco rd sheet (HSR) for your BHT-original

tailboom and indicate the time since new in the appropriate box. C. C.ASB 407-01-48 Page 16 of 32

-NOTEThe 5000 hours retirement life is assigned to the upper tailboom skin only, but for tracking purposes, is identified using the tailboom part num ber and serial number. When the tailboom assembly reaches a total of 5000 hours in service, a new skin cannot be installed and the tailboom

must be retired.

b. Assign a life of 5000 hour s Since New in the appropriate box of the HSR, i.e. the total flight time at which the tailboom must be retired.

c. Annotate the aircraft techni cal records to indicate compliance with this bulletin.

d. Inspect your tailboom as instructed by Alert Service Bulletin 407-07-80.

e. When a Total Time Since New (T.T.S.N) of 5000 flight hours is reached, retire

from service the tailboom 407-030-801-107.

PART V: Maintenance and inspection of tailbooms 407-530-014-101, /-103

and tailboom 407-030-801-107.

1. Maintenance:

a. Maintain your tailboom in accordanc e with your 407 Maintenance Manual BHT407-MM-1 and the BHT corrosion control guide CSSD-PSE-87-001.

2. Inspection:

a. The inspection requirements as origina lly defined by this bulletin for your

tailboom 407-530-014-101/ -103 or tailboom 407- 030-801-107 are now cancelled and replaced by new inspecti on requirements defined under Alert

Service Bulletin 407-07-80. C. C. C.ASB 407-01-48 Page 17 of 32

Figure 1. Tailboom 407-030-801-101, /-105, inspection, modification and

identification of.ASB 407-01-48 Page 18 of 32

Figure 2. Tailboom 407-030-80 1-101, /-105, inspecti on and modification of (sheet 1 of 3)ASB 407-01-48 Page 19 of 32

Figure 2. Tailboom 407-030-80 1-101, /-105, inspecti on and modification of (sheet 2)ASB 407-01-48 Page 20 of 32

Figure 2. Tailboom 407-030-80 1-101, /-105, inspecti on and modification of (sheet 3) B. B.

B.ASB 407-01-48 Page 21 of 32

Figure 3. Tailboom 407-030-80 1-101, /-105, initial (v isual) inspection of.ASB 407-01-48 Page 22 of 32

Figure 4. Tailboom 407-030- 801-101, /-105, inspection (Eddy Current) and modification of (sheet 1 of 3) B.ASB 407-01-48 Page 23 of 32

Figure 4. Tailboom 407-030-801-101, /- 105, inspection (Eddy current) and modification of (sheet 2)ASB 407-01-48 Page 24 of 32

Figure 4. Tailboom 407-030-801-101, /- 105, inspection (Eddy current) and modification of (sheet 3) B.ASB 407-01-48 Page 25 of 32

Figure 5. Tailboom 407- 030-801-101, /-105, identification ofASB 407-01-48 Page 26 of 32ASB 407-01-48 Page 27 of 32



## ATTACHMENT “A”

Inspection of fastener holes on tailbooms P/N 407-030-801-101/-105 by Eddy Current method.

This inspection shall be c apable of detecting a 0.020 inch (0.508 mm) deep indication

on the surfaces indicated.

1.0 EQUIPMENT

NOTE

Eddy Current equipment shall be capable of detecting surface

and/or near surface discontinuities in electrically conductive materials, and shall be c apable of detecting impedance changes induced by variations in material properties as well as metallurgically and mechanica lly induced discontinuities. The equipment shall also contai n a means to display detected impedance changes.

NOTE

The probes shall be of the split shaft type (ref. Figure 1) and capable of inspecting hole diameters between 0.160/0.195inch (4.064/4.953 mm). Manual bolthole probes shall also have adjustable collar s to allow the operator to fix the depth of the probe inside the holes being inspected. The largest diameter of the collar s shall not exceed 0.750 inch (19.05 mm).

1.1 Hocking Phasec 2200 or Zetec Mi z 20 or equivalent Eddy Current Inspection equipment.

1.2 Eddy Current probes MBD2-1 0/12-1WL and MBD2-12/14-1WL or equivalent tuned to a frequency between 100 KHz – 1.0 MHz.

1.3 Aluminum crack calibration st andard number “BHTI EC-10-20” (ref. Figure 3). This standard may be obtained from the following sources:

EC/NDT LLC PH Tool

1020 S 344 th 10 Callowhill Road Suite 214 New Britain, PA 18901 Federal Way, WA 98003 Phone no. (888) 553-9245 Phone no. (877) 565-0797 Fax no. (215) 822-6799 Fax no. (253) 815-0827 E-mail sales@phtool.com
E-mail EC-NDT@worldnet.att.netASB 407-01-48 Page 28 of 32

2.0 PERSONNEL

2.1 All personnel performing Eddy Current inspection shall be qualified and certified to level II or level III requ irements established in AIA/NAS 410, SNT-TC-1A, or equivalent.

