Emergency AD

ID: 2016-0166-E
Status: Current
Effective date: 2017-10-04  
Source: EASA
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Leonardo S.p.A AB204/AB205, AB212/AB412 Helicopters: Main Rotor Drive - Spiral Bevel Gear - Inspection

EASA AD No.: 2016-0166-E


Emergency Airworthiness Directive
AD No.: 2016-0166-E
[Correction: 04 October 2017]
Issued: 12 August 2016
Note: This Emergency Airworthiness Directive (AD) is issued by EASA, acting in accordance with
Regulation (EC) 216/2008 on behalf of the European Union, its Member States and of the
European third countries that participate in the activities of EASA under Article 66 of that
Regulation.

This AD is issued in accordance with Regulation (EU) 748/2012, Part 21.A.3B. In accordance with Regulation (EU) 1321/2014 Annex I, Part M.A.301, the
continuing airworthiness of an aircraft shall be ensured by accomplishing any applicable ADs. Consequently, no person may operate an aircraft to which
an AD applies, except in accordance with the requirements of that AD, unless otherwise specified by the Agency [Regulation (EU) 1321/2014 Annex I,
Part M.A.303] or agreed with the Authority of the State of Registry [Regulation (EC) 216/2008, Article 14(4) exemption].


Design Approval Holder’s Name: Type/Model designation(s):
LEONARDO S.p.A. AB204B, AB205A1, AB212 and AB412
helicopters

Effective Date:
16 August 2016
TCDS Number(s): ENAC Italy SO/A-150 and EASA.R.114
Foreign AD: Not Applicable
Supersedure: This AD supersedes EASA Emergency AD 2016-0153-E dated 27 July 2016.


ATA 63 – Main Rotor Drive – Spiral Bevel Gear – Inspection


Manufacturer(s):

AgustaWestland S.p.A. (formerly Agusta S.p.A., Costruzioni Aeronautiche Giovanni Agusta)

Applicability:

AB204B, AB205A1 and AB212 helicopters, all serial numbers (s/n) and AB412 helicopters all s/n up
to s/n 25669 inclusive.

Reason:

During a scheduled inspection of a main rotor transmission, Part Number (P/N) 212-040-001-59, a
crack was found on the spiral bevel gear, P/N 204-040-701-103. The initial investigation determined
that the crack had originated from the bottom of one of 32 threaded holes and that other spiral
bevel gears, manufactured with the same process as the defective one, could be affected by the
same issue.

This condition, if not detected and corrected, could lead to failure of the main rotor transmission,
possibly resulting in loss of control of the helicopter.

To address this potential unsafe condition, Finmeccanica Helicopter Division (FHD) issued Bollettino
Tecnico (BT) 412-146, later revised, providing instructions for identification and repetitive

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Fluorescent Magnetic Particle Inspection (FMPI) of affected spiral bevel gears. To accomplish the
FMPI, the spiral bevel gear has to be removed from the main rotor transmission that has to be
removed from the helicopter. Consequently, EASA issued Emergency AD 2016-0136-E, requiring
identification and repetitive inspections of the affected spiral bevel gears and, depending on
findings, replacement.

After EASA AD 2016-0136-E was issued, it was determined that the same P/N spiral bevel gears are
eligible for installation on AB212 helicopters, which are therefore potentially affected by the same
unsafe condition. Consequently, Leonardo S.p.A. Helicopters (LSH) issued BT212-207 and EASA
issued Emergency AD 2016-0153-E, retaining the requirements of AD 2016-0136-E, which was
superseded, and expanding the Applicability to include AB212 helicopters.

Since that AD was issued, it was determined that the same P/N spiral bevel gears are also eligible
for installation on AB204B and AB205A1 helicopters, which are therefore potentially affected by the
same unsafe condition. Prompted by this finding, LSH issued BT 204-128 and BT 205A1-136. FHD
BT 412-146 revision (rev.) A, LSH BT 212-207, BT 204-128 and BT 205A1-136 (hereafter collectively
referred to as “the applicable BT” in this AD) all have the same technical content, but are applicable
to different helicopters.

For the reason stated above, this AD retains the requirements of AD 2016-0153-E, which is
superseded, and expands the Applicability to include AB204B and AB205A1 helicopters.

This AD is still considered an interim action and further AD action may follow.

This AD is republished to correct typographical errors in the Reason section.

Required Action(s) and Compliance Time(s):

Required as indicated, unless accomplished previously:

Note 1: For the purpose of this AD, an affected spiral bevel gear is a part having
P/N 204-040-701-103, and a s/n as listed in Table 1 of this AD.

Table 1 – Affected Spiral Bevel Gear
A0616 A0628 A2 0647 A2 0660 B27335 C45374 E28465
A0617 A0629 A2 0648 A2 0661 B27337 C45375
A0618 A0631 A2 0650 B27326 C45369 C45376
A0619 A0635 A2 0651 B27327 C45370 C45377
A0620 A0637 A2 0652 B27329 C45371 C45378
A0621 A2 0644 A2 0653 B27330 C45372 C45379
A0624 A2 0646 A2 0659 B27333 C45373 E28464

(1) Within the compliance time as specified in Table 2 of this AD, as applicable, inspect the
helicopter to determine the s/n of the spiral bevel gear P/N 204-040-701-103, in accordance
with the instructions of Part I of the applicable BT.


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Table 2 – Spiral Bevel Gear Identification
Helicopter Compliance Time
AB204B,
Within 10 flight hours (FH) after the effective date of this AD
AB205A1
AB212 Within 10 FH after 29 July 2016 [the effective date of AD 2016-0153-E]
AB412 Within 10 FH after 12 July 2016 [the effective date of AD 2016-0136-E]

(2) If, during the inspection as required by paragraph (1) of this AD, it is determined that an
affected s/n spiral bevel gear is installed, before next flight, inspect that spiral bevel gear in
accordance with the instructions of Part I of the applicable BT.

(3) If, during the inspection as required by paragraph (2) of this AD, any crack is found on the
affected spiral bevel gear, before next flight, replace that spiral bevel gear with a serviceable
one (see Note 3 of this AD) in accordance with the instructions of Part I of the applicable BT.

As an alternative to replacing the spiral bevel gear, replace the main rotor transmission with a
main rotor transmission equipped with a serviceable spiral bevel gear (see Notes 2 and 3 of this
AD).

Note 2: Using the instructions of BHT-204B-M&O, Section IV, or BHT-205A1-MM Chapter 66, or
BHT-212-MM Chapter 63, or AB412-MM, Chapter 63-22, as applicable, is an acceptable method to
replace a main rotor transmission.

Note 3: For the purpose of this AD, a serviceable spiral bevel gear P/N 204-040-701-103 is a part
that does not have a s/n as listed in Table 1 of this AD; or an affected part (see Note 1 of this AD)
that has accumulated less than 1 200 FH since first installation on a helicopter, or has accumulated
less than 300 FH since passing an FMPI in accordance with the instructions of Part II of
any of the applicable BTs.

(4) Following the inspection as required by paragraph (1) of this AD, before the affected spiral
bevel gear exceeds 1 200 FH since first installation on a helicopter (see Note 4 of this AD), or
within 100 FH after the inspection as required by paragraph (1) of this AD, whichever occurs
later, and, thereafter, at intervals not to exceed 300 FH, accomplish an FMPI of that affected
spiral bevel gear (see Note 1 of this AD) in accordance with the instructions of Part II of the
applicable BT.

As an alternative to an FMPI as required by paragraph (4) of this AD, replace the main rotor
transmission with a main rotor transmission equipped with a serviceable spiral bevel gear (see
Notes 2 and 3 of this AD). If the replacement spiral bevel gear is an affected part (see Note 1 of
this AD), the next FMPI is due within the time specified in Table 3 of this AD.

Note 4: For the purpose of this AD, if the FH accumulated since first installation on a helicopter of
an affected spiral bevel gear are not known, the total time accumulated by the main rotor
transmission since its first installation on a helicopter applies instead.



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Table 3 – Next FMPI after installation of an affected spiral bevel gear

FH accumulated by the Spiral Bevel Gear
Compliance Time
(see Note 4 of this AD)
Less than 1 200 FH since first installation on a Before exceeding 1 200 FH since first
helicopter installation on a helicopter
Less than 300 FH since passing an FMPI in
accordance with the instructions of Part II of Before exceeding 300 FH after the last FMPI
any of the applicable BTs

(5) From 29 July 2016 [the effective date of AD 2016-0153-E], installation on a AB212 helicopter of
a main rotor transmission equipped with an affected spiral bevel gear (see Note 1 of this AD) is
allowed, provided that the spiral bevel gear is a serviceable part (see Note 3 of this AD).

(6) From 12 July 2016 [the effective date of AD 2016-0136-E], installation on a AB412 helicopter of
a main rotor transmission equipped with an affected spiral bevel gear (see Note 1 of this AD) is
allowed, provided that the spiral bevel gear is a serviceable part (see Note 3 of this AD).

(7) From the effective date of this AD, installation on an AB204B or AB205B1 helicopter of a main
rotor transmission equipped with an affected spiral bevel gear (see Note 1 of this AD) is
allowed, provided that the spiral bevel gear is a serviceable part (see Note 3 of this AD).

Ref. Publications:

Leonardo S.p.A. Helicopters BT 204-128 original issue, dated 10 August 2016.

Leonardo S.p.A. Helicopters BT 205A1-136 original issue, dated 10 August 2016.

Leonardo S.p.A. Helicopters BT 212-207 original issue, dated 25 July 2016.

Finmeccanica Helicopter Division BT 412-146 rev. A, dated 07 July 2016.

The use of later approved revisions of these documents is acceptable for compliance with the
requirements of this AD.

Remarks:
1. If requested and appropriately substantiated, EASA can approve Alternative Methods of
Compliance for this AD.

2. The results of the safety assessment have indicated the need for immediate publication and
notification, without the full consultation process.

3. Enquiries regarding this AD should be referred to the EASA Safety Information Section,
Certification Directorate. E-mail: ADs@easa.europa.eu.

4. For any question concerning the technical content of the requirements in this AD, please
contact: Leonardo S.p.A. Helicopters, Customer Support & Services
Product Support Engineering DPT, via Giovanni Agusta 520,

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EASA AD No.: 2016-0166-E

21017 Cascina Costa di Samarate (VA) – Italy
Tel.: +39 0331 711439, Fax: +39 0331 225988,
E-mail: absereng.AW@leonardocompany.com.




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This is a partial extract of the full document - please refer to the actual report for full information.
Sources as credited.