EASA AD No : 2010-0172-E 

EASA Form 111 Page 1/4 

EASA EMERGENCY AIRWORTHINESS DIRECTIVE 

AD No.: 2010-0172-E 

Corrected: 19 August 2010 

Date: 18 August 2010 

Note: This Emergency Airworthiness Directive (AD) 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 participate 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 operate 

an aircraft to which an AD applies, except in accordance with the requirements of that AD unless otherwise specified by the Agency 

[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) exemption]. 

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), McDonnell Douglas Helicopter Systems 

(MDHS). 

Applicability: MD900 helicopters, all serial numbers. 

Some helicopters may have the designation MD-900 on the data plate; these 

helicopters belong to the same type design 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 hubs (at the time of the detection, one part 

is known to have accumulated only some 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 visual 
EASA 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 correct a typographical error in a Part 

Number, referenced in the first paragraph 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 effective date of this AD, accomplish a detailed 

visual inspection of the MR lower hub assembly, as defined in Section 05 

of 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 the 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 immediate publication and notification. 

3. Enquiries regarding this AD should be referred to the Airworthiness 

Directives, Safety Management & Research Section, Certification 

Directorate, EASA. E-mail ADs@easa.europa.eu. 

4. For any question concerning the technical 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 (on 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.