ASB 407-11-95C Page 1 of 38

ECCN EAR99 ALERT SERVICE BULLETIN 407-11-95 11 July 2011 Revision C, 20 April 2012

MODEL AFFECTED: 407

SUBJECT: UPPER LEFT LONGERON (CHANNEL) P/N 206-

031-314-037/ -177 AND SPARE ASSEMBLY P/N 206-031-314-219B, INSPECTION OF.

HELICOPTERS AFFECTED: Serial numbers 53000 through 53900, 53911 through 54061 and 54300 with cumulative flight

time of 1200 hours or more.

[Serial numbers 54062 through 54299 and 54301 and subsequent with improved longeron assembly

P/N 206-031-314-237B installed at the factory and affected helicopters listed above having longeron 206-031-314-237B procured as a replacement unit

and installed are not affe cted by this bulletin.]

COMPLIANCE: PART I: For helicopters delivered from factory with subject channel or having a replacement assembly

P/N 206-031-314-219B inst alled exceeding 1200 flight-hours in service, within 50 flight-hours after publication of this bulletin but no later than August

31 st , 2011.

PART II: Within 10 flight-hours after completion of PART I, and every 50 flight -hours thereafter or every 150 flight-hours thereafter when PART III is a. Every 50 flight-hours when Part IV is accomplished.

PART III: At customer’s option.

PART IV: Before next flight when a longeron is found

cracked.

PART V: At customer’s option.ASB 407-11-95C Page 2 of 38

ECCN EAR99 DESCRIPTION:

Bell Helicopter has received reports of upper L/H longeron (c hannel) cracking in

service. The cracks were located in the sa me region of the channel near frame at Fuselage Station (FS) 217.84. The chan nel P/N 206-031-314-037 was installed at factory on S/N 53001 through 53034. The channe l P/N 206-031-314-177 was installed at factory on S/N 53035 through 53900, 53911 through 54061 and on 54300. The longeron assembly P/N 206-031- 314-219B was sold as a spare unit. PART I of this bulletin mandates a one-time inspection of the aft fuselage top skin P/N 206-033-003- 161, /-167 on helicopters exce eding 1200 hours of flight time. PART II provides instructions for inspection of specific areas of the aft fuselage. PART III of this bulletin

introduces the addition of thr ee external strap doublers to extend the intervals of the recurring inspection described in PART II. PART IV of this bulletin provides a repair procedure for a cracked longeron and mandates the installation of the external straps

as defined under PART III. PART V describes the installati on of improved longeron assembly P/N 206-031-314-237 B and the 3 external CRES strap doublers under PART III of this bulletin as a terminating ac tion to the inspections defined in this bulletin. Revision A includes longeron asse mbly P/N 206-031-314-219B in the title, changes the compliance time of PART I fr om 25 hours to 50 hours, describes the effectivity of channels P/N 206-031-314-037/, -177 as delivered from the factory, describes the longeron assembly P/N 206-031-314-219B as being delivered as a spare longeron, lists additional rivets as part of kit CA-407-11-95-1 and emphasizes the requirement of the installation of t he 3 external strap doublers, if PART V is accomplished and provides the amount of estimated m an-hours to accomplish PART

V. Revision B makes reference to Tec hnical Bulletin 407-12 -96 as the approved instructions to comply with PART V of this bulletin and re -adjusts the estimated manhours required for accomplishment of PART V in order to match those of TB 407-12-

96 . Revision C modifies the warranty statement.

APPROVAL:

The engineering design aspects of this bulletin are Transpo rt 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.comASB 407-11-95C Page 3 of 38

ECCN EAR99 MANPOWER:

Approximately 1.0 man-hour is required to complete PART I of this bulletin. Approximately 3.0 man-hours ar e required to complete PART II of this bulletin. Approximately 6.0 man-hours are required to complete PART III of this bulletin. Approximately 16.0 man-hours ar e required to complete PART IV of this bulletin. Approximately 35.0 man-hours are required to complete PART V of this bulletin. Manhours are based on hands-on time, and ma y vary with personnel and facilities

available.

WARRANTY:

Owners / Operators of Bell Helicopters who comp ly with the instructions in this bulletin will be eligible to receive a credit for the replacement parts outlined in the material section of this bulletin only when a cracked longeron is found.

To receive this credit:

 Comply with the instructions contained in PART IV of this bulletin.

 Purchase replacement parts as requir ed in the materials section of this bulletin from a Bell approved source.

 Submit an MMIR to the Bell Warranty Department.

Customers who fail to comply with the instructi ons in this bulletin within the applicable hours or calendar date in the compliance section of this bulletin are not eligible for the special warranty credit listed above. There is no labor asso ciated with this bulletin.

Warranty compensation as stated above is no longer applicable for affected longerons

found with a crack after June 30 th 2012.

MATERIAL:

Required Material: The following material is required for the ac complishment of this bulletin and may be obtained through your Bell Helico pter Textron Supply Center.

For the accomplishment of PART III of this bu lletin, order installation kit # CA-407-11-

95-1

Part Number Nomenclature Qty PART 407-530-020-115 Strap doubl er 1 (Note 1) III 407-530-020-117 Strap doubl er 1 (Note 1) III 407-530-020-119 Strap doubl er 1 (Note 1) IIIASB 407-11-95C Page 4 of 38

ECCN EAR99 NAS9307M-4-04 Rivet 30 (Note 2) III NAS9307M-4-05 Rivet 10(Note 2) III NAS9307M-4-06 Rivet 10(Note 2) III NAS9307M-4-07 Rivet 10(Note 2) III NAS9307M-5-05 Rivet 20 (Note 2) III NAS9307M-5-06 Rivet 10 (Note 2) III NAS9307M-5-07 Rivet 10(Note 2) III MS20470AD4-4 Rivet 20 (Note 2) III MS20470AD4-5 Rivet 20 (Note 2) III MS20470AD5-7 Rivet 5(Note 2) III

For the accomplishment of PART IV of this bulletin, order installation kit # CA-407-11-

95-2

Part Number Nomenclature Qty PART 407-530-020-121 Angle 1 (Note 1) IV 206-032-307-023S Clip 1 (Note 1) IV

407-530-020-123 Radius bl ock 2 (Note 1) IV

407-530-020-125 Radius bl ock 1 (Note 1) IV NAS9307M-5-02 Rivet 30(Note 2) IV NAS9307M-5-03 Rivet 30(Note 2) IV NAS9307M-5-05 Rivet 30(Note 2) IV NAS9307M-5-07 Rivet 30(Note 2) IV NAS9310M-5-03 Rivet 30(Note 2) IV NAS9310M-5-04 Rivet 30(Note 2) IV 100-140-2 Identification plate 1 IV

NOTE 1: Parts can be locally fabricated. See Figure 3 and Figure 4 for details.

NOTE 2: Length of rivets may vary from one he licopter to another. The correct length

of rivets must be determined at installation.

Consumable Material: The following material is required to a ccomplish this bulletin, but may not require ordering, depending on the operator ’s consumable material stock levels. This material may be obtained through your Bell He licopter Textron Supply Center.

Part Number Nomenclature Qty Reference

AMS-S-8802 PT Sealant 1 C-308 MIL-PRF-23377, TY I Epoxy Polyami de Primer (see Note 1) 1 C-204 TT-I735 ISOPROPYL Isopropyl Alc ohol (See Note 2) 1 C-385

MIL-C-81706 1 QT Chem. Film Alodine 1200 1 C-100

299-947-

100TY2CL2G50 Adhesive 1 C-317ASB 407-11-95C Page 5 of 38

ECCN EAR99 NOTE 1: Primer MIL-P-85582 can be used as a substitute.

NOTE 2: Toluene ( C-306 ) or Ethyl Alcohol (C 339) can be used as substitute.

SPECIAL TOOLS:

None required.

WEIGHT AND BALANCE:

Accomplishment of PART III will have the fo llowing effect on the Weight & Balance

data sheet: Longitudinal Lateral* Weight Arm Moment Arm Moment

+0.3 Lbs 218.0 in. +65 in-Lbs -5.0 in. -2 in-Lbs

(+0.1 kg) (5537 mm) (+7. 5 kg x mm/100) (-127 mm) (-0.2 kg x mm/100)

Accomplishment of PART IV will have the following effect on the Weight & Balance

data sheet: Longitudinal Lateral* Weight Arm Moment Arm Moment

+0.7 Lbs 217.0 in. +152 in-Lbs -6.0 in. -4 in-Lbs

(+0.3 kg) (5512 mm) (+17.5 kg x mm/100) (-152 mm) (-0.5 kg x mm/100)

* In lateral calculations, - is left and + is right.

NOTE: This is the Delta Weight effect of this ki t. It includes the we ight & effect of the

items removed when this kit is installed.

ELECTRICAL LOAD DATA:

Not affected.

REFERENCES:

BHT-407-IPB Illustrated Part s Breakdown, Chapter 53

. BHT-407-MM Maintenance Manual, Chapter 5

BHT-206-SRM-1 Structural Repair Manual

TB 407-07-78 , Aft Fuselage Bulkhead 407-030- 027-101 at FS 231.4, Introduction of.

TB 407-12-96 , Aft Fuselage Upper Left Longeron Assembly P/N 206-031-314-237B,

Introduction of.ASB 407-11-95C Page 6 of 38

ECCN EAR99 PUBLICATIONS AFFECTED:

BHT-407-MM Maintenance Manual, Chapter 4 and Chapter 5

. BHT-407-IPB Illustrated Part s Breakdown, Chapter 53

.

ACCOMPLISHMENT INSTRUCTIONS:

PART I: One Time Inspection of the Aft Fuselage Top Skin

-NOTEThis inspection applies to affected helicopters having channel P/N 206-031-314-037, /-177 in stalled by the factory or replacement longeron a ssembly P/N 206-031-314-219B installed as a spare unit, all above having accumulated 1200 flight-hours or more.

1. Gain access to the aft fuselage upper ski n (5, Figure 1) by removing the oil cooler blower fairing (7).

2. Remove tailboom access panel (1, Figure 2).

3. Clean upper skin (5, Figure 1) and use a 10X magnifying glass as indicated in View A, Notes 1 and 2, to inspect the upper and lower surfaces of the upper skin for

cracks in the area shown.

a. If a crack is found, accomplis h PART II before next flight.

4. If no crack is found in the aft fuselage top skin (5), reinstall the oil cooler blower fairing (7) and the tailboom access panel (1, Figure 2).

5. Make an entry in helicopter historical service records indicating compliance with

PART I of this bulletin.

6. Accomplish PART II within the next 10 flight-hours.ASB 407-11-95C Page 7 of 38

ECCN EAR99 PART II: Inspection of the Upper Left Longeron Assembly

-NOTEThis inspection applies to affected helicopters having channel P/N 206-031-314-037, /-177 in stalled by the factory or replacement longeron a ssembly P/N 206-031-314-219B installed as a spare unit, all above having accumulated 1200 flight-hours or more. It also applies to units that have been repaired in accordance with PART IV of this bulletin.

1. Remove the oil cooler blower fairing (7, Figure 1), the tailboom access panel (1, Figure 2), and the air dam cover (2) in accordance with BHT-407-MM-5

, Chapter

53

.

-NOTESealant providing fume tightne ss of the frame at Station 217.84, if not removed, may hide a crack in the longeron.

2. Inspect aft fuselage upper skin (5, Figur e 1) as defined under PART I. If the top skin is not cracked, go to step 3 below. If inspection of the skin (5) as per PART I
revealed a cracked, remo ve skin (5) as follows:

a. Record fasteners type, size and location and remove the skin (5).

b. Drill the two remaining rivets maintaini ng the splice (8, Figure 2, View C) in place against frame (4 ) at STA 217.84 and remove the splice (8).

c. Remove all traces of sealant on the upper flange of the lon geron (3) at station 217.84 and inspect for a crack. Pay attent ion to the transition area (narrowing section) of the upper flange (Sta. 217.84). If the longeron (3) is found cracked, go to step 6.

