EASA AD No : 2010-0172-E

EASA Form 111 Page 1/4 

## EASA EMERGENCY AIRW ORTHINESS DIRECTIVE

AD No.: 2010-0172-E Corrected: 19 August 2010

Date: 18 August 2010

Note: This Emergency Airworthiness Directive (A D) is issued by EASA, acting in accordance with Regulation (EC) No 216/2008 on behalf of the European Community, its Member States and of the European third countries that participat e in the activities of EASA under Article 66 of that Regulation.
This AD is issued in accordance with EC 1702/2003, Part 21A .3B. In accordance with EC 2042/2003 Annex I, Part M.A.301, the continuing airworthiness of an aircraft shall be ensured by accomplishing any applicable ADs. Consequently, no person may opera te an aircraft to which an AD applies, except in accordance with th e requirements of that AD unless otherwise specified by the Age ncy [EC 2042/2003 Annex I, Part M.A.303] or agreed with the Authority of the State of Registry [EC 216/2008, Article 14(4) exemptio n]. 

### Type Approval Holder’s Name : MD Helicopters, Inc. Type/Model designation(s) : MD900 helicopters

TCDS Number : United States (FAA) H19NM

Foreign AD : None

Supersedure : None



### ATA 62 Main Rotor – Main Rotor (MR) Lower Hub Assembly – Inspection

Manufacturer(s): MD Helicopters, Inc. (MDHI), Mc Donnell Douglas Helicopter Systems (MDHS).
Applicability: MD900 helicop ters, all serial numbers. Some helicopters may have the designa tion MD-900 on the data plate; these helicopters belong to the same type des ign and consequently, this AD applies to those helicopters.
Reason: A crack has been reported on a Part Number (P/N) 900R2101008-107 MR lower hub. As the investigation into the cause(s) of this crack was initiated, MDHI published a Notice to inform all affected owners and operators, requesting that special attention be given to the MR (lower) hub assembly during daily pre-flight and scheduled 100 hour inspections, to detect any cracks or other anomalies and to request that any discrepancies are reported to MDHI. Prompted by the MDHI Notice, another cracked hub has been found. In light of the early failures of these hu bs (at the time of the detection, one part is known to have accumulated only so me 2 400 FH; the part design life limit has been established at 10 750 FH) when compared to the overall fleet size and accumulated time in service, these failures may be due to unique causes, but this cannot be determined without additional data and further investigation. For the reasons described above, pending the result of the investigation and in support thereof, this Emergency AD requires a one-time detailed visualEASA AD No : 2010-0172-E

EASA Form 111 Page 2/4 inspection of the MR lower hub, corrective action depending on findings, and the reporting of all findings (including none) to MDHI, copy to EASA, to ensure that sufficient data is obtained and communicated to the TC Holder in a short timescale.
This AD is considered to be an interim measure, until a cause is established to explain the reported cracks and consequent corrective measures are introduced by the approval holder of the type design. This AD has been republished to corr ect a typographical error in a Part Number, referenced in the first paragrap h of the Reason section of this AD.
Effective Date: 20 August 2010

Required Action(s) and Compliance Time(s): Required as indicated, unless accomplished previously:
(1) Before next flight after the effectiv e date of this AD, accomplish a detailed visual inspection of the MR lower hub assembly, as defined in Section 05of the MD900 Rotorcraft Maintenance Manual, publication CSP900RMM-2, paying particular attention to the material directly outboard and inboard of the five P/N 900R2100011 main rotor hub flex-beam bolts. Images can be found in the MDHI Notice dated 11 August (which was sent to all operators) and in the sample photograph provided in Appendix 1 of this AD.
(2) If a crack is detected during the inspection as required by paragraph (1) of this AD, or during any pre-flight or other inspection, before next flight, contact MDHI (address details in t he Remarks section of this AD) for approved repair or replacement instructions and accomplish those instructions accordingly.
(3) Within 3 days after the inspection as required by paragraph (1) of this AD, send a full report, including no findings, to MD Helicopters, and in copy to EASA by using the Reporting Form in Appendix 2 of this AD.
Ref. Publication(s): MD900 Rotorcraft Maintenance Manual, CSP-900RMM-2.
MDHI Notice dated 11 August 2001, subject: ‘Discovery of a crack on a Main Rotor Hub Lower Assembly’.

Remarks : 1. If requested and appropriately substantiated, EASA can approve Alternative Methods of Compliance for this AD.
2. The safety assessment has requested not to implement the full consultation process and an immedi ate publication and notification.
3. Enquiries regarding this AD should be referred to the Airworthiness Directives, Safety Management & Re search Section, Certification Directorate, EASA. E-mail ADs@easa.europa.eu

. 4. For any question concerning the tec hnical content of the requirements in this AD, please contact: MD Helicopters Inc., Attn: Customer Support Division, 4555 East McDowell Road, Mail Stop M615, Mesa, Arizona 85215-9734, United States of America. Telephone +1-800-388-3378, fax +1-480-346-6813 Website http://www.mdhelicopters.com

. E-mail serviceengineering@mdhelicopters.com

.EASA AD No : 2010-0172-E

EASA Form 111 Page 3/4 

### Appendix 1 Sample photograph of an MD900 Main Rotor Lower Hub

A detailed visual inspection is required for the areas (o n all five faces of the lower hub, radially outboard and inboard of each main rotor hub flex-beam bolt; P/ N 900R2100011), as indicated by the arrows above.EASA AD No : 2010-0172-E

EASA Form 111 Page 4/4 

### Appendix 2
MD900 MR LOWER HUB INSPECTION REPORT

Aircraft Serial Number: Registration:

Part Number Serial Number MR Lower Hub

Since new Since Installation Total time accumulated

Crack(s) found: Yes F No F
[in case of findings, provide details here]



### Send to: MD Helicopters Inc., Attn: Field Service Engineering, Fax +1-480-346-6813, E-mail serviceengineering@mdhelicopters.com

. Copy to: EASA, Certification Directorate, Airworthiness Directives, Safety Management & Research Section, Fax +49 221 899 90 9512, E-mail ADs@easa.europa.eu

.