## ASB MBB-BK117 C-2-85A-041

PAGE 1 of 13 Revision 2, 2014-03-04 Valid for Version(s): C-2. 

# EMERGENCY 

# ALERT SERVICE BULLETIN

SUBJECT : OPTIONAL EQUIPMENT -- External Mounted Hoist System Unintended detachment of hoist damper unit

Revision No. Date of issue Revision 0 2013-12-18 Revision 1 2014-02-27 Revision 2 2014-03-04 Summary: With Revision 2 of this Emergency Alert Service Bulletin, Airbus Helicopters Deutschland introduces the measures to reactivate the Goodrich hoist damper units.
Reason for last Revision: Please replace Revision 1 of Emergency Alert Service Bulletin MBB-BK117 C-2-85A-041 with Revision 2. With the Revision 2 of this Emergency Alert Service Bulletin, Airbus Helicopters Deutschland introduces the modification of the bonding strap unit, an improved retaining ring and a repetitive inspection. Compliance: Airbus Helicopters considers the compliance with this Emergency Alert Service Bulletin as mandatory.

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## ASB MBB-BK117 C-2-85A-041

PAGE 2 of 13 Revision 2, 2014-03-04 

### 1. PLANNING INFORMATION 1.A. EFFECTIVITY 1.A.1. Helicopters/installed equipment (a) MBB-BK117 C-2, all S/N, equipped with Goodrich external mounted hoist. (b) Goodrich hoist damper unit: P/N 44307--480 P/N 44307--480--1 P/N 44307--480--2 1.A.2. Non-installed equipment See Section 1.A.1.(b). 1.B. ASSOCIATED REQUIREMENTS Not applicable. 1.C. REASON Airbus Helicopters Deutschland was informed of incidents during which the cable unintentionally detached from the Goodrich rescue hoist damper units while the unloaded unit was being lifted by hand. The incidents were caused by a retaining ring, which was not located at its correct installation position. During the incidents known so far, the Hoist Damper Units never became detached under strain, but exclusively when unloaded (i.e. in the absence of tension between the cable and the damper). Further investigations have revealed that, during operation, the bonding strap unit may cause the retaining ring to separate from its groove, thus provoking the incident. With the Revision 2 of this Emergency Alert Service Bulletin, Airbus Helicopters Deutschland introduces the modification of the bonding strap unit, an improved retaining ring and a repetitive inspection. 1.D. DESCRIPTION Modify the bonding strap. Replace retaining ring by an improved one. 1.E. COMPLIANCE 1.E.1. Compliance at the works Helicopters/installed equipment: The bonding strap unit must be modified and the retaining ring must be replaced IAW Section 3.B.1. before delivery of the helicopter with Goodrich external mounted hoist. Non-installed equipment: The bonding strap unit must be modified and the retaining ring must be replaced IAW Section 3.B.1. before delivery of the hoist damper units. 1.E.2. Compliance in service Helicopters/installed equipment: (a) The bonding strap unit must be modified and the retaining ring must be replaced IAW Section 3.B.1. before next hoist operation.

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## ASB MBB-BK117 C-2-85A-041

PAGE 3 of 13 Revision 2, 2014-03-04 (b) After accomplishment of Section 3.B.1. the correct installation of the retaining ring must be inspected IAW Section 3.B.2. every 100 hoist cycles and with every cable change. Non-installed equipment: The bonding strap unit must be modified and the retaining ring must be replaced IAW Section 3.B.1. before installation of the hoist damper units. 1.F. APPROVAL Approval of the modification(s): The information or instructions contained in this document refer to change no. 3170. 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

Man hours approx. 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 Not applicable. 1.L. DOCUMENTS AFFECTED Not applicable. 1.M.INTERCHANGEABILITY OR MIXABILITY OF PARTS Interchangeability: Not applicable. Mixability: Not applicable.

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## ASB MBB-BK117 C-2-85A-041

PAGE 4 of 13 Revision 2, 2014-03-04 

### 2. MATERIAL INFORMATION 2.A. MATERIAL: PRICE -- AVAILABILITY -- PROCUREMENT Information on price and availability of required retrofit kit SB-117C2-85A-041-2C will be provided by Airbus Helicopters Deutschland, Dept. Spares Order Administration on request. 2.B. INFORMATION CONCERNING INDUSTRIAL SUPPORT Not applicable. 2.C. MATERIAL: PRICE - AVAILABILITY - PROCUREMENT Kits or components to be ordered for one helicopter or one assembly: Retrofit kit SB-117C2-85A-041-2C IAW design document B851M2016881 and B851M2061101.

No. Keyword Qty New P/N Old P/N Remark

1 Retaining ring 1 M2742630109D or AS3217--109 -- A

-- VH--75--S02
-- Remark: A = The retaining ring is a standard norm part and can be ordered locally.
Consumable materials to be ordered separately: Consumable materials have to be ordered by the INTERTURBINE AVIATION LOGISTICS company. The given CM numbers are IAW the AMM list of consumable materials. Website: http://www.interturbine.com Phone: +49.41.91.809.300 AOG: +49.41.91.809.444

No. Keyword Qty. Specification ** CM Remark

1 Laquer, single layer a.n.*



### -- 421 -- *a.n. = as needed ** Specification IAW AMM, 01-00-00, 2-1. 2.D. INFORMATION CONCERNING INDUSTRIAL SUPPORT Not applicable. 2.E. MATERIAL REQUIRED FOR EACH HELICOPTER/COMPONENT Not applicable. 2.F. MATERIAL TO BE RETURNED Not applicable.

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## ASB MBB-BK117 C-2-85A-041

PAGE 5 of 13 Revision 2, 2014-03-04 

### 3. ACCOMPLISHMENT INSTRUCTIONS 3.A. GENERAL Not applicable. 3.B. OPERATIONAL PROCEDURE 3.B.1. Modification of the hoist damper unit (a) Disassemble the hook assembly as follows: NOTE The hook mount (4, Figure 1) and the damper housing (1) are a serialized matched set. 1 Remove the lock spring (3, Figure 1) from the hook mount (4). 2 Unscrew the hook (5) together with the hook mount (4) and the attached bonding strap unit (2) from the damper housing (1). 3 Pull the bonding strap unit (2) together with the hook (5) and the hook mount (4) out of the damper housing (1). (b) Modify the bonding strap unit as follows: NOTE If a radius gauge with radius 3.2 mm is not available, manufacture a gauge out of sheet metal and a 6.4 mm drill (see Figure 2 and 3). NOTE Be careful to only round off the corners without shortening the total length of the bonding strap legs. 1 By using a radius gauge with 3.2 mm radius, round off the corners at the end of each bonding strap leg using a suitable tool i.e. a file, a grinder, etc. IAW Figure 4 and Figure 5. 2 Deburr and round all edges at the bonding strap ends IAW Figure 5 and Figure 6. 3 Remove all metal chips with a vaccum cleaner. 4 Using a permanent pen, cross out the old P/N on the bonding strap unit but leave it still legible and write part number “B851M2061101” close to the old P/N (see Figure 1). Protect identification with laquer, single-layer (CM 421). Let laquer, single-layer dry IAW manufacturer’s instruction. (c) Reassemble the hook assembly as follows: NOTE The hook mount (4, Figure 1) and the damper housing (1) are a serialized matched set. 1 Push the bonding strap unit (2) together with the hook (5) and the hook mount (4) inside the damper housing (1). 2 Ensure that the tips of the bonding straps (1, Figure 7) are placed over the bonding probe (2) inside the damper housing (3). 3 Screw the hook (5, Figure 1) together with the hook mount (4) and the attached bonding strap unit (2) into the damper housing (1). 4 Install the lock spring (3) at the hook mount (4).

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## ASB MBB-BK117 C-2-85A-041

PAGE 6 of 13 Revision 2, 2014-03-04 (d) Replace the retaining ring in the shock attenuator as follows: NOTE To get better access reel out the hoist cable approx. 2 meters. 1 Remove the lock spring (3, Figure 8) from the shock attenuator (2). 2 Unscrew the shock attenuator (2) from the damper housing (1). NOTE The shock attenuator (2, Figure 8) and the damper housing (1) are a serialized matched set. 3 Remove the retaining ring (3, Figure 9) and discard. 4 Install the new retaining ring (4) in the groove (2) of the shock attenuator (1). 5 Push the shock attenuator (2, Figure 8) inside the damper housing (1). 6 Ensure that the tips of the bonding straps (3, Figure 10) are placed over the bonding probe (1) inside the damper housing (2). 7 Screw the shock attenuator (2, Figure 8) into the damper housing (1). 8 Install the lock spring (3) in the shock attenuator (2). (e) Reactivate the Goodrich hoist, if deactivated with Revision 1 of this Emergency Alert Service Bulletin, as follows:

1 Remove ty-raps and push the following circuit breakers: -- WINCH BOOM, -- WINCH CONT, -- CC PIL WINCH, -- CC PED WINCH. 2 Remove the placard printed with “External Mounted Hoist deactivated” affixed within the pilot’s visual range. (f) Using a permanent pen, identify the damper housing close to its P/N with “EASB-85A-041 Rev 2” (see Figure 8). Protect identification with laquer, single-layer (CM 421). Let laquer, single-layer dry IAW manufacturer’s instruction. 3.B.2. Inspection of the retaining ring (a) Disassemble the hook assembly as follows: NOTE To get better access reel out the hoist cable approx. 2 meters. 1 Remove the lock spring (3, Figure 8) from the shock attenuator (2). 2 Unscrew the shock attenuator (2) from the damper housing (1). 3 Visually inspect the retaining ring (4, Figure 9) and make sure that it is undamaged and correctly installed in the groove (2) of the shock attenuator (1). 4 If the retaining ring (4) is damaged and/or not in the correct position, contact Airbus Helicopters Deutschland for further instructions. 5 Push the shock attenuator (2, Figure 8) inside the damper housing (1). 6 Ensure that the tips of the bonding straps (3, Figure 10) are placed over the bonding probe (1) inside the damper housing (2). 7 Screw the shock attenuator (2, Figure 8) inside the damper housing (1). 8 Install the lock spring (3) in the shock attenuator (2).

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## ASB MBB-BK117 C-2-85A-041

PAGE 7 of 13 Revision 2, 2014-03-04 3.C. IDENTIFICATION Accomplishment of this document: Confirm accomplishment of this Emergency Alert Service Bulletin by an entry in the historical record of the helicopter and the log card of the respective parts. Identification of modification of equipment: Keyword Old P/N New P/N MOD Remark Damper housing

-- 

### -- EASB-85A-041 Rev 2 Permanent pen Bonding strap unit 44307--475 B851M2061101



### -- Permanent pen 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 MBB-BK117 C-2-85A-041

PAGE 8 of 13 Revision 2, 2014-03-04 Removal -- Bonding strap Figure 1 1 Damper housing 2 Bonding strap unit 3 Lock spring 4 Hook mount 5 Hook 1

2

3

Round off corners at the end of each bonding strap leg. 4

5 Identify with “B851M2061101”.

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## ASB MBB-BK117 C-2-85A-041

PAGE 9 of 13 Revision 2, 2014-03-04 Self--made -- radius gauge Figure 2 Sheet metal

6.4 mm diameter Cut after drilling

Self--made radius gauge Figure 3

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## ASB MBB-BK117 C-2-85A-041

PAGE 10 of 13 Revision 2, 2014-03-04 Bonding strap before modification Figure 4

Bonding strap after modification Figure 5 Round off the corners at the end of each bonding strap leg. Be careful to only round off the corners without shortening the total length of the bonding strap legs.

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## ASB MBB-BK117 C-2-85A-041

PAGE 11 of 13 Revision 2, 2014-03-04

1 Bonding strap 2 Bonding probe 3 Damper housing Reworked bonding strap Figure 6 Deburr and round off all edges of the reworked bonding strap ends.

Reassembly -- Hook assembly Figure 7 1

3

2

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## ASB MBB-BK117 C-2-85A-041

PAGE 12 of 13 Revision 2, 2014-03-04 Installation -- Retaining ring Figure 9 2 1

1

3

1 2 3 Removal -- Shock attenuator Figure 8 Identify with “EASB-85A-041 Rev 2”. 1 Damper housing 2 Shock attenuator 3 Lock spring

1 Shock attenuator 2 Groove 3 Old retaining ring VH--75--S02 4 New retaining ring M2742630109D or AS3217--109 2 3

1 4 2

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## ASB MBB-BK117 C-2-85A-041

PAGE 13 of 13 Revision 2, 2014-03-04 1

Installation -- Shock attenuator Figure 10 2

3 1 Bonding probe 2 Damper housing 3 Bonding straps

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