# ASB EC135-62A-029

PAGE 1 of 11 Revision 7, 2012-10-22 

### Effective for version(s): T1, T2, T2+, P1, P2, P2+ 635 T1, 635 T2+, 635 P2+ 

# ALERT SERVICE BULLETIN

SUBJECT : MAIN ROTOR SYSTEM -- Main Rotor Hub-Shaft Visual inspection of the upper and lower hub-shaft flange for cracks

Revision number Issue date Revision 0 2012-03-08 Revision 1 2012-05-16 Revision 2 2012-05-17 Revision 3 2012-08-09 Revision 4 2012-08-23 Revision 5 2012-09-10 Revision 6 2012-10-02 Revision 7 2012-10-22 

### Summary: During a PERIODICAL INSPECTION a crack was detected on the lower hub-shaft flange of a main rotor hub-shaft. Since Revision 0 of this Alert Service Bulletin 3 further cracks had been detected, while carrying out the preflight check.

Reason for the Revision: Revision 7 increases the compliance time for the visual inspection of the hub-shaft flanges according to Part 2 from 40 fh to 50 fh, based on the results from the full scale component testing. In addition, the note regarding the preflight check was revised. However, the measures remain the same. Please replace Revision 6 of Alert Service Bulletin EC135-62A-029 with Revision 7. Compliance: Compliance with this Alert Service Bulletin is prescribed. See Section 1.E.

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# ASB EC135-62A-029

PAGE 2 of 11 Revision 7, 2012-10-22 

### 1. PLANNING INFORMATION 1.A. EFFECTIVITY 1.A.1. Helicopters/installed equipment (a) EC135/EC635, all models. (b) Main rotor hub-shaft: all versions 1.A.2. Non--installed equipment Not applicable. 1.B. ASSOCIATED REQUIREMENTS Not applicable. 1.C. REASON During a PERIODICAL INSPECTION a crack was detected on the lower hub-shaft flange of a main rotor hub-shaft. Since Revision 0 of this Alert Service Bulletin 3 further cracks had been detected, while carrying out the preflight check. -- Revision 0 required a one--time visual inspection. -- Revision 1 and 2 introduced:
→ Part 1: a dedicated preflight check
→ Part 2: a repetitive visual inspection
→ Part 3: a visual inspection with removal of components, nut and washer. -- Revision 3 of this Alert Service Bulletin is based on experience gained and the supporting results from the full scale component test:

→ Part 1: The preflight check is incorporated in the Flight Manual. Additional supporting material for the accomplishment of the preflight check, as per the FLM, has been included to this ASB.
→ Part 3: is no longer required and was removed -- Revision 4 introduced:
→ Part 2: The visual inspection interval is increased from 10 fh to 15 fh.
→ Inspection requirements for main rotor hub-shafts with SB EC135-62-030 and/or SB EC135-62-032 incorporated are detailed. -- Revision 5 introduced:
→ Part 2: The visual inspection interval is increased from 15 fh to 25 fh. -- Revision 6 introduced:
→ Part 2: The visual inspection interval is increased from 25 fh to 40 fh. -- Revision 7 introduced:
→ Part 2: The visual inspection interval is increased from 40 fh to 50 fh. 1.D. DESCRIPTION If necessary, remove the rotor hub cap and, if necessary, the transmission fairings. Visual inspection of the upper and lower hub-shaft flange. If removed, install rotor hub cap and transmission fairings.

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# ASB EC135-62A-029

PAGE 3 of 11 Revision 7, 2012-10-22 

### 1.E. COMPLIANCE 1.E.1. Compliance at the works Helicopters/installed equipment EFFECTIVITY -- Main rotor hub-shafts with more than 400 fh TSN or -- Main rotor hub-shafts with more than 400 fh TSR* i.a.w. SB EC135-62-030

or -- Main rotor hub-shafts with more than 400 fh TSR* i.a.w. SB EC135-62-032. *Time Since Rework (last accomplished STEP). See Section 1.E.2. Non--installed equipment Not applicable. 1.E.2. Compliance in service Helicopters/installed equipment: EFFECTIVITY All helicopters Part 1: Preflight check - Blade attachment area of main rotor mast (upper and lower) (a) Inspection requirements have been moved to the FLM, required before every flight. Additional reference material and details for carrying out the preflight check are detailed in Section 3.B. Part 1. NOTE The time between two preflight checks must not exceed 6 fh.One flight may comprise multiple take--offs and landings. For the content of this Alert Service Bulletin, it is considered that a flight starts when the helicopter takes off, and ends when the helicopter is on ground with the engines shut off. EFFECTIVITY -- Main rotor hub-shafts with more than 400 fh TSN or -- Main rotor hub-shafts with more than 400 fh TSR* i.a.w. SB EC135-62-030

or -- Main rotor hub-shafts with more than 400 fh TSR* i.a.w. SB EC135-62-032. *Time Since Rework (last accomplished STEP). Part 2: Visual inspection of the upper and lower hub--shaft flange: (a) Accomplish the visual inspection of the upper and lower hub-shaft flange i.a.w. Section 3.B Part 2 within the next 50 fh after the last inspection Part 2 was carried out i.a.w. Revision 6 of this EASB. (b) Repeat the visual inspection of the upper and lower hub-shaft flange i.a.w. Section 3.B Part 2 every 50 fh thereafter.

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# ASB EC135-62A-029

PAGE 4 of 11 Revision 7, 2012-10-22 

### Part 3: Visual inspection of the blade bolt area: Inspection requirement removed with Revision 3. Non--installed equipment EFFECTIVITY -- Main rotor hub-shafts with more than 400 fh TSN or -- Main rotor hub-shafts with more than 400 fh TSR* i.a.w. SB EC135-62-030

or -- Main rotor hub-shafts with more than 400 fh TSR* i.a.w. SB EC135-62-032. *Time Since Rework (last accomplished STEP). Accomplish the visual inspection of the main rotor hub-shaft i.a.w. Section 3.B Part 2 before the main rotor hub-shaft is installed on the helicopter. 1.F. APPROVAL Approval of modifications: The technical content of this document is approved under the authority of DOA No. EASA.21J.034. 1.G. MANPOWER Qualification Mechanic Electrician Pilot Others Time approx. 0.5 h
-- -- -- 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 AMM EC135 and AMM EC135/635 FLM EC135/635 1.L. DOCUMENTS AFFECTED Not applicable. 1.M.INTERCHANGEABILITY OR MIXABILITY OF PARTS Interchangeability: Not applicable. Mixability: Not applicable.

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# ASB EC135-62A-029

PAGE 5 of 11 Revision 7, 2012-10-22 

### 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 EC135-62A-029

PAGE 6 of 11 Revision 7, 2012-10-22 

### 3. ACCOMPLISHMENT INSTRUCTIONS 3.A. GENERAL INFORMATION 

## Part 1 (Preflight check) Before each flight 

## Part 2 (Visual inspection) Every 5 0 fh Main rotor hub-shaft with less than 400 fh TSN X not applicable Main rotor hub-shaft with less than 400 fh TSR after last accomplisment of SB EC135- 62- 030 and/or SB EC135- 62- 032 X not applicable

Main rotor hub-shaft with more than 400 fh TSN X X Main rotor hub-shaft with more than 400 fh TSR after last accomplishment of SB EC135- 62- 030 and/or SB EC135- 62- 032 X X

Overview 3.B. OPERATIONAL PROCEDURE Part 1: Preflight check - Blade attachment area of main rotor mast (upper and lower) A. The inspection requirements have been moved to the preflight check in the FLM. Refer to Section 3.D of this Alert Service Bulletin for revision details. NOTE ECD recommends training of the flight crew to ensure that the revised contents of the FLM are clearly understood. Figure 1--3 have been provided for reference material in identifying the crack and paragraph B below provides the details for carrying out the preflight check. B. Details for carrying out the preflight check/turn around: (1) Clean the visible area of the upper and lower hub-shaft flanges of the main rotor hub-shaft. (2) Check the visible blade attachment area of the main rotor hub-shaft (upper and lower hub--shafts) for condition and cracks i.a.w. Figure 1. If necessary, use a flashlight. Figure 3 shows a survey of all detected cracks and the location. a. If cracks are detected during the preflight check, contact the maintenance staff / ECD customer support. The rotor hub-shaft must be replaced before the next flight.

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# ASB EC135-62A-029

PAGE 7 of 11 Revision 7, 2012-10-22 

### Part 2: Visual inspection of the upper and lower hub--shaft flange: A. Preliminary steps: (1) If necessary, remove rotor hub cap i.a.w. AMM, 62-31-00, 4-1. (2) If necessary, remove LH and RH transmission fairing i.a.w. AMM, 71-11-00, 4-4. B. Inspect the upper and lower hub-shaft flanges for cracks: (1) Clean the visible area of the upper and lower hub-shaft flanges of the main rotor hub-shaft i.a.w. Figure 2 and inspect for cracks. If necessary, use a flashlight and a mirror. Paint imperfections are to be inspected with a magnifying glass or a micro camera. (2) If cracks are detected during the visual inspection, contact ECD customer support. The rotor hub-shaft must be replaced before the next flight. (3) If previously removed, install rotor hub cap i.a.w. AMM, 62-31-00, 4-1. (4) If previously removed, install LH and RH transmission fairing i.a.w. AMM, 71-11-00, 4-4. C. Confirm accomplishment of Part 2 i.a.w. Section 3.C.

Part 3: Visual inspection of the blade bolt area: Inspection procedure removed with Revision 3. 3.C. IDENTIFICATION Accomplishment of this document: Confirm accomplishment of this Alert Service Bulletin by an entry in the historical record of the helicopter and in the log card of the main rotor hub-shaft: Part 2: ”Visual inspection of the upper and lower hub-shaft flanges”

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# ASB EC135-62A-029

PAGE 8 of 11 Revision 7, 2012-10-22 

### 3.D. OPERATING AND MAINTENANCE INSTRUCTIONS Flight manual: The step added to the preflight check (main rotor area) has been distributed with the following Temp. Revs of the FLM: -- EC 135 T2+ Temp. Rev.5 -- EC 135 P2+ Temp. Rev.5 -- EC 635 T2+ Temp. Rev.5 -- EC 635 P2+ Temp. Rev.5 -- EC 135 P2 (CPDS) Temp. Rev.10 -- EC 135 T2 (CPDS) Temp. Rev.12 -- EC 135 T1 (CPDS) Temp. Rev.17 -- EC 635 T1 (CPDS) Temp. Rev.17 -- EC 135 P1 (CPDS) Temp. Rev.13 -- EC 135 T1 (CDS) Temp. Rev.23 -- EC 135 P1 (CDS) Temp. Rev.19 AMM/maintenance manual: No changes.



### 4. APPENDIX Not applicable.

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# ASB EC135-62A-029

PAGE 9 of 11 Revision 7, 2012-10-22 

### Preflight Check / Turn Around -- Upper and Lower Hub--Shaft Flanges Figure 1 Check the visible area of the upper hub--shaft flange for cracks. Check the visible area of the lower hub--shaft flange for cracks. Example for cracks in the lower hub--shaft flange. Crack

Crack

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# ASB EC135-62A-029

PAGE 10 of 11 Revision 7, 2012-10-22 

### Main Rotor Hub--Shaft -- Upper and Lower Hub--Shaft Flanges Figure 2 Upper hub--shaft flange

Lower hub--shaft flange

Main rotor hub--shaft

Inspect the visible area of the upper and lower hub--shaft flanges.

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# ASB EC135-62A-029

PAGE 11 of 11 Revision 7, 2012-10-22 

### Support to Accomplish the Preflight Check/ Turn Around Figure 3

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