AD 97-09-05

This amendment adopts a new airworthiness directive (AD), applicable to all Raytheon Model BAe 125-1000A and Model Hawker 1000 series airplanes, that requires various modifications to increase the size of certain existing pressure venting areas and to add additional venting areas. This amendment is prompted by results of a design review of the requirements for certification of the cabin pressurization system. The actions specified by this AD are intended to prevent inadequate venting of cabin pressure in the event of rapid decompression, which could cause failure or deformation of certain structural members, and consequent reduced controllability of the airplane.

Final rule.

97-09-05 RAYTHEON AIRCRAFT COMPANY (Formerly Beech, Raytheon Corporate Jets, British Aerospace, Hawker Siddeley, et al): Amendment 39-10001. Docket 96-NM-180-AD.

Applicability: All Model BAe 125-1000A and Model Hawker 1000 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 otherwise 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 (b) 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.

NOTE 2: Raytheon Model BAe 125-1000B series airplanes are similar in design to the airplanes that are subject to the requirements of this AD and, therefore, also may be subject to the unsafe condition addressed by this AD. However, as of the effective date of this AD, those models are not type certificated for operation in the United States. Airworthiness authorities of countries in which Model BAe 125-1000B series airplanes are approved for operation should consider adopting corrective action, applicable to those models, that is similar to the corrective action required by this AD.

Compliance: Required as indicated, unless accomplished previously.

To prevent inadequate venting of cabin pressure in the event of rapid decompression, which could cause failure or deformation of certain structural members, and consequent reduced controllability of the airplane, accomplish the following:

(a) Within 8 months after the effective date of this AD, accomplish the requirements of paragraphs (a)(1), (a)(2), and (a)(3) of this AD.

NOTE 3: The manufacturer has advised that the modifications required by paragraph (a)(2) and (a)(3) of this AD should be incorporated concurrently.

(1) Install a pressure relief flap in the rear luggage compartment of the bulkhead at frame 19 (Modification No. 25A683C), in accordance with Raytheon Service Bulletin SB.21-151-25A683C, dated July 12, 1994.

(2) Enlarge two lightening holes, and add one new lightening hole in the rail web of the right-hand seat between frames 10B and 10D, and remove the fiberglass infill cover located outboard of the floor panels between frame 8 and frame 10B (Modification SB.253661B), in accordance with Raytheon Service Bulletin SB.53-81-3661B, dated February 25, 1994.

(3) Install two new vent holes in the underfloor diaphragm of frame 10D (Modification 253627A), in accordance with Raytheon Service Bulletin SB.53-76-3627A, dated February 25, 1994.

(b) 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, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate. 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 4: 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 actions shall be done in accordance with Raytheon Service Bulletin SB.21-151-25A683C, dated July 12, 1994; Raytheon Service Bulletin SB.53-81-3661B, dated February 25, 1994; and Raytheon Service Bulletin SB.53-76-3627A, dated February 25, 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 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 Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(e) This amendment becomes effective on May 30, 1997.

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 all Raytheon Model BAe 125-1000A and Model Hawker 1000 series airplanes was published in the Federal Register on February 12, 1997 (62 FR 6504). That action proposed to require:

1. installing a pressure relief flap in the rear luggage compartment of the bulkhead at frame 19;

2. enlarging two lightening holes and adding one new lightening hole in the rail web of the right seat between frames 10B and 10D, and removing fiberglass fill from the right support structure between frame 8 and frame 10B; and

3. installing two new vent holes in the underfloor diaphragm of frame 10D (right hand).

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
The FAA estimates that 31 Model BAe 125-1000A and Model Hawker 1000 series airplanes of U.S. registry will be affected by this AD, that it will take approximately 44 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $81,840, or $2,640 per airplane.

The cost impact figure discussed above is 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.

Regulatory Impact
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 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."

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. 106(g), 40113, 44701.

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