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

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

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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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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Revision 2, 2014-03-04 PAGE 3 of 13

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

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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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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Revision 2, 2014-03-04 PAGE 7 of 13

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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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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Revision 2, 2014-03-04 PAGE 9 of 13

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

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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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 2 4

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

1

Installation -- Shock attenuator

Figure 10

2

3

1 Bonding probe

2 Damper housing

3 Bonding straps

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