# AD 2000-02-35: Oxygen System Plumbing

- Type: Airworthiness directive
- Status: Current
- Products: Textron BAe.125 Series 1000A, BAe.125 Series 1000B, BAe.125 Series 800A, BAe.125 Series 800A (C-29A), BAe.125 Series 800B, BH.125 Series 400A, BH.125 Series 600A, DH.125 Series 1A, DH.125 Series 1A-522, DH.125 Series 1A/R-522, DH.125 Series 1A/S-522, DH.125 Series 3A and 27 more
- Effective: March 13, 2000
- Published: February 7, 2000, 65 FR 5749–5751
- Issued: January 28, 2000
- Issued as: Final rule
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Large airplane
- Amendment: 39-11553
- Docket: 99-NM-160-AD
- Registered aircraft: 151 may be affected, by airframe or engine model (OpenAirDocs)
- Official PDF: https://openairdocs.org/files/sha256/d8/b5/d8b56415a7835e627de219d04676666195fcb04bf23ad8afb2d930ee6d959a3f (from https://www.govinfo.gov/content/pkg/FR-2000-02-07/pdf/00-2410.pdf)
- Federal Register: https://www.federalregister.gov/documents/2000/02/07/00-2410/airworthiness-directives-raytheon-model-hawker-800-and-1000-airplanes-and-model-dh125-hs125-bh125
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/4D792A191A39593A86256A090075F4E5.0001
- DRS record last changed: January 21, 2026
- Page: https://openairdocs.org/ad/2000-02-35

## Summary

This amendment adopts a new airworthiness directive (AD), applicable to certain Raytheon Model Hawker 800 and 1000 airplanes and Model DH.125, HS.125, BH.125, and BAe.125 series airplanes, that requires replacement of cadmium plated fittings and cone caps in the oxygen system plumbing with improved fittings and cone caps, a detailed visual inspection of the oxygen system plumbing in the area of the replaced parts, and corrective actions, if necessary. This amendment is prompted by reports indicating that a field survey of the affected parts revealed that a reaction process was occurring, which resulted in cadmium flaking. The actions specified by this AD are intended to prevent flaking of cadmium from certain oxygen system plumbing fittings and cone caps from blocking the valves and impairing the function of the oxygen system, which could deprive the crew and passengers of necessary oxygen during an emergency that requires oxygen.

## The airworthiness directive

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

1. The authority citation for part 39 continues to read as follows:

2. Section 39.13 is amended by adding the following new airworthiness directive:

2000-02-35 Raytheon Aircraft Company (Formerly Beech): Amendment 39-11553. Docket 99-NM-160-AD.

Applicability: Models and series of airplanes as listed in the applicable service bulletin(s) specified in Table 1 of this AD, certificated in any category.

*Table 1*

| Model of Airplane | Raytheon Service Bulletin | Date of Service Bulletin |
| --- | --- | --- |
| DH.125, HS.125, BH.125 series 1A, 1B, 3A, 3B, 400A, 400B, 401B, 403A, 403B, 600A, 600B, 700A, and 700B airplanes | SB 35-3169 | September 1998. |
| BAe.125 series 800A (C-29A) airplanes | SB 35-3171 | September 1998. |
| BAe.125 series 800A and 800B airplanes, and Hawker 800 airplanes | SB 35-3034 and SB 35-3170 | September 1998. |
| BAe.125 series 1000A and 1000B airplanes, and Hawker 1000 airplanes | SB 35-3167 and SB 35-3168 | September 1998. |

Note 1:

This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (f) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent flaking of cadmium from certain oxygen system plumbing fittings and cone caps from blocking the valves and impairing the function of the oxygen system, which could deprive the crew and passengers of necessary oxygen during an emergency that requires oxygen, accomplish the following:

  (a) For Model DH.125, HS.125, BH.125 series 1A, 1B, 3A, 3B, 400A, 400B, 401B, 403A, 403B, 600A, 600B, 700A and 700B airplanes: Within 6 months after the effective date of this AD, 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 Raytheon Service Bulletin SB 35-3169, dated September 1998. If any flaking or corrosion is detected, prior to further flight, clean the tee-piece and sleeve, and perform an oxygen system flow check in accordance with the service bulletin. If any discrepancy is found during the flow check, prior to further flight, repair the oxygen system in accordance with the service bulletin, except as required by paragraph (e) of this AD.

Note 2:

For the purposes of this AD, 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.”

  (b) For Model BAe.125 series 800A (C-29A) airplanes: Within 6 months after the effective date of this AD, 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 Raytheon Service Bulletin SB 35-3171, dated September 1998. If any flaking or corrosion is detected, prior to further flight, clean the tee-piece and sleeve, and perform an oxygen system flow check in accordance with the service bulletin. If any discrepancy is found during the flow check, prior to further flight, repair the oxygen system in accordance with the service bulletin, except as required by paragraph (e) of this AD.

