# ASB EC135-53A-029

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## 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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# ASB EC135-53A-029

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## 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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# ASB EC135-53A-029

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# 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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# ASB EC135-53A-029

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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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# ASB EC135-53A-029

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## 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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