AD 95-08-06

This amendment adopts a new airworthiness directive (AD), applicable to certain Raytheon Corporate Jets Models DH/BH/HS/BAe 125-1A to -700A series, BAe 125-800A, and Hawker 800 series airplanes, that requires replacement of the existing standby static inverter with an inverter that incorporates a circuit board assembly sealed with a conformal coating. This amendment is prompted by reports of failure of the standby static inverter caused by electrical shorting from moisture condensing on the printed circuit boards (PCB), due to aberrations in the PCB conformal coating. The actions specified by this AD are intended to prevent malfunction of the standby static inverter due to exposure to moisture caused by inadequate insulation coating of the circuit board assembly. Malfunction or failure of the standby static inverter, when its use is necessary, could result in the loss of electric power for certain equipment critical to safety of flight.

Final rule.

95-08-06 RAYTHEON CORPORATE JETS, INC. (Formerly de Havilland; Hawker Siddeley; British Aerospace, plc): Amendment 39-9195. Docket 94-NM-220-AD.

Applicability: Model DH/BH/HS/BAe 125-1A to -700A series airplanes, inclusive, on which Modification 252740 has been installed; Model BAe 125-800A airplanes having constructor's numbers prior to number 258248; and Hawker 800 series airplanes; certificated in any category.

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 use the authority provided in paragraph (b) to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition; or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any airplane from the applicability of this AD.

Compliance: Required as indicated, unless accomplished previously.

To prevent an electrical short in the standby static inverter due to the printed circuit boards being exposed to condensed moisture, accomplish the following:

(a) Within 5 months of the effective date of this AD, remove the existing standby static inverter (type PC 250) and replace it with a Mod C Marathon/Flitetronics Inverter (type PC 250), in accordance with Raytheon Corporate Jets Hawker Service Bulletin SB.24-308-7673A, Revision 1, dated July 11, 1994.

(b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safetymay be used if approved by the Manager, Standardization Branch, FAA, Transport Airplane Directorate, ANM-113. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Standardization Branch, ANM-113.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Standardization Branch, ANM-113.

(c) 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.

(d) The replacement shall be done in accordance with Raytheon Corporate Jets Hawker Service Bulletin SB.24-308-7673A, Revision 1, dated July 11, 1994. 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 Corporate Jets, Inc., 3 Bishops Square, St. Albans Road West, Hatfield, Hertfordshire, AL109NE, United Kingdom. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(e) This amendment becomes effective on May 18, 1995.

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 Corporate Jets Models DH/BH/HS/BAe 125-1A to -700A series airplanes, BAe 125-800A airplanes, and Hawker 800 airplanes was published in the Federal Register on January 18, 1995 (60 FR 3592). That action proposed to require replacement of the existing standby static inverters with a printed circuit board assembly that is properly sealed with a conformal coating.

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.

For clarification purposes, the FAA has revised the references to the DH/BH/HS/BAe 125 models throughout this rule to add the model designator "A" to the series numbers. Models DH/BH/HS/BAe 125-1A through -700A are the models that are type certificated for operation in the United States and, accordingly, affected by this AD action.

After careful review of the available data, the FAA has determined that air safety and the public interest require the adoption of the rule with the clarifying change previously described. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD.

The FAA estimates that 450 airplanes of U.S. registry will be affected by this AD, that it will take approximately 4 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately $410 per airplane. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $292,500, or $650 per airplane.

The total cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of thisAD action, and that no operator would accomplish those actions in the future if this AD were not adopted.

The regulations adopted herein will not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

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 hasbeen 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."

List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment
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:

PART 39 - AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89.

39.13 - [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: