EASA AD No: 2012-0040

EASA Form 110 Page 1/2 

## EASA AIRWORTHINESS DIRECTIVE

AD No.: 2012-0040

Date: 13 March 2012

Note: This Airworthiness Directive (AD) is issued b y EASA, acting in accordance with Regulation (EC) No 216/2008 on behalf of the European Communit y, its Member States and of the European third countries that participate in the ac tivities 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 en sured by accomplishing any applicable ADs. Conseque ntly, no person may operate an aircraft to which an AD applies, except in accordan ce with the requirements of that AD, unless otherwi se 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, A rticle 14(4) exemption].


### Type Approval Holder’s Name :
BAE SYSTEMS (OPERATIONS) LTD Type/Model designation(s) :
BAe 146 and AVRO 146-RJ aeroplanes

TCDS Number: EASA.A.182

Foreign AD: Not applicable

Supersedure: None



### ATA 24 Electrical Power – Ceramic Terminal Blocks – Inspec tion / Replacement

Manufacturer(s): BAE Systems (Operations) Ltd, Brit ish Aerospace plc, British Aerospace (Commercial Aircraft) Ltd, British Aerospace (Opera tions) Ltd, British Aerospace Regional Aircraft Ltd, British Aerospace Regional A ircraft trading as Avro International Aerospace.

Applicability: BAe 146 and AVRO 146-RJ series aerop lanes, all models, all serial numbers.

Reason: Moisture ingress has been discovered on cer tain ceramic terminal blocks, mounted on the engine cowlings, through which the w iring for the engine fire extinguishers, fire detection circuits and engine a nd intake anti ice system are routed. The affected terminal blocks were introduce d through BAE Systems SB 71-077-01693A ( modification HCM01693A) during the period 2002-2004 , as this modification was mandated by CAA UK AD 005-10-2001. Moisture ingress has a detrimental effect on the insulation resistance o f the ceramic terminal block with the resultant possibility of interconnections between all terminals. Most of the possible failure conditions in the terminal blo ck should result in an evident warning or other indication. However, the functiona l loss of the number 2 fire bottle would be a dormant failure.
This condition, if not corrected, could result in t he failure of a fire bottle to discharge when activated, possibly preventing the f light crew in extinguishing an engine fire.
For the reasons described above, this AD requires a one-time inspection of the ceramic terminal blocks to determine the insulation resistance and, depending on findings, replacement of terminal blocks, and th e reporting of the results to the BAE Systems. These will be used to establish a suitable repetitive inspection interval, which is expected to be introd uced through the Maintenance Review Board (MRB) process.EASA AD No: 2012-0040

EASA Form 110 Page 2/2 Effective Date: 27 March 2012

Required Action(s) and Compliance Time(s): Required as indicated, unless accomplished previous ly: (1) Within 4 000 flight cycles or 18 months, whiche ver occurs first after the effective date of this AD, conduct an insulation re sistance test on each terminal block in accordance with the accomplishmen t instructions, paragraphs 2.C, 2.D, 2.E and 2.F, of BAE Systems (O perations) Ltd Inspection Service Bulletin (ISB) 24-143 (the ISB). (2) If, during the inspection as required by paragr aph (1) of this AD, any defective terminal block is identified, before next flight, replace it with a serviceable terminal block. (3) Within 30 days after the inspection as required by paragraph (1) of this AD, complete the test result sheets in Appendices 1, 2, 3 and 4 and the inspection report in Appendix 6 of the ISB and send this to BAE Systems (Operations) Ltd in accordance with the instruction s of paragraph 2.I of the ISB.

Ref. Publications: BAE Systems (Operations) Limited ISB.24-143 dated 2 6 September 2011. The use of later approved revisions of this documen t is acceptable for compliance with the requirements of this AD.

Remarks : 1. If requested and appropriately substantiated, EA SA can approve Alternative Methods of Compliance for this AD.
2. This AD was posted on 07 February 2012 as PAD 12 -008 for consultation until 06 March 2012. No comments were received duri ng the consultation period. 3. Enquiries regarding this AD should be referred t o the Safety Information Section, Executive Directorate, EASA. E-mail ADs@easa.europa.eu

. 4. For any question concerning the technical conten t of the requirements in this AD, please contact: BAE Systems (Operations) Ltd, Customer Information Department, Prestwick International Airport, Ayrshire, KA9 2RW, Scotland, The United Kingdom; Telephone +44 1292 675207, Facsimile +44 1 292 675704; E-mail: RApublications@baesystems.com

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