3. Remove all traces of sealant covering t he longeron (3, View B) on either side of the frame (4) at STA. 217.84 as indicated in Area 1 and Area 2. Clean sealant using a plastic scraper.

4. Make sure the area is clean and visually ins pect all visible sections of the upper left longeron (3) between aft fuselage frame (7 ) at STA 231.472 and frame (6) at STA 204.92 for general condition, corrosion and crack. Pay particular attention to Area

1 and Area 2.ASB 407-11-95C Page 8 of 38

ECCN EAR99 5. If corrosion is found, submit details to Product Support Engineering for evaluation and possible repair.

6. If the longeron (3) is found cracked, it may be r eplaced using P/N 206-031-314- 237B or repaired in accordance with PART IV of this bulletin. Installation of a new longeron assembly P/ N 206-031-314-237B done in conjunction with accomplishment of PART III of this bulletin (i nstallation of 3 exte rnal strap doublers) is considered by Bell Helicopter Textron as a terminating action to this bulletin.

-NOTEInstallation of the strap dou blers (5, 6 and 7, Figure 3, Detail B) is optional when lo ngeron (3, Figure 2) with top skin (5, Figure 1) is free of defects and do not carry any type of repair. This option will extend the recurring 50 flight-hours inspection intervals to 150 flight-hours inspection intervals.

-NOTEInstallation of strap doubler s (24, 25, and 26, Figure 4, View M) is mandatory as part of the airworthiness limited repair of a cracked longeron (13) as described in PART IV of this bulletin and/or as part of the installation of the new longeron assembly P/N 20 6-031-314-237B as described

in PART V of this bulletin.

7. If the external strap doublers (5, 6 and 7, Figure 3, Detail B) are installed, clean each strap doubler (5, 6 and 7) and inspect using a 10X pow er magnifying glass as shown in Figure 4, View M.

8. If the longeron (3, Figure 4, View L) has been repaired in accordance with PART IV of this bulletin, expand the inspection as follows;

a. Visually inspect the complete longer on (3), the repair angle (17), and the clips (14, 18).

b. If damage is found in any of the parts listed above, contact Product Support Engineering with details.ASB 407-11-95C Page 9 of 38

ECCN EAR99 9. If no defects are found, rein stall a new upper skin (5, Fi gure 1) if applicable, the splice (8, Figure 2, View C) and the air dam cover (2 ) per Chapter 53 of the Maintenance Manual. Re-app ly sealant where needed exc ept in Area 1 and Area 2 as shown where further recurring inspection will have to be performed.

10. Install the tailboom access panel (1) and the oil cooler bl ower fairing (7, Figure 1).

11. Make an entry in helicopter historical service records indicating compliance with

PART II of this bulletin.

-NOTETo benefit the replacement of the 50-hour intervals by 150-hour intervals, the longer on (3, Figure 2) and the top skin (5, Figure 1) must be free of defects and shall not carry any type of repair.

12. Perform the inspection described above every 50 flight-hours or every 150 flighthours thereafter as applicable

PART III: Installation of the External Strap Doublers

-NOTEInstallation of the strap doublers (5, 6 and 7, Figure 3, Detail B) is optional when longeron (3 , Figure 2) with top skin (5, Figure 1) is free of defects and do not carry any type of repair. This option will extend the recurring 50 flight-hours inspection intervals to 150 fli ght-hours inspection intervals.

Installation of strap doubler s (24, 25, and 26, Figure 4, View M) is mandatory as part of the airworthiness limited repair of a cracked longeron (13) as described in PART IV of this bulletin and/or as part of the installation of the new longeron assembly 206-031-314 -237B as described in

PART V of this bulletin.

1. Remove the oil cooler blower fairing (7, Figure 1), the tailboom access panel (1, Figure 2) and the air dam cover (2) in accordance with BHT-407-MM-5

, Chapter

53

.ASB 407-11-95C Page 10 of 38

ECCN EAR99 2. Perform the inspection on the aft fu selage upper skin (5, Figure 1) and the longeron (3, Figure 2) as per PART II of this bulletin.

3. If no defect is found in the upper skin (5, Figure 1) or in the longeron (3, Figure 2), identify and remove existing rivets (8, 10, and 11, Figure 3, View A and Detail B) where the new external strap doubler s (5, 6 and 7) will be installed.

