AD 95-22-08

This amendment supersedes an existing airworthiness directive (AD), applicable to certain British Aerospace Model Viscount 744, 745D, and 810 airplanes, that currently establishes time-in-service limits for components of the fuselage pressure vessel, and requires modifications and inspections of various fuselage components to assure the continued structural integrity of these airplanes through the manufacturer's design life goal. This amendment requires additional modifications and inspections of the fuselage pressure vessel to extend the fuselage pressure vessel life from 30 to 45 years since new. This amendment is prompted by results of a review of fatigue test findings, stress analysis, and in-service history associated with pressure vessel components. The actions specified by this AD are intended to prevent reduced structural capability of the fuselage pressure vessel.

Final rule

95-22-08 BRITISH AEROSPACE REGIONAL AIRCRAFT LIMITED (Formerly British Aerospace Commercial Aircraft Limited, Vickers-Armstrongs Aircraft Limited): Amendment 39-9416. Docket 94-NM-135-AD. Supersedes AD 65-20-04, Amendment 39-3138.
Applicability: All Model Viscount 744, 745D, and 810 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 (d) of this AD 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 requestshould 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 reduced structural capability of the fuselage pressure vessel, accomplish the following:

(a) To operate the airplane for a maximum of 30 years since the date of manufacture or 75,000 total landings, whichever occurs first, accomplish the following:

(1) Perform visual, eddy current, dye penetrant, and x-ray inspections in accordance with Sections 2 through 10 of British Aerospace Preliminary Technical Leaflet (PTL) No. 221, Issue 10, dated May 1, 1994 (for Model Viscount 744 and 745D airplanes); or PTL No. 94, Issue 10, dated September 1, 1993 (for Model Viscount 810 airplanes); as applicable. Perform the initial inspection at the later of the times specified in paragraphs (a)(1)(i) and (a)(2)(ii) of this AD. Thereafter, repeat these inspections at the repetitive intervals specified in the applicable PTL.

(i) Prior to the threshold specified in Sections 2 through 10 of the applicable PTL; or within the next repetitive inspection specified in Sections 2 through 10 of the applicable PTL following the immediately preceding inspection accomplished in accordance with PTL No. 221, Issue 4 (for Model Viscount 744 and 745D airplanes), or PTL No. 94, Issue 4 (for Model Viscount 810 airplanes); whichever occurs first. Or

(ii) Within 60 days after the effective date of this AD.

(2) Install the modifications specified in Sections 2 through 10 of British Aerospace PTL No. 221, Issue 10, dated May 1, 1994 (for Model Viscount 744 and 745D airplanes); or PTL No. 94, Issue 10, dated September 1, 1993 (for Model Viscount 810 airplanes); as applicable. Accomplish this installation at the later of the times specified in paragraphs (a)(2)(i) and (a)(2)(ii) of this AD.

(i) Prior to the accumulation of the number of equivalent flights at 6.5 pounds per square inch (psi) specified in the initial compliance columns of Sections 2 through 10 of the applicable PTL. Or

(ii) Within 60 days after the effective date of this AD.

NOTE 2: The number of equivalent flights at 6.5 psi is determined by using the procedure specified in Section 1, Part 6, Paragraph 6.6, of PTL No. 221 or PTL No. 94, as applicable.

(3) Modify the components of the pressurization system to reduce the cabin pressure maximum pressure setting to 3.5 psi, in accordance with Section 1, Part 7, Paragraph 7.5.2 of British Aerospace PTL No. 221, Issue 10, dated May 1, 1994 (for Model Viscount 744 and 745D airplanes); or PTL No. 94, Issue 10, dated September 1, 1993 (for Model Viscount 810 airplanes); as applicable. Accomplish this modification at the later of the times specified in paragraphs (a)(3)(i) and (a)(3)(ii) of thisAD.

(i) Prior to the accumulation of 25 years since date of manufacture, or prior to the accumulation of the number of flights equivalent to 17,000 flights at 6.5 psi; whichever occurs first. Or

(ii) Within 30 days after the effective date of this AD.

(b) This paragraph is applicable only to airplanes listed in British Aerospace PTL No. 320, Issue 3, dated October 1, 1993 (for Model Viscount 744 and 745 D airplanes); and PTL No. 189, Issue 5, dated May 1, 1994 (for Model Viscount 810 airplanes). To operate the airplane for a maximum of 45 years since date of manufacture or 75,000 total landings, whichever occurs first: Prior to the accumulation of 30 years since date of manufacture, or within 2 months after the effective date of this AD, whichever occurs later, perform the inspections, change the inspection times, install the modifications, and perform all other actions specified in the applicable PTL.

(c) If any crack(s) or corrosion is found during any inspection required by this AD, prior to further flight, repair in accordance with British Aerospace PTL No. 221, Issue 10, dated May 1, 1994 (for Model 744 and 745D airplanes), or PTL No. 94, Issue 10, dated September 1, 1993 (for Model 810 airplanes).

(d) 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 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Standardization Branch, ANM-113.

(e) 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.

(f) This amendment becomes effective on November 27, 1995.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 65-20-04, amendment 39-3138 (23 FR 5506, February 9, 1978), which is applicable to certain British Aerospace Model Viscount 744, 745D, and 810 airplanes, was published in the Federal Register on May 9, 1995 (60 FR 24587). The action proposed to require various modifications and inspections of the fuselage pressure vessel to extend the fuselage pressure vessel life from 30 to 45 years since new.

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

There are approximately 29 Model Viscount 744, 745D, and 810 series airplanes of U.S. registry will be affected by this AD.

The actionsthat are currently required by AD 65-20-04 take approximately 200 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts cost approximately $37,000 per airplane. Based on these figures, the total cost impact on U.S. operators of the actions required by AD 65-20-04 is estimated to be $1,421,000, or $49,000 per airplane.

The new actions that are required by this new AD will take approximately 400 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts will cost approximately $37,400 per airplane. Based on these figures, the total cost impact on U.S. operators of the new requirements of this AD is estimated to be $1,780,600, or $61,400 per airplane.

The total 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.

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, 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 USC 106(g), 40101, 40113, 44701.

39.13 - [Amended]
2. Section 39.13 is amended by removing amendment 39-3138 (23 FR 5506, February 9, 1978), and by adding a new airworthiness directive (AD), amendment 39-9416, to read as follows: