ASB EC135-53A-029

Revision 0, 2013-11-19 PAGE 1 of 7

Valid for Version(s): T1, T2, T2+, P1, P2, P2+

635 T1, 635 T2+, 635 P2+

ALERT SERVICE BULLETIN

SUBJECT: FUSELAGE -- Rear Structure

Visual inspection of ring frame X9227 (with blind rivet with rounded head

design) between rear structure tube and Fenestron housing for cracks

Revision No. Date of issue

Revision 0 2013-11-19

Summary:

In addition to the visual pre--flight check i.a.w. FLM EC135, a visual inspektion of the ring frame X9227

for cracks is introduced.

Compliance:

Compliance with this Alert Service Bulletin is mandatory.

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ASB EC135-53A-029

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1. PLANNING INFORMATION

1.A. EFFECTIVITY

1.A.1. Helicopters/installed equipment

(a) EC135, T1, T2, T2+, P1, P2, P2+, 635 T1, 635 T2+, 635 P2+, all S/N with more

than 100 fh TSN.

(b) Ring frame X9227 without frame reinforcement (View A, Figure 1): P/N L535H2120301

L535H2120303

L535H2120304

NOTE Ring frames with frame reinforcement L535H2100201 (View B, Figure 1) are

not affected.

1.A.2. Non--installed equipment

Not applicable.

1.B. ASSOCIATED REQUIREMENTS

Not applicable.

1.C. REASON

The rear structure tube is connected to the Fenestron housing by means of a ring frame attached

by two rivet rows each. During a postflight check a pilot detected a crack which ran along three

rivets over the ring frame.

1.D. DESCRIPTION

Inspect ring frame P/N L535H2120301, L535H2120303 and L535H2120304 for cracks.

1.E. COMPLIANCE

1.E.1. Compliance at the works

Helicopters/installed equipment:

Not applicable.

Non-installed equipment:

Not applicable.

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Revision 0, 2013-11-19 PAGE 3 of 7

1.E.2. Compliance in service

Helicopters/installed equipment:

(a) The visual inspection of ring frame X9227 i.a.w. Section 3.B. must be accomplished 50 fh

after receipt of this Alert Service Bulletin at the latest.

(b) The visual inspection of the ring frame X9227 must be repeated every 50 fh i.a.w. Section

3.B.

Non-installed equipment:

Not applicable.

1.F. APPROVAL

Approval of this document:

The technical content of this document is approved under the authority of

DOA No. EASA.21J.034.

1.G. MANPOWER

Not applicable.

1.H. WEIGHT AND BALANCE

Not applicable.

1.I. EFFECT ON ELECTRICAL LOADS

Not applicable.

1.J. SOFTWARE MODIFICATION EMBODIMENT RECORD

Not applicable.

1.K. REFERENCES

Not applicable.

1.L. DOCUMENTS AFFECTED

The visual pre--flight check of ring frame X9227 according to FLM EC135 remains unchanged.

1.M.INTERCHANGEABILITY OR MIXABILITY OF PARTS

Interchangeability:

Not applicable.

Mixability:

Not applicable.

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ASB EC135-53A-029

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2. MATERIAL INFORMATION

2.A. MATERIAL: PRICE - AVAILABILITY - PROCUREMENT

Not applicable.

2.B. INFORMATION CONCERNING INDUSTRIAL SUPPORT

Not applicable.

2.C. MATERIAL REQUIRED FOR EACH HELICOPTER/COMPONENT

Not applicable.

2.D. MATERIAL TO BE RETURNED

Not applicable.

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Revision 0, 2013-11-19 PAGE 5 of 7

3. ACCOMPLISHMENT INSTRUCTIONS

3.A. GENERAL

Not applicable.

3.B. OPERATIONAL PROCEDURE

3.B.1. Procedure

(a) Do the visual inspection for cracks on the ring frame, using a magnifying glass (at least

10--fold magnification) and a flashlight.

NOTE The transition area ring frame/rear structure tube and Fenestron housing is

sealed with a flexible sealing compound. Thus, paint cracks can form in this

area (View C, Figure 2).

(b) Cracks within the ring frame ( , Figure 2) and between the rivet heads are not

permissible. If cracks are detected in this area, ECD must be contacted before further

flight.

(c) If no cracks are detected or only paint cracks are shown proceed with Section 3.C.

3.C. IDENTIFICATION

Identification of this document:

Confirm accomplishment of this Alert Service Bulletin by an entry in the historical record of the

helicopter.

3.D. OPERATING AND MAINTENANCE INSTRUCTIONS

Flight Manual (FLM):

Not applicable.

Aircraft Maintenance Manual (AMM):

Not applicable.

4. APPENDIX

Not applicable.

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Identification of Ring Frame X9227

Figure 1

Transition area ring frame/rear structure tube.

Transition area ring frame/Fenestron housing.

Ring frame without frame

reinforcement

VIEW A

VIEW B

Ring frame with frame reinforcement

L535H2100201

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Revision 0, 2013-11-19 PAGE 7 of 7

Visual Check of Ring Frame X9227 for Cracks

Figure 2

Transition area ring frame/rear structure tube.

Transition area ring frame/Fenestron housing.

Cracks within the ring frame (red) are not permissible.

VIEW C

Paint cracks at the transitions of

the ring frame

Paint crack Paint crack

approx. 13 cm

to the end of

the ring frame

(5.12 inches)

approx. 4.8 cm to the beginning

of the ring frame (1.9 inches)

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