Airworthiness directives: Boeing; correction,
[Federal Register: December 13, 1999 (Volume 64, Number 238)]
[Rules and Regulations]
[Page 69392-69394]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr13de99-8]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
[Docket No. 98-NM-383-AD; Amendment 39-11175; AD 99-11-05]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; correction.
SUMMARY: This document corrects and clarifies information in an existing airworthiness directive (AD) that applies to all Boeing Model 737 series airplanes. That AD currently requires repetitive displacement tests of the secondary slide in the dual concentric servo valve of the power control unit (PCU) for the rudder, and replacement of the valve assembly with a modified valve assembly, if necessary. This document corrects certain PCU part and serial numbers and clarifies that PCU's with certain other serial numbers are not required to comply with the requirements of this AD. This correction is necessary to prevent failure of the secondary slide and consequent rudder hardover and reduced controllability of the airplane.
DATES: Effective June 28, 1999.
The incorporation by reference of certain publications, as listed in the regulations, was approved previously by the Director of the Federal Register as of June 28, 1999 (64 FR 27905, May 24, 1999).
FOR FURTHER INFORMATION CONTACT: R.C. Jones, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-1118; fax (425) 227-1181.
SUPPLEMENTARY INFORMATION: On May 13, 1999, the Federal Aviation Administration (FAA) issued AD 99-11-05, amendment 39-11175 (64 FR 27905, May 24, 1999), which applies to all Boeing Model 737 series airplanes. That AD requires repetitive displacement tests of the secondary slide in the dual concentric servo valve of the power control unit (PCU) for the rudder, and replacement of the valve assembly with a modified valve assembly, if necessary. That AD was prompted by reports of cracking found in PCU secondary servo valve slides. The actions specified by that AD are intended to prevent failure of the secondary slide and consequent rudder hardover and reduced controllability of the airplane.
Need for the Correction
Information received recently from the manufacturer indicates that the following clarifications and corrections are necessary. Paragraph (a)(2) of this AD was intended to address certain PCU's that are installed only after the effective date of the AD, and has been revised to clarify that intent. [Paragraph (a) of this AD already addresses
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airplanes on which these PCU's had been installed before the effective date.] As reflected in the applicable service bulletin referenced in this AD, paragraph (a)(2) also was intended to address the PCU's having part number 65C37053-(XX), but that reference was omitted from the final rule. Similarly, as reflected in the applicable service bulletin, paragraph (a)(3) was intended to address only identified airplanes that are equipped with certain PCU's. However, as adopted, the final rule was not so limited. [Airplanes having other PCU's are subject to the longer compliance time specified in paragraph (a)(4)]. The references to these part numbers have been added to this AD.
Finally, the FAA has revised paragraph (c) of this AD to more clearly specify the actuators that may be installed after the effective date of this AD. The FAA has determined that some PCU's (referenced in Boeing Alert Service Bulletin 737-27A1221, Revision 1, and Boeing Alert Service Bulletin 737-27A1222, Revision 1, both dated January 28, 1999) have been displacement tested, but have not been vibro engraved with the letter ``C.'' (Subsequent serial numbers greater than those specified in this AD are displacement tested as part of the certified production process, and are not vibro engraved.) The FAA has determined that, for PCU's having the specified serial numbers, only those that are vibro engraved with the letter ``C'' are in compliance with the requirements of this AD. Therefore, paragraph (c) of this AD has been corrected by removing the phrase ``or letters greater than `C'.''
Correction of Publication
This document corrects the error and correctly adds the AD as an amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 39.13).
The AD is reprinted in its entirety for the convenience of affected operators. The effective date of the AD remains June 28, 1999.
Since this action only corrects and clarifies the current requirements, it has no adverse economic impact and imposes no additional burden on any person. Therefore, the FAA has determined that notice and public procedures are unnecessary.
List of Subject in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Correction
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
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The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Corrected]
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Section 39.13 is amended by correctly adding the following airworthiness directive (AD):
99-11-05 Boeing: Amendment 39-11175. Docket 98-NM-383-AD.
Applicability: All Model 737 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 request approval for an alternative method of compliance in accordance with paragraph (e) 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 failure of the secondary servo valve slide in the rudder power control unit (PCU) due to cracking of the slide, and consequent rudder hardover and reduced controllability of the airplane, accomplish the following:
Displacement Testing
(a) Perform a displacement test of the secondary slide in the dual servo valve in the rudder PCU, in accordance with Boeing Alert Service Bulletin 737-27A1221, Revision 1, dated January 28, 1999 (for Model 737-100, -200, -300, -400, and -500 series airplanes); or 737-27A1222, Revision 1, dated January 28, 1999 (for Model 737-600, -700, and -800 series airplanes); at the applicable time specified by paragraph (a)(1), (a)(2), (a)(3), or (a)(4) of this AD. Repeat the displacement test on that PCU thereafter at intervals not to exceed 24,000 flight hours.
Note 2: Accomplishment of the initial displacement testing required by paragraph (a) of this AD in accordance with Boeing Alert Service Bulletin 737-27A1221, dated January 14, 1999 (for Model 737- 100, -200, -300, -400, and -500 series airplanes); or 737-27A1222, dated January 14, 1999 (for Model 737-600, -700, and -800, series airplanes) is acceptable only for the initial compliance requirements of this AD.
(1) For Model 737-100, -200, -300, -400, and -500 series airplanes: Conduct the displacement test within 16 months after the effective date of this AD.
(2) For airplanes on which a PCU specified in paragraph (a)(2)(I) or (a)(2)(ii) of this AD is installed within 16 months after the effective date of this AD: Conduct the displacement test within 16 months after the effective date of this AD.
(i) Part number 65-44861-12 and having serial number (S/N) 3509A or lower,
(ii) Part number 65C37053-(XX).
(3) For Model 737-600, -700, and -800 series airplanes having line numbers 1 through 222 inclusive that are equipped with PCU's having P/N 251A301-(XX) and serial number 299 or lower: Conduct the displacement test within 16 months after the effective date of this AD.
(4) For all other airplanes: Conduct the displacement test prior to the accumulation of 24,000 total flight hours on the PCU, or within 30 days after the effective date of this AD, whichever occurs later.
Corrective Actions
(b) If the results of the displacement test required by paragraph (a) of this AD are outside the limits specified by Boeing Alert Service Bulletin 737-27A1221, Revision 1, dated January 28, 1999 (for Model 737-100, -200, -300, -400, and -500 series airplanes), or 737-27A1222, Revision 1, dated January 28, 1999 (for Model 737-600, -700, and -800 series airplanes): Prior to further flight, accomplish the actions specified in paragraphs (b)(1) and (b)(2) of this AD.
(1) Replace the valve assembly, in accordance with the applicable alert service bulletin, with a serviceable valve assembly. And
(2) Following installation of the replacement valve assembly in accordance with paragraph (b)(1) of this AD, perform the displacement test required by paragraph (a) of this AD on that assembly, in accordance with the applicable alert service bulletin. If the test results are outside the limits specified by the applicable alert service bulletin, prior to further flight, replace the valve assembly with a serviceable valve assembly in accordance with the applicable alert service bulletin, and repeat the displacement test required by paragraph (a) of this AD on that assembly.
Note 3: Boeing Alert Service Bulletin 737-27A1222, Revision 1, dated January 28, 1999, refers to Parker Service Bulletin 381500-27- 01, dated December 22, 1998, as an additional source of service information for accomplishment of the displacement test for Model 737-600, -700, and -800 series airplanes.
(c) As of 16 months after the effective date of this AD, no person shall install a main rudder PCU specified in paragraph (c)(1) or (c)(2) of this AD unless that PCU's nameplate has been vibro- engraved with the letter ``C'' following the serial number. (Subsequent serial numbers greater than those listed below are displacement tested as part of the certified production process, and do not require the letter ``C'' to be vibro-engraved.)
(1) For Boeing Model 737-100, -200, -300, -400, and -500 series airplanes: A PCU having P/N 65-44861-12 and a serial number (S/N) 3509A or lower; or any PCU having P/N 65C37053-(XX).
(2) For Boeing Model 737-600, -700, and -800 series airplanes: A PCU having P/N 251A301-(X) and a S/N 0299 or lower.
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(d)(1) Within 30 days after accomplishing the initial displacement test required by paragraph (a) of this AD: Submit a report of the testing to the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; fax (425) 227-1181. The report must include the displacement testing results (both positive and negative findings), test data for any failed valve assemblies, a description of any discrepancies if found, the part number and serial number of each rudder PCU tested, and the airplane serial number.
(2) Within 30 days after accomplishing any repetitive displacement testing required by paragraph (a) of this AD: Submit a report of any failed valve assembly to the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; fax (425) 227- 1181. The report must include the displacement testing results of any failed valve assembly, test data for any failed valve assemblies, a description of any discrepancies found, the part number and serial number of each rudder PCU with a failed valve assembly, and the airplane serial number.
(3) Within 30 days after accomplishing the initial displacement test required by paragraph (a) of this AD