  (c) For Model BAe.125 series 800A and 800B airplanes and Model Hawker 800 airplanes: Within 6 months after the effective date of this AD, 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 Raytheon Service Bulletins SB 35-3034 or SB 35-3170, both dated September 1998, as applicable. If any flaking or corrosion is detected, prior to further flight, clean the tee-piece and sleeve, and perform an oxygen system flow check in accordance with the service bulletin. If any discrepancy is found during the flow check, prior to further flight, repair the oxygen system in accordance with the service bulletin, except as required by paragraph (e) of this AD.

  (d) For Model BAe.125 series 1000A and 1000B airplanes and Model Hawker 1000 series airplanes: Within 6 months after the effective date of this AD, 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 Raytheon Service Bulletin SB 35-3167 or SB 35-3168, both dated September 1998, as applicable. If any flaking or corrosion is detected, prior to further flight, clean the pipe connections, and perform an oxygen system flow check in accordance with the service bulletin. If any discrepancy is found during the flow check, prior to further flight, repair the oxygen system in accordance with the service bulletin, except as required by paragraph (e) of this AD.

  (e) If any discrepancy is found during a flow check required by paragraph (a), (b), (c), or (d) of this AD and the applicable service bulletin specifies to contact the manufacturer for a repair disposition, prior to further flight, repair the oxygen system in accordance with a method approved by the Manager, Wichita Aircraft Certification Office (ACO), FAA, Small Airplane Directorate.

### (f) Alternative Methods of Compliance

  (f) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Wichita ACO. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Wichita ACO.

Note 3:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Wichita ACO.

### (g) Special Flight Permits

  (g) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

### (h) Incorporation by Reference

  (h) Except as provided by paragraph (e) of this AD, the actions shall be done in accordance with Raytheon Service Bulletin SB 35-3169, dated September 1998; Raytheon Service Bulletin SB 35-3171, dated September 1998; Raytheon Service Bulletin SB 35-3034, dated September 1998; Raytheon Service Bulletin SB 35-3170, dated September 1998; Raytheon Service Bulletin SB 35-3167, dated September 1998; or Raytheon Service Bulletin SB 35-3168, dated September 1998; as applicable. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Raytheon Aircraft Company, Manager Service Engineering, Hawker Customer Support Department, P.O. Box 85, Wichita, Kansas 67201-0085. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Small Airplane Directorate, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

    (i) This amendment becomes effective on March 13, 2000.

## Rule preamble

### Dates

Effective March 13, 2000.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of March 13, 2000.

### Addresses

The service information referenced in this AD may be obtained from Raytheon Aircraft Company, Manager Service Engineering, Hawker Customer Support Department, P.O. Box 85, Wichita, Kansas 67201-0085.

This information may be examined at:

### For further information contact

Paul C. DeVore, Aerospace Engineer, Systems and Propulsion Branch, ACE-116W, FAA, Small Airplane Directorate, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas 67209; telephone (316) 946-4142; fax (316) 946-4407.

### SUPPLEMENTARY INFORMATION

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Raytheon Model Hawker 800 and 1000 airplanes and Model DH.125, HS.125, BH.125, and BAe.12 series airplanes was published in the Federal Register on November 16, 1999 (64 FR 62129). That action proposed to require replacement of cadmium plated fittings and cone caps in the oxygen system plumbing with improved fittings and cone caps, a detailed visual inspection of the oxygen system plumbing in the area of the replaced parts, and corrective actions, if necessary.

### Comments

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were submitted in response to the proposal or the FAA's determination of the cost to the public.

### Conclusion

The FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

### Cost Impact

There are approximately 724 airplanes of the affected design in the worldwide fleet. The FAA estimates that 481 airplanes of U.S. registry will be affected by this AD.

For Model DH.125, HS.125, BH.125 series 1A/1B, 3A/3B, 400A, 400B, 401B, 403A, 403B, 600A, 600B, 700A, 700B airplanes (236 airplanes of U.S. registry), it will take approximately 7 work hours per airplane to accomplish the required actions, at an average labor rate of $60 per work hour. Required parts will cost approximately between $28 and $79 per airplane. Based on these figures, the cost impact of the AD on U.S. operators of these airplanes is estimated to be between $105,728, and $117,764, or between $448 and $499 per airplane.

For Model BAe.125 series 800A (C-29A) airplanes (6 airplanes of U.S. registry), it will take approximately 3 work hours per airplane to accomplish the required actions, at an average labor rate of $60 per work hour. Required parts will cost approximately $61 per airplane. Based on these figures, the cost impact of the AD on U.S. operators of these airplanes is estimated to be $1,446, or $241 per airplane.