4. Remove and clean any se alant on the lower side of upper flange of longeron (13) at the area where rivets (8, 10, and 11) we re removed in step 3, using a plastic

scraper.

-NOTEStrap doublers (5, 6 and 7) can be locally fabricated. Refer to Figure 3 for details.

5. Locate the strap doublers (5, 6 and 7, View A and Detail B) on top of fuselage skin (2) as shown with respect to FS 217.84. If the longest strap (5) interferes with cowl retainer filler (14, Detail C), trim affected parts as follows:

a. If the strap (5) requires trimming, remove the strap (5) and trim as shown Detail C and Section D-D, ensuring a minimum edge distance of 2D is maintained.

b. If the cowling retainer f iller (14) requires additional trimming, remove existing rivets securing the cowling rail (4) and the filler (14) on top of the aft fuselage skin (3) and skin panel (2). Tr im filler (14) as shown.

c. Coat faying surfaces of rail (4) and filler (14) with s ealant ( C-308 ) before reinstallation of the rail (4) back on t he aft fuselage using fasteners wet with sealant ( C-308 ).

d. Coat all visible portions of the new ri vets you have just installed inside of aft fuselage structure with sealant ( C- 308 ), ensuring not to apply sealant on

surfaces between affected rivets. Do not apply sealant ( C-308 ) in the Area 1 and Area 2 (Figure 2, View B) to be inspected later.

6. With the strap doublers (5, 6 and 7, Figure 3) in their proper position, backdrill all existing rivet holes from the longeron (13) through all the strap doublers (5, 6 and 7). Ensure a minimum of 2D edge distance is maintained.

7. Remove the strap doubler s (5, 6 and 7) from their lo cation and deburr all holes. Clean all surfaces with Isopropyl Alcohol ( C-385 ).ASB 407-11-95C Page 11 of 38

ECCN EAR99 8. Apply sealant ( C-308 ) to faying surfaces of doublers (5, 6 and 7, View A) and reinstall on fuselage using applicable rivets wet with sealant ( C-308 ).

9. Touch up all bare Aluminum Alloy metal surfaces using Chem. film material ( C100 ).

10. Coat all visible portions of the new rivets (Detail C, Section D- D) inside aft fuselage structure with sealant ( C-308 ), ensuring not to apply sealant on surfaces between affected rivets. Do not apply sealant ( C-308 ) in the Area 1 and Area 2 (Figure 2, View B) to be inspected later.

11. Reinstall air dam cover (2, Figure 2) per Chapter 53 of the Maintenance Manual. Re-apply sealant where needed except in Area 1 and Area 2 where further recurring inspection will have to be perform ed. Install the tailboom access panel (1) and the oil cooler blower fairing (7, Figure 1).

12. Refinish exterior surfaces of the helicopt er as required with prim er ( C-204 ) and final paint coatings in accor dance with the Standard Practice s Manual BHT-ALL-SPM

.

13. Make an entry in helicopter historical service records indicating compliance with

PART III of this bulletin. Indicate also that the recurring inspection described in PART II at every 50 flight-hours intervals is extended to 150 flight-hours intervals if

this installation is not to coincide with PART IV.

14. Repeat the inspection of the aft fuselage area as described un der PART II at every 150 flight-hours intervals.

PART IV: Airworthiness Limited Repair of a Cracked Longeron

-NOTEInstallation of the three ex ternal strap doublers (5, 6 and 7, Figure 3) as defined under PART III is mandatory during the repair of a cracked longeron.

1. Remove the tailboom assembly (21, Fi gure 4) from the aft fuselage section in

accordance with Chapter 53 of the 407 Maintenance Ma nual and install on appropriate support device.

2. Draw two parallel extension lines (see Section C-C) from the shear clip (10) forward flange onto the aft face of frame (4) located at STA 217.84 using a felt pen.ASB 407-11-95C Page 12 of 38

ECCN EAR99 3. Drill the four existing solid rivets (11) securing the inboard clip (10) to the bulkhead frame (4) and the longeron (3 ) at FS 217. 84. Remove i nboard clip (10) and retain

for use later as a workaid.

4. Clean any remaining sealant residue between edge of frame (4) and longeron (3) and verify that enough space exist to slide t he repair angle (17) in place. If additional space is needed, proceed as follows:

a. Use a piece of emery cloth inserted between the edge of the frame (4) and the inner face of longeron (3). Work emer y strip back and forth until 0.050 inch (1.27 mm) gap clearance is obtained. Do not exceed 0.050 inch (1.27 mm)

maximum material removal.

b. Treat bare metal surfaces with alodine ( C-100 ) and primer( C-204 ).

5. If the crack in the longeron (3) (View D and View E) has migrated through the complete unit (complete failure), omit step 6 and go to step 7.

6. If the crack has not migrated through th e complete longeron (3) (not a complete failure), stop drill the cra ck in accordance with the proc edure 3-2-1C described in the Structural Repair Manual;

-NOTEStop-drilling is not re quired if the crack stops at any of the

rivet holes in Zone “B” or Zone “C”.

Omit stop-drilling the crack if located under the footprint of the clip (14).

a. Stop-drilling must be done only when the crack is in any part of Zone “A” away from the footprint of outboard clip (14).

b. Deburr both sides of the stop-drilled hole.

7. Sand the crack seen on inboard face of t he longeron (3) in a fore and aft direction to remove any possible ridges along the cr ack that may interfere with the repair angle (17). Use Aluminum Oxide sandpap er ( C-423 ), 280 gr it or finer.ASB 407-11-95C Page 13 of 38

ECCN EAR99-NOTERepair angle (17) with radius blocks (19 and 22) can be purchased from Bell Helicopter Textron (BHT) or locally fabricated. Refer to Figure 4 fo r details if parts are to be fabricated locally.

8. Prepare the repair angl e (17) as follows;

a. Mark the rivets layout (View F) and dr ill pilot holes in repai r angle (17), using #

40 drill bit.

b. Fit the repair angle (17) in place against inner face of longeron (3) and its lower flange.

c. The longeron (3) and repair angle (17) lower flanges have different contours; therefore, make sure the poi nt of contact (pivot point) of the repair angle (17) is

in line with the bulkhead at STA 217. 84 as indicated in View F, Note 9.

d. Maintain at each extremity of th e repair angle (17), equal gaps between the lower flange of the repair angl e (17) and the lower flange of the longeron (3).

9. Secure the angle (17) tight against the longeron (3) with clamps.

10. Position the clip (10) y ou have retained in step 3 against aft face of frame (4). Clip (10) should be located exactly between ex tension lines made earlier (see section C-C) before being secured to t he aft face of frame (4);

a. Mark the contour of the aft vertical flange of clip (10), onto vertical face of repair angle (17).

b. Using the existing two rivet holes in aft vertical flange of clip (10), drill two new 5/32 holes in the repair angl e using #20 drill bit. These two new holes in repair angle (17) should be in line with existing holes in longeron (3) and outboard clip (14).

c. Remove clip (10) and discard.

11. Place the new undrilled c lip (18) in place between the markings made in step 10a above on vertical face of repair angle (17).ASB 407-11-95C Page 14 of 38

ECCN EAR99 a. Secure clip (18) to re pair angle (17) then mark onto the clip (18) the two holes made in repair angle (17) in step 10b.

b. Transfer the two new 5/32 holes to the undrilled flange of c lip (18) from the frame (4).

c. Remove clip (18) and drill two remainin g new 5/32 diameter holes in flange of clip using marks made in step above.

12. Determine the exact location and orientation of the crack (see View E). If the crack is in Zone “A” only, go directly to step 14.

13. If the crack is passing through Zone “A” and also through Zone “B” and/or Zone “C” proceed as follows:

a. Position and secure the r adius block (22) agai nst outboard face of clip (14, View J and Section K-K).

b. Transfer existing 5/32 diameter ri vet holes common to repair angle (17), longeron (3) and flange of clip (14) to the ra dius block (22), using a # 20 drill bit.

c. Remove the radius block ( 22) and the repair angle (17).

d. Prepare the mating surfaces of clip ( 14) and radius block (22) for bonding by removing the surface finish, using Alum inum Oxide sanding paper ( C-423 ).

e. Increase size of both rivets holes in th e existing longeron (3) and the clip (14) to .250 inches (6.35 mm) diameter.

f. Reinstall in position the repair angl e (17) and the radius block (22).

CAUTION

Protect the inner skin of side skin panel (by inserting a piece of flat CRES material between the inboard face of the skin panel (core) and t he outboard face of the longeron.

-NOTEThere are no rivets installed or holes drilled in the lower flange of neither the repair angl e (17) nor the longeron (3).ASB 407-11-95C Page 15 of 38

ECCN EAR99 14. Transfer remaining pilot hol es from the repair angle (17) to the longeron (3) using #

40 drill bit. Install Clecos as you progress.

15. When finished, enlarge diameter of eac h hole in angle (17) and longeron using #20

drill bit.

16. Drill oversize hole using a # 16 drill bit through the hole common to the new clip (18), the longeron (3), the clip (14) and the radius bl ock (22) (if being used).

17. Remove the clip (18), the repair angle ( 17) and the radius block (22) if used and

deburr all holes. Deburr all new holes in longeron (3) and all other parts fixed on

the airframe.

18. Inspect holes in clip (18). If installati on of rivets interferes with clip bend radius, prepare radius block (19) as follows;

a. Match radius block (19) with applicable flange where it will be needed and

transfer rivets holes in radius block (19) to match holes in clip (18).

b. Deburr all holes in radius block (19).

19. Coat faying surfaces the repair angle ( 17) with sealant ( C-308 ) before securing in place against longeron (3) with Clecos;

a. Make sure there is enough quantity of sealant ( C-308 ) on the lower flange of the repair angle (17) to fill the gaps at each extremity (View F).

b. Clean excess sealant ( C-308 ) squeeze out.

20. Coat faying surfaces of clip (18) ( and applicable radius blo ck (19) if used) with sealant ( C-308 ) and secure to frame (4) us ing Clecos. Do not secure other flange of clip (18) to repair angl e (17) at this time.

21. If the radius block (22) is to be install ed, coat the mating surfaces of radius block (22, section K-K) and out board clip (14) with structur al adhesive ( C-317 ) before securing the radius block (22) in place us ing Clecos through inner clip (18), repair angle (17), longeron (3), the out er clip (14) and finally the radius block (22).

22. Install all applicable rivets (View F) wet with sealant ( C-308 ).

23. Make sure no sealant ( C-308 ) is re-appl ied to longeron and fram e (3 and 4, Section H-H and K-K) as shown.ASB 407-11-95C Page 16 of 38

ECCN EAR99 24. Mark identification plate (23, Vi ew F) with the following information:

a. If mating holes in longeron (3) and clip (14) were drilled to .176/.180 inch (4.47/4.57 mm)(using #16 drill bit), meaning that the crack is in Zone “A” only, mark plate (23) using part number # 407-530-020-103 to re-identify longeron.

b. If mating holes in longeron (3) and clip (14) were drilled to .250 inch (6.35 mm) diameter, meaning that the crack affect ed Zone “A” and Zone “B” and/or “C”, mark plate (23) with part number 407-530-020-105 to re-identify longeron.

c. Mark the serial number of the helicopter on the lower window of the identification plate (23).

d. Clean area of the longeron (3) where the plate (23) will be installed using Isopropyl Alcohol ( C- 385 ) and let dry.

e. Coat faying surface of identificati on plate (23) with st ructural adhesive and

install in area as shown on the i nner face of the longeron (3).

25. If not already done, install the 3 external strap doublers (5 , 6, and 7, Figure 3) in

accordance with PART III of this bulletin.

26. Reinstall air dam cover (2, Figure 2) per Chapter 53 of the Maintenance Manual. Re-apply sealant where needed except in Area 1 and Area 2 where further recurring inspection will have to be perform ed. Install the tailboom access panel (1) and the oil cooler blower fairing (7, Figure 1).

27. Reinstall the tailboom assembly (21, Figure 4).

28. Make an entry in helicopter historical service records indicating compliance with PART IV of this bulletin. Where applicable , indicate also that the recurring 150 flight-hours inspection intervals of PART II are now being reduced to 50 flight-hours

intervals.

29. Repeat the inspection of the aft fuse lage area as described under PART II following every 50 flight-hours.

PART V: Terminating Action to Recurring Inspections Defined in this Bulletin

-NOTETerminating action to the present Alert Service Bulletin will

occur with the installation of a new longeron assembly P/NASB 407-11-95C Page 17 of 38

ECCN EAR99 206-031-314-237B combined with t he installation of the 3 external CRES strap doublers defined in PART III of this bulletin. The airworthiness insp ection limitations defined in this bulletin will no longer appl y. The new lo ngeron will be subjected to the regular ins pections defined in Chapter 5

.

1. Gain access to the existing upper left longeron assembly and replace using

instructions found in Tec hnical Bulletin 407-12-96.

2. Install concurrently the 3 external CRE S strap doublers using in structions in PART

III of this bulletin.

3. Inspect the longeron assembly and the 3 external str ap doublers under the scheduled inspections defined in Chapter 5 of the Maintenance Manual.ASB 407-11-95C Page 18 of 38

ECCN EAR99 Figure 1 - Inspection of Aft Fuselage Upper SkinASB 407-11-95C Page 19 of 38

ECCN EAR99 Figure 2 - Inspection of L/H Uppe r Longeron Channel (sheet 1 of 3)ASB 407-11-95C Page 20 of 38

ECCN EAR99 Figure 2– Inspection of L/H Upper Longeron Channel (sheet 2)ASB 407-11-95C Page 21 of 38

ECCN EAR99 Figure 2– Inspection of L/H Upper Longeron Channel (sheet 3)ASB 407-11-95C Page 22 of 38

ECCN EAR99 Figure 3– Installation of Strap Doublers (sheet 1 of 3)ASB 407-11-95C Page 23 of 38

ECCN EAR99 Figure 3– Installation of Strap Doublers (sheet 2)ASB 407-11-95C Page 24 of 38

ECCN EAR99 Figure 3– Installation of Strap Doublers (sheet 3)ASB 407-11-95C Page 25 of 38

ECCN EAR99 Figure 4- Repair of Cracked Longeron (sheet 1 of 14)ASB 407-11-95C Page 26 of 38

ECCN EAR99 Figure 4- Repair of Cr acked Longeron (sheet 2)ASB 407-11-95CPage 27 of 38ECCN EAR99Figure 4- Repair of Cracked Longeron (sheet 3)ASB 407-11-95C Page 28 of 38

ECCN EAR99 Figure 4- Repair of Cr acked Longeron (sheet 4)ASB 407-11-95CPage 29 of 38ECCN EAR99Figure 4- Repair of Cracked Longeron (sheet 5)ASB 407-11-95C Page 30 of 38

ECCN EAR99 Figure 4- Repair of Cr acked Longeron (sheet 6)ASB 407-11-95C Page 31 of 38

ECCN EAR99 Figure 4- Repair of Cr acked Longeron (sheet 7)ASB 407-11-95C Page 32 of 38

ECCN EAR99 Figure 4- Repair of Cr acked Longeron (sheet 8)ASB 407-11-95C Page 33 of 38

ECCN EAR99 Figure 4- Repair of Cr acked Longeron (sheet 9)ASB 407-11-95C Page 34 of 38

ECCN EAR99 Figure 4- Repair of Cr acked Longeron (sheet 10)ASB 407-11-95CPage 35 of 38ECCN EAR99Figure 4- Repair of Cracked Longeron (sheet 11)ASB 407-11-95C Page 36 of 38

ECCN EAR99 Legend

Figure 4- Repair of Cr acked Longeron (sheet 12)ASB 407-11-95C Page 37 of 38

ECCN EAR99 Figure 4- Repair of Cr acked Longeron (sheet 13)ASB 407-11-95C Page 38 of 38

ECCN EAR99 Figure 4- Repair of Cr acked Longeron (sheet 14)