3.0 CALIBRATION

3.1 RIVET HOLES

3.1.1 Choose the eddy current probe (a s described in par.1.2) that best fits the rivet hole size being inspec ted. Adjust the probe coil depth

so that the coil is centered between the upper and lower surface of the standard. Lock the probe co llar in place to maintain the probe coil depth (ref. Figure 2).

3.1.2 Adjust the Eddy Current inst rument controls to reflect the following: Frequency: 500 KHz
V/H Gain: 15/10 OR a ratio of 1.5:1

Coarse Gain: 24 dB

Probe: Differential

Filters: Off

3.1.3 Place the probe into the appr opriate non-flawed hole of the standard and balance the probe. The balance point should be

located in the center of the screen.

3.1.4 Insert the probe into the appropriate hole of the standard containing the simulated 0.020” (0.508 mm) flaw and rotate the probe past the simulated crack. Adjust the instrument phase control so that the angle of the displayed signal response appears similar to that shown in Figure 4.

3.1.5 Adjust signal amplitude similar to that of Figure 4 (15 - 20% of the screen height).

NOTE 1: Automatic rotating bolthole guns and probes may be utilized for this inspection provided the intent of the re ferenced calibration and inspection procedures

are followed. Some variations to the signals s hown in Figure 4 may exist. Proper interpretation of signal response is the re sponsibility of the personnel performing the inspection.ASB 407-01-48 Page 29 of 32

4.0 PRE-INSPECTION

4.1 All applicable holes shall be inspect ed in the initial-reamed condition.

4.2 Verify the appropriate size probe for the holes being inspected. The probe diameter must be such that the coil is in contact with the inside

diameter surface of t he hole at all times.

4.3 All holes requiring Eddy Current in spection shall be free of edge burrs.

5.0 INSPECTION

5.1 RIVET HOLE INSPECTION

5.1.1 Measure through the hole from the surface of the support member

to the center of the tail boom ski n thickness using a depth gage. Use this measurement to adjust the probe collar so that the inspection coil will inspect the cent er thickness of the skin member only. 

# OR

Monitor the displayed Eddy Cu rrent signal response from the probe as it is pushed through the fastener hole. Lock the adjustable collar in place when the displayed Eddy Current signal

deflection is maximized between the upper and lower surfaces of the plate member requiring inspection.

5.1.2 Eddy Current inspect the inside bore of the rivet hole for a flaw signal response similar to that of the standard.

NOTE 2: Edge burrs around the holes must be removed from both inner and outer surfaces prior to Eddy Current inspecti on. Edge burrs will add unwanted electrical noise to the Eddy Current display and will complicate signal interpretation.

6.0 ACCEPT/REJECT CRITERIA

6.2 RIVET HOLES - Any indication t hat appears 0.020 inch (0.508 mm) in length or greater in the initial-reamed fastener hole size (ref. Table 2) is cause for rejection.ASB 407-01-48 Page 30 of 32

Probe

Adjustable

collar

Figure 2 Crack standard RIVET HOLE

CALIBRATION First, calibrate the bolthole probe to

the standard.

Second, move the adjustable collar so that the probe

coil will be at the same depth as the skin being inspected. Figure 1 

## SPLIT SHAFT BOLT HOLE PROBE

SPLIT SHAFT COIL

ADJUSTABLE

COLLARASB 407-01-48 Page 31 of 32

Figure 3 0.020 inch +/- 0.002 (0.508 mm +/- 0.050) length through wall EDM slot.

0.020 inch +/- 0.002 (0.508 mm +/- 0.050) length through wall

EDM slot. 

# BHTI EC-10-20 (manufacturer info here) 0.040 inch +/- 0.002 (1.016 mm +/- 0.050) length through wall EDM

slot



### .

0.172”
Dia.

holes 0.203”

Dia.

holes

S/N xxx

NOT TO SCALEASB 407-01-48 Page 32 of 32

0.020” inch (0.508 mm)

FLAW SIGNAL 

## BALANCE POINT

Figure 4 This display is typical of that produced by a differential Eddy Current probe. Approx.

15 – 20 %
Screen Height