EASA AD No.: 2009-0051 

EASA Form 110 Page 1/2 

EASA AIRWORTHINESS DIRECTIVE 

AD No.: 2009-0051 

Date: 05 March 2009 

Note: This 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 Airworthiness Directive applies, except in accordance with the requirements of that Airworthiness Directive 

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 : 

ROLLS-ROYCE PLC 

Type/Model designation(s) : 

RB211 Trent 900 series engines 

TCDS Number : EASA.E.012 

Foreign AD : Not applicable 

Supersedure : This AD supersedes EASA AD 2008-0202, dated 17 November 2008. 

ATA 72 Engine – HP Turbine Nozzle Guide Vane (NGV) Convex Surface -

Inspection 

Manufacturer(s): Rolls-Royce plc 

Applicability: RB211 Trent 900 series engines, all marks, which do not incorporate 

modification SB 72-G025. 

These engines are known to be installed on, but not limited to, Airbus A380 

series aeroplanes. 

Reason: Evidence from development testing and flight test Trent 900 engines has 

identified cracking on some HP Turbine Nozzle Guide Vane (NGV) Convex 

Surfaces. Analysis of test data and review of the manufacturing process has 

revealed compounding effects that may contribute to a shortfall in component life 

and an increased likelihood of premature cracking in this region. Excessive 

cracking on the Convex Surface may lead to the release of NGV material or the 

blockage of Turbine gas flow. This results in a risk of fracture to the HP Turbine 

Blade. 

Not all NGV assemblies are affected. It is believed that the problem, if it exists, 

will manifest itself below 1000 cycles. 

Single release of HP Turbine Blade on more than one engine could result in 

multiple engine loss of power or In-Flight Shut Down (IFSD). This event presents 

a potential unsafe condition to the aeroplane. 

EASA AD 2008-0202 was published to require inspection of the HPT NGV 

Convex Surfaces and, depending on the results, subsequent corrective actions. 

Since issuance of EASA AD 2008-0202 Rolls-Royce plc has inspected several 

sets of HPT NGV’s returning from service, and determined that tighter limits are 

needed on some dimensions for some types of damage. It has also been 
EASA AD No.: 2009-0051 

EASA Form 110 Page 2/2 

determined that relaxed inspection intervals can be allowed for some type of 

damage and when no damage is found. These new limits are defined in updated 

Table 1 and Table 2 in section 3.B of Rolls-Royce RB211-Trent 900 Alert Non 

Modification Service Bulletin (NMSB) 72-AF995 Revision 2.

Since issuance of EASA AD 2008-0202, Rolls-Royce plc has also introduced a 

new standard of HPT NGV’s with modification SB 72-G025 that increases the 

cooling flow of the aerofoils by increasing the cooling hole diameters. This 

modification will significantly reduce the risk of aerofoil cracking and material 

release therefore deleting the need for inspection beyond normal maintenance 

procedures. 

This AD supersedes EASA AD 2008-0202 by retaining the same requirements as 

in AD 2008-0202 except that: 

- Revised inspection limits provided in Rolls-Royce RB211-Trent 900 Alert 

NMSB 72-AF995 Revision 2 must be used. 

- Applicability is limited to Trent 900 engines which do not incorporate 

modification SB 72-G025. 

Effective Date: 19 March 2009

Required Action(s) 

and Compliance 

Time(s): 

Required as indicated, unless accomplished previously: 

Before accumulating 400 total cycles, inspect the HPT NGV Convex 

Surfaces, in accordance with the accomplishment instructions in section 3.A 

of Rolls-Royce RB211-Trent 900 Alert Non Modification Service Bulletin 

(NMSB) 72-AF995 Revision 2. 

If no damage is identified at first inspection: 

- repeat inspections must be carried out at intervals less than 250 Cycles 

apart. 

- if repeat inspections reveal no damage at 1000 cycles revert to normal 

inspection maintenance as detailed in the Rolls-Royce RB211-Trent 900 

Maintenance Planning Document (MPD). 

If any damage is identified: 

- refer to the Table 1 and Table 2 in section 3.B. of Rolls-Royce RB211-Trent 

900 Alert NMSB 72-AF995 Revision 2 for re-inspection intervals and rejection 

criteria.

Ref. Publications: Rolls-Royce RB211-Trent 900 NMSB 72-AF995 Revision 2, dated 09 

February 2009. 

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 required actions and the risk allowance have granted the issuance of 

a Final AD with Request for Comments, postponing the public 

consultation process after publication. 

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: Rolls-Royce plc., P.O. Box 31, Derby, DE24 

8BJ, United Kingdom; Telephone: +44 (0) 1332 242424, Fax: +44 (0) 

1332 249936; Email: tech.help@rolls-royce.com or download the 

publication from https://www.aeromanager.com