EASA AD No : 2009-0114 

EASA Form 110 Page 1/2 

EASA AIRWORTHINESS DIRECTIVE 

AD No.: 2009-0114 

Date: 28 May 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 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 : 

GE Aviation Systems Limited, trading as 

Dowty Propellers 

Type/Model designation(s) : 

R408/6-123-F/17 propellers 

TCDS Number: EASA.P.002 

Foreign AD : Not applicable 

Supersedure : None 

ATA 61 Propellers – Backplate Assembly – Sealant Application 

Manufacturer(s): Dowty Propellers 

Applicability: 

Model R408/6-123-F/17 propellers, all serial numbers (s/n). 

These propellers are known to be installed on, but not limited to, Bombardier 

DHC-8-400, DHC-8-401 and DHC-8-402 aeroplanes. 

Note: Transport Canada AD CF-2009-01, applicable to Bombardier DHC-8 

Series 400 aeroplanes, was issued on 19 January 2009 for the same unsafe 

condition that is addressed by this AD. 

Reason: 

Friction or contact between a propeller de-ice bus bar and the backplate 

assembly can cause failure of the bus bar and a consequent intermittent short 

circuit. Such a short circuit can cause a dual AC generator shutdown that, 

particularly in conjunction with an engine failure in icing conditions, could 

result in reduced controllability of the aeroplane. 

For the reason described above, this AD requires initial and repetitive 

application of sealant between the propeller bus bar assemblies and the 

backplate assembly. 

Effective Date: 11 June 2009 
EASA AD No : 2009-0114 

EASA Form 110 Page 2/2 

Required Action(s) 

and Compliance 

Time(s): 

Required as indicated, unless accomplished previously: 

(1) Within the next 5 000 flight hours (FH) after the effective date of this AD, 

apply sealant between the bus bar assemblies and the backplate 

assembly in accordance with the instructions of Dowty Propellers Alert 

Service Bulletin (ASB) D8400-61-66. 

(2) All affected Hub, Actuator and Backplate Assembly Line-Replaceable 

Units (LRU) with s/n DAP0347 and higher have received the initial 

sealant application prior to delivery/installation and are therefore already 

compliant with the requirement of paragraph (1) of this AD. 

(3) Prior to accumulating 10 000 FH after the initial sealant application and 

thereafter at intervals not to exceed 10 000 FH, re-apply sealant between 

the bus bar assemblies and the backplate assembly in accordance with 

the instructions of Dowty Propellers ASB D8400-61-66. 

(4) After modification of all propellers on an aeroplane as required by 

paragraph (1) of this AD, do not install any Dowty R408/6-123-F/17 

propeller on that aeroplane, unless sealant has been applied between the 

bus bar assemblies and the backplate assembly of that propeller in 

accordance with the requirements of this AD. 

Ref. Publications: 

Dowty Propellers ASB D8400-61-66 dated February 2007. 

The use of later approved revisions of this document is acceptable for 

compliance with 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: 

Dowty Propellers, Anson Business Park, Cheltenham Road East, 

Gloucester GL2 9QN, United Kingdom 

Tel +44 (0) 1452 716067 – Fax +44 (0) 1452 716001 

E-mail Mike.Towkan@ge.com