For Model BAe.125 series 800A, and 800B airplanes, and Model Hawker 800 airplanes (202 airplanes of U.S. registry), it will take approximately 10 work hours per airplane to accomplish the required actions, at an average labor rate of $60 per work hour. Required parts will cost approximately between $16 and $22 per airplane. Based on these figures, the cost impact of the AD on U.S. operators of these airplanes is estimated to be between $124,432 and $125,644, or between $616 and $622 per airplane.

For Model BAe.125 series 1000A and 1000B airplanes, and Model Hawker 1000 airplanes (37 airplanes of U.S. registry), it will take approximately 6 work hours per airplane to accomplish the required actions, at an average labor rate of $60 per work hour. Required parts will cost approximately between $66 and $122 per airplane. Based on these figures, the cost impact of the AD on U.S. operators of these airplanes is estimated to be between $15,762 and $17,834, or between $426 and $482 per airplane.

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. However, the FAA has been advised that manufacturer warranty remedies are available for some labor costs associated with accomplishing the actions required by this AD. Therefore, the future economic cost impact of this rule on U.S. operators may be less than the cost impact figures indicated above.

### Regulatory Impact

The regulations adopted herein will not have a substantial direct effect on the States, on the relationship between the national Government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this action (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption ADDRESSES.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS A3EU](https://openairdocs.org/tcds/A3EU): Textron Aviation Inc.; names 37 of 50 models: BAe.125 Series 1000A, HS.125 Series 3B/RB, HS.125 Series 401B, HS.125 Series 600A, HS.125 Series 600B/2, HS.125 Series 403A(C), HS.125 Series 600B/1, HS.125 Series 700A…

## Registered aircraft it may apply to (OpenAirDocs)

Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment.

- Aircraft: 151 (151 by airframe model, 0 by engine model)
- Makers: British Aerospace 89, Raytheon Corporate Jets 29, Corporate Jets 17, Hawker Siddeley 11, Raytheon 4, Hawker Beechcraft 1

Models with the most aircraft:

- [British Aerospace BAE 125 SERIES 800A](https://openairdocs.org/model/british-aerospace-bae-125-series-800a): 61 aircraft (airframe model)
- [British Aerospace HS 125-700A](https://openairdocs.org/model/british-aerospace-hs-125-700a): 14 aircraft (airframe model)
- [British Aerospace BAE 125 SERIES 1000A](https://openairdocs.org/model/british-aerospace-bae-125-series-1000a): 9 aircraft (airframe model)
- [Raytheon Corporate Jets HAWKER 800](https://openairdocs.org/model/raytheon-corporate-jets-hawker-800): 9 aircraft (airframe model)
- [Corporate Jets BAE 125-1000A](https://openairdocs.org/model/corporate-jets-bae-125-1000a): 9 aircraft (airframe model)
- [Corporate Jets BAE 125-800A](https://openairdocs.org/model/corporate-jets-bae-125-800a): 8 aircraft (airframe model)
- [Raytheon Corporate Jets BAE 125-800A](https://openairdocs.org/model/raytheon-corporate-jets-bae-125-800a): 8 aircraft (airframe model)
- [Raytheon Corporate Jets HAWKER 1000](https://openairdocs.org/model/raytheon-corporate-jets-hawker-1000): 8 aircraft (airframe model)
- [Hawker Siddeley HS.125 SERIES 700A](https://openairdocs.org/model/hawker-siddeley-hs-125-series-700a): 7 aircraft (airframe model)
- [British Aerospace BAE 125-800A](https://openairdocs.org/model/british-aerospace-bae-125-800a): 5 aircraft (airframe model)
- [Raytheon Corporate Jets BAE 125-1000A](https://openairdocs.org/model/raytheon-corporate-jets-bae-125-1000a): 4 aircraft (airframe model)
- [Hawker Siddeley BH.125-400A](https://openairdocs.org/model/hawker-siddeley-bh-125-400a): 2 aircraft (airframe model)
- [Hawker Siddeley DH.125-3A/RA](https://openairdocs.org/model/hawker-siddeley-dh-125-3a-ra): 2 aircraft (airframe model)
- [Raytheon BAE 125-800A](https://openairdocs.org/model/raytheon-bae-125-800a): 2 aircraft (airframe model)
- [Raytheon HAWKER 1000](https://openairdocs.org/model/raytheon-hawker-1000): 1 aircraft (airframe model)
- [Hawker Beechcraft BAE 125-800B](https://openairdocs.org/model/hawker-beechcraft-bae-125-800b): 1 aircraft (airframe model)
- [Raytheon HS 125-700A](https://openairdocs.org/model/raytheon-hs-125-700a): 1 aircraft (airframe model)

All 19 models: https://openairdocs.org/ad/2000-02-35/models.md
Every aircraft: https://openairdocs.org/ad/2000-02-35/aircraft.md

## Related documents

- [Proposed rule 99-NM-160-AD](https://openairdocs.org/proposed/99-NM-160-AD): Notice of proposed rulemaking (NPRM), published Nov 16, 1999

Its text cites no advisory circulars or STCs.

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