NO. 

 

DATE 

PAGE 

 DATE 

 

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

407-07-80 

AUG 27, 2007 

1 of 18 

MODEL AFFECTED: 407

SUBJECT: TAILBOOM ASSEMBLY 407-030-801-107, AND 

407-530-014-101/-103, NEW INSPECTION 

REQUIREMENTS. 

HELICOPTERS AFFECTED: Model 407 helicopters serial number 53000 through 

53475 with subject tailboom installed.

 [Model 407 helicopters serial numbers 53476 and 

subsequent and serial numbers 53000 through 

53475 that have tailboom 407-030-801-201/-203/-

205 or later installed are not affected by the 

recurring inspections of this bulletin. 

COMPLIANCE: PART I Immediately after receipt of this bulletin. 

PART II Within 25 flight-hours or 30 days after 

accomplishment of PART I. 

PART III At the second flying day after 

accomplishment of Part II and before each first flight 

of the day thereafter. Compliance with this daily 

check can be accomplished by the pilot as part of 

his preflight check. 

PART IV Within 100 flight-hours after 

accomplishment of PART II and every 100 flighthours thereafter. 
ASB 407-07-80 

Page 2 of 18 

DESCRIPTION: 

CAUTION 

TAILBOOM ASSEMBLIES 407-030-801-107, 407-530-014-

101/-103 ARE AUTHORIZED FOR A MAXIMUM OF 5000 

HOURS IN SERVICE AFTER WHICH TIME THEY SHOULD 

BE RETIRED. REMOVAL AND/OR REPLACEMENT OF 

THE UPPER AND/OR LOWER SKINS IS NO LONGER 

AUTHORIZED ON THE TAILBOOM ASSEMBLIES 407-

030-801-107, 407-530-014-101/-103. 

Bell Helicopter received additional reports of cracked tailboom skins P/N 407-030-801-

157 affecting field-modified tailboom assemblies 407-530-014-101/-103 (Ref. ASB 

407-01-48) and original production tailboom assembly P/N 407-030-801-107. Each 

report indicated a crack seen above the left side upper stabilizer attachment support, 

at Station 98.89. Further investigation conduced by BHT revealed that other areas of 

the subject tailbooms do require additional attention. 

-NOTETailboom 407-030-801-101 and /-105 shall have had ASB 

407-01-48 Rev. “B” accomplished as of January 31, 2003 

therefore converted to tailboom 407-530-014-101/-103. 

-NOTETerminating action to this Alert Service Bulletin is 

replacement of the affected tailboom assembly 407-530-014-

101/-103 or 407-030-801-107 by tailboom 407-030-801-

201/-203/-205 or later. 

PART I of this Alert Service Bulletin requires identification of the affected tailboom. 

PART II of this bulletin gives instructions to remove the paint and the primer from the 

left side of the tailboom at two specific areas to allow detailed inspection. 

PART III of this bulletin introduces a daily visual check of the specific areas where 

paint and primer were removed under Part II. Compliance with this daily check can be 

accomplished by the pilot as part of his preflight check. 

PART IV changes the intervals of the scheduled inspection requirements described in 

Revision 23 of the Chapter 4 of the Maintenance Manual (BHT-407-MM-1, Table 4.2) 

to 100 Flight-hours and adds the new inspection requirements as defined by this 

bulletin. It also supersedes the inspection requirements as defined under PART V of 

Alert Service Bulletin 407-01-48 (Revision “B”). 
ASB 407-07-80 

Page 3 of 18 

APPROVAL: 

The engineering design aspects of this bulletin are TCCA approved. 

MANPOWER:

PART I: Approximately 0.5 man-hour is required to accomplish PART I of this bulletin. 

PART II: Approximately 1.5 man-hours are required to accomplish PART II of this 

bulletin. 

PART III: No more time is necessary if this check is being done as part of the Pilot’s 

Preflight check. 

PART IV: Approximately 2.5 man-hours are required to accomplish PART IV of this 

bulletin. 

NOTE: Man-hours are based on hands-on time, and may vary with personnel and 

facilities available. 

WARRANTY: 

Owners / Operators of the affected tailbooms that have completed Part 1, Part II (1.g.), 

Part III (1.d.) or Part IV (3.a.) of this bulletin and have found a crack in the detailed 

area listed in this bulletin may replace their tailboom at no cost providing you purchase 

a replacement tailboom part number 407-030-801-205 or later from a Bell approved 

supply source. 

Order a replacement tailboom through the Bell Spares Department or Bell approved 

source at full list price, and file a warranty claim in VISTA. Warranty administration will 

credit your account based on replacement part invoice cost. In addition, Bell Warranty 

will offer a maximum of $2,100.00 for labor to remove and replace the tailboom, shim 

and install the horizontal stabilizer, re-wire and paint the tail boom. An additional 

$400.00 maximum will be allowed for the cost of the paint. 

NOTE: Once you have replaced the tailboom, please remove the data plate from the 

unserviceable tailboom and notify Product Support Engineering Light Group of the 

serial number removed. Also notify your local CSR who will pick the data plate, and 

witness the destruction of the discrepant part. 
ASB 407-07-80 

Page 4 of 18 

MATERIAL: 

Required Material: 

None required. 

Consumable Material: 

For PART II: 

 Paint stripper (C-436) under MIL-R-81294A OR MIL-R-8633A. 

 Aluminum tape C-439, Aluminum Tape 425-2IN. 

 Clear polyurethane paint coating (C-245). Clear enamel coating in a spray can 

which is procured locally is an acceptable alternate to the clear polyurethane 

coating. 

 2 inch wide paint brush 

For PART III or PART IV: 

 Aircraft soap (C-318) under MIL-C-87936, as required. 

SPECIAL TOOLS: 

For PART II and PART IV: 10X Magnifying glass 

WEIGHT AND BALANCE: 

Not affected 

ELECTRICAL LOAD DATA: 

Not affected 

REFERENCES: 

ASB 407-01-48, Revision “C” 

ASB 407-07-77, dated March 28, 2007 

BHT-206-SRM-1 

BHT-407-MM-1, Rev 23, Maintenance Manual, Chapter 4 

BHT-407-MM-5, Rev 18, Maintenance Manual, Chapter 53 

Corrosion Control Guide, Chapter 10 

BHT-ALL-SPM, Rev. 2, dated 16 February, 2007 

PUBLICATIONS AFFECTED: 

BHT-407-MM-1, Rev 23, Maintenance Manual, Chapter 4 

ASB 407-01-48, Revision “B “ 
ASB 407-07-80 

Page 5 of 18 

ACCOMPLISHMENT INSTRUCTIONS: 

PART I VERIFICATION FOR AFFECTED TAILBOOM. 

1. Upon receipt of this bulletin, verify the helicopter technical records to 

determine if you have a tailboom 407-030-801-107, or 407-530-014-

101/103 installed. You can also physically confirm the tailboom part 

number by removing the aft driveshaft cover and looking at the 

identification plate located near Boom Station (BS) 129 as shown in Figure 

1. 

2. If identification as per Step 1 indicates that your tailboom is not affected by 

this bulletin, (meaning that you have a tailboom assembly 407-030-801-

201/-203 or /-205 (or later) installed on your helicopter), annotate the 

helicopter technical records to indicate that your tailboom is not affected by 

this bulletin. 

3. If identification as per Step 1 above indicates that you have one of the 

subject tailboom assembly, annotate the helicopter technical records to 

indicate the date and the helicopter total time at which PART I of this 

bulletin is complied with. 

4. Accomplish Part II within 25 hours of flight-time or 30 days following 

identification of affected tailboom under PART I of this bulletin.

PART II Preparation of tailboom assembly for Daily visual check (under 

 PART III) and for 100 Hour-10X magnifying glass inspection (under 

 Part IV). 

1. Remove the paint and primer from the left side only of your tailboom in the 

areas ( 1.5 inch X 2 inch( 38.1 mm X 50.8 mm)) shown under Figure 2 as 

follows; 

-CAUTIONOnce the paint and the primer is removed, and following 

initial 10X magnifying glass inspection, the unpainted 

surfaces must be protected from corrosion by application of 

a clear paint coating (see consumable material section for 

details). 

a) Use soap (C-318) prepared in accordance with manufacturer’s 

recommendations to clean all exhaust residues and dirt from the 

tailboom surfaces shown in Figure 2. 
ASB 407-07-80 

Page 6 of 18 

b) Refer to Figure 2 and use a felt marker to layout each area where the 

paint must be removed. 

c) Use Aluminum tape (C-439) to mask external area of each section 

identified in previous step. Make sure you put sufficient pressure over 

complete surfaces and edges of tape to get ultimate adhesion to the 

painted surfaces. 

-NOTEDo not remove sealant if present at edge of the upper 

stabilizer attachment support, at this time. This will be done 

later. 

-CAUTIONProtect other areas of the tailboom and the horizontal 

stabilizer from the paint stripper. 

d) Use a 2 inch wide (or smaller) paint brush and apply a thin coat of 

paint stripper (C-436) to each area. Wait a few minutes until all paint 

and primer is separating from the tailboom skin surface. Use clean 

cloth to wipe paint, primer and stripper residues. Re-apply new 

stripper as required. Repeat this process until the bare tailboom 

Aluminum skin is revealed (normally 2 or 3 times should suffice). 

e) Rinse reworked surfaces with soft water until all traces of paint 

stripper compound is removed. Wipe again the surfaces with dry 

cloth. If sealant is present at edge of stabilizer attachment support, 

remove it at this time with a plastic scrapper (or equivalent tool) but be 

careful not to damage the tailboom skin during removal process. 

f) Inspect both areas using a 10X magnifying glass. Pay close 

attention near edges of the stabilizer upper attachment support. 

g) If a crack is found, replace the tailboom before next flight and notify 

Bell Helicopter Product Support Engineering department. 

h) If another affected tailboom is installed on the helicopter, proceed 

with PART II or PART III of this bulletin, as applicable, prior to next 

flight. 

-NOTEClear enamel coating applied from a spray can is acceptable 

as an alternate to the clear polyurethane coating (C-245). 

i) If no crack is found, make sure both surfaces are dry and protect 

each reworked area with a thin coat of clear coating(C-245). Do not 

re-apply sealant if removed previously. 
ASB 407-07-80 

Page 7 of 18 

j) Let the clear coating dry and remove the Aluminum tape. 

PART III Daily visual check. 

-NOTEThis check requires no special tool but the paint and primer 

must be initially removed from the tailboom skin surface in 

accordance with PART II. Compliance with this Daily check 

can be accomplished by the pilot as part of his preflight 

check. 

 -NOTEDo not remove the clear paint coating to comply with this 

daily check. 

-NOTEIf your helicopter has not flown since accomplishment of 

PART II, start the daily checks at the second forthcoming 

day of flight. 

1. Before the first flight of the day, do a check for cracks in the areas where 

paint was removed on the left side of the tailboom assembly, as follows; 

a) Use a clean cloth moistened with aircraft soap (C-318) prepared in 

accordance with manufacturer’s recommendations, as required, to 

remove any exhaust residues or dirt from both areas to look at, as 

shown in Figure 2. 

b) Make sure that the tailboom skin is clean and that adequate lighting 

exists. Visually look at the two areas where original paint and primer 

was removed and protected with clear paint coating. Look for a crack 

at a distance not exceeding more than 12 inches (30.48 cm) from 

eyesight. 

c) Pay close attention near the edge of the stabilizer upper support. 

d) If a crack is found, replace the tailboom before next flight and notify 

Bell Helicopter Product Support Engineering department. 

e) If another affected tailboom is installed on the helicopter, proceed 

with PART II or PART III of this bulletin as applicable, prior to next 

flight. 

f) If no crack is found, the intent of PART III is complete. 
ASB 407-07-80 

Page 8 of 18 

2. Make an entry in the helicopter records to show that PART III of this 

bulletin is completed. 

3. Repeat steps 1 and 2 before each first flight of the day thereafter. 

4. Comply with subsequent 100 Hour inspection requirements described in 

PART IV when time is reached. 

PART IV: 100 Hour inspection requirements for tailbooms 407-530- 

 014-101 /-103 and tailboom 407-030-801-107. 

-NOTEPART IV changes the intervals of the scheduled inspection 

mandated by Revision 23 of the Chapter 4 of the 

Maintenance Manual (BHT-407-MM-1, Table 4.2) for all 

tailbooms listed in the subject block. It also supersedes the 

inspection requirements as defined under PART V of Alert 

Service Bulletin 407-01-48 (Revision “B”). 

1. Gain access to the areas to be inspected by removing both driveshaft covers 

and both gearbox fairings halves from your tailboom assembly. Refer to (BHT407-MM-5, Chapter 53). 

2. Clean the complete tailboom assembly (including the horizontal stabilizer, the 

two auxiliary finlets and the vertical fin) with aircraft soap (C-318) prepared in 

accordance with manufacturer’s recommendations to remove all traces of dirt, 

stains, exhaust residues and oil. 

3. Examine the complete tailboom assembly P/N 407-530-014-101/-103 or 

tailboom 407-030-801-107 every 100 Hours of operation for general condition, 

loose rivets, cracks or any other type of damage. Pay close attention to Area 

“A” indicated in Figure 3 for the left side of the tailboom. 

a) If a crack is found, replace the tailboom with a serviceable unit prior 

to next flight and notify Bell Helicopter Product Support Engineering 

department. 

b) If any other type of damage is found, refer to the negligible damage 

limits found in Chapter 53 of your maintenance manual or contact 

Product Support Engineering department for assistance. 

4. Inspect for loose rivets in region shown in Figure 3, Area “A” and especially in 

Details “E”, “F”, “G”, “H”, “I” and Views “D” and “J”. If a loose rivet or fastener 

is found, remove it per standard practices and inspect hole for cracks using a 
ASB 407-07-80 

Page 9 of 18 

10X magnifying glass. If no crack is found, install correct diameter rivet or 

fastener (Ref. BHT-206-SRM-1, section 3). 

5. If no loose rivets or fasteners are found loose, use a 10X magnifying glass and 

examine tailboom skin at edge of mating supports/brackets and around 

fasteners shown in Figure 3, Details “E”, “F”, “G”, “H”, “I” and View “D”. 

6. On left side of tailboom, use a 10X magnifying glass and examine tailboom skin 

at edge of mating supports/brackets and around fasteners shown in Figure 3 

Area “C” and View “J”. 

a) Pay close attention to both areas where clear paint coating exists. 

b) Make sure that the clear paint coating is in good condition and it does 

not obstruct inspection of the area (not opaque). If coating needs 

replacement, refer to PART II. 

c) Make sure the skin is not corroded. 

7. If any crack is found in Step 3 through Step 6 above, replace the tailboom with 

a serviceable unit before the next flight and notify Bell Helicopter Product 

Support Engineering department. If corrosion is found, refer to Chapter 53 of 

your maintenance manual for negligible damage limit or contact Product 

Support Engineering with details for assistance. 

8. If another tailboom affected by this bulletin is installed on the helicopter, 

proceed with PART II or PART III of this bulletin, as applicable, prior to next 

flight. 

9. If no crack is found, annotate the helicopter technical records to indicate that 

PART IV of this bulletin is complied with and return the tailboom to flight status. 

10. Carry subsequent Daily inspections as per PART III. 

11. Repeat this inspection every 100 flight-hours thereafter. 

 

AFFECTED TAILBOOMS, GENERAL MAINTENANCE 

1. Maintain your tailboom in accordance with your 407 Maintenance Manual 

BHT-407-MM-1 and the BHT corrosion control guide CSSD-PSE-87-001. 

2. Inspect your tailboom as per applicable requirements and recurring intervals 

as described herein. 
ASB 407-07-80 

Page 10 of 18 

Figure 1. Location of identification plate, tailbooms 407-530-014-101, 407-

530-014-103 or 407-030-801-107 
ASB 407-07-80 

Page 11 of 18 

Figure 2. Daily check, tailbooms 407-530-014-101, 407-530-014-103 or 407-

030-801-107 
ASB 407-07-80 

Page 12 of 18 

Figure 3. 100 Hour inspection of tailbooms 407-530-014-101, 407-530-014-103 

and 407-030-801-107 (Sheet 1 of 7). 
ASB 407-07-80 

Page 13 of 18 

Figure 3. 100 Hour inspection of tailbooms 407-530-014-101, 407-530-014-103 

and 407-030-801-107 (Sheet 2 of 7). 
ASB 407-07-80 

Page 14 of 18 

Figure 3. 100 Hour inspection of tailbooms 407-530-014-101, 407-530-014-103 

and 407-030-801-107 (Sheet 3 of 7). 
ASB 407-07-80 

Page 15 of 18 

Figure 3. 100 Hour inspection of tailbooms 407-530-014-101, 407-530-014-103 

 and 407-030-801-107 (Sheet 4 of 7).
ASB 407-07-80 

Page 16 of 18 

Figure 3. 100 Hours inspection of tailbooms 407-530-014-101, 407-530-014-

103 and 407-030-801-107 (Sheet 5 of 7). 
ASB 407-07-80 

Page 17 of 18 

Figure 3. 100 Hour inspection of tailbooms 407-530-014-101, 407-530-014-103 

and 407-030-801-107 (Sheet 6 of 7). 
ASB 407-07-80 

Page 18 of 18 

` 

Figure 3. 100 Hour inspection of tailbooms 407-530-014-101, 407-530-014-103 

and 407-030-801-107 (Sheet 7 of 7).