AIRWORTHINESS DIRECTIVE
On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/HS 125/161 and issues the following AD under subregulation 39.001(1) of CASR 1998.  The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.
British Aerospace BAe 125 Series Aeroplanes
AD/HS 125/161 Amdt 1
Oxygen System
19/2013
 
Applicability:
Models and series of aeroplanes as listed in the applicable Raytheon Aircraft Service Bulletin(s) (SB) specified in the following table:

 

Model of Aeroplane
SB No
SB Date

DH.125, HS.125, BH.125 series 1A, 1B, 3A, 3B, 400A, 400B, 401B, 403A,403B, 600A, 600B, 700A, and 700B
SB 35-3169
September 1998

BAe.125 series 800A (C-29A)
SB 35-3171
September 1998

BAe.125 series 800A, 800B, and Hawker 800
SB 35-3034 and
SB 35-3170
September 1998

BAe.125 series 1000A, 1000B, and Hawker 1000
SB 35-3167 and
SB 35-3168
September 1998


Requirement:
1.    For Model DH.125, HS.125, BH.125 series 1A, 1B, 3A, 3B, 400A, 400B, 401B, 403A, 403B, 600A, 600B, 700A and 700B aeroplanes:
a.     Replace the cadmium plated cone caps in the oxygen system plumbing with improved cone caps, and perform a detailed visual inspection of the removed cone caps, tee-piece and sleeve for evidence of flaking or corrosion; in accordance with SB 35-3169 dated September 1998.
b.    If any flaking or corrosion is detected, clean the tee-piece and sleeve, and perform an oxygen system flow check in accordance with the SB.
c.     If any discrepancy is found during the flow check, repair the oxygen system in accordance with the SB, except as required by Requirement 5.

 
 
 
 
2.    For Model BAe.125 series 800A (C-29A) aeroplanes:
a.     Replace the cadmium plated cone caps in the oxygen system plumbing with improved cone caps, and perform a detailed visual inspection of the removed cone caps, tee-piece and sleeve for evidence of flaking or corrosion; in accordance with SB 35-3171, dated September 1998.
b.    If any flaking or corrosion is detected, clean the tee-piece and sleeve, and perform an oxygen system flow check in accordance with the SB.
c.     If any discrepancy is found during the flow check, repair the oxygen system in accordance with the SB, except as required by Requirement 5.
3.    For Model BAe.125 series 800A and 800B aeroplanes and Model Hawker 800 aeroplanes:
Replace the cadmium plated cone caps in the oxygen system plumbing with improved cone caps, and perform a detailed visual inspection of the removed cone caps, tee-piece and sleeve for evidence of flaking or corrosion; in accordance with SB 35-3034 or SB 35-3170, both dated September 1998, as applicable.
b.    If any flaking or corrosion is detected, clean the tee-piece and sleeve, and perform an oxygen system flow check in accordance with the SB.
c.     If any discrepancy is found during the flow check, repair the oxygen system in accordance with the SB, except as required by Requirement 5.
4.    For Model BAe.125 series 1000A and 1000B aeroplanes and Model Hawker series aeroplanes:
a.     Replace the cadmium plated fittings in the oxygen system plumbing with improved fittings, and perform a detailed visual inspection of the removed fittings and the pipe connections for evidence of flaking or corrosion; in accordance with SB 35-3167 or SB 35-3168, both dated September 1998, as applicable.
b.    If any flaking or corrosion is detected, clean the pipe connections, and perform an oxygen system flow check in accordance with the SB.
c.     If any discrepancy is found during the flow check, repair the oxygen system in accordance with the SB, except as required by Requirement 5.
5.    If any discrepancy is found during a flow check required by Requirements 1, 2, 3 or 4 and the applicable SB specifies to contact the manufacturer for a repair disposition, repair the oxygen system in accordance with a method approved by the Manager, Technical Specialists Section, Certification Standards Branch, Civil Aviation Safety Authority, GPO Box 2005 Canberra ACT 2601, Facsimile
(02) 6217 1914.

 
Note 1:  For the purposes of this Directive, a detailed visual inspection is defined as: "An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity.  Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector.  Inspection aids such as mirror, magnifying lenses, etc., may be used.  Surface cleaning and elaborate access procedures may be required."
Note 2:  FAA AD 2000-02-35 Amdt 39-11553 refers.

Compliance:
For Requirement 1.a. - Within 6 months after the effective date of this Directive.
For Requirement 1.b. - Before further flight.
For Requirement 1.c. - Before further flight.
For Requirement 2.a. - Within 6 months after the effective date of this Directive.
For Requirement 2.b. - Before further flight.
For Requirement 2.c. - Before further flight.
For Requirement 3.a. - Within 6 months after the effective date of this Directive.
For Requirement 3.b. - Before further flight.
For Requirement 3.c. - Before further flight.
For Requirement 4.a. - Within 6 months after the effective date of this Directive.
For Requirement 4.b. - Before further flight.
For Requirement 4.c. - Before further flight.
For Requirement 5 - Before further flight.

 
The effective date of this Amendment is 10 September 2013.

Background:
Amendment 1 is issued to correct typographical error in Note 2 of the Requirement Section.  The FAA AD reference is corrected from 2000-03-35 to 2000-02-35.
The Federal Aviation Administration has advised that Raytheon received reports indicating that a field survey revealed that a reaction process was occurring, which resulted in cadmium flaking.  The flaking could cause blocking of valves resulting in impairing the function of the oxygen system, which could deprive the crew and passengers of necessary oxygen during an emergency that requires oxygen.
This Directive specifies actions designed to prevent flaking of cadmium from certain oxygen system plumbing fittings and cone caps from blocking the valves.

 
 
There is no change to initial requirements of the AD.
The original issue of this Airworthiness Directive became effective on
23 March 2000.

Mike Higgins
Delegate of the Civil Aviation Safety Authority
5 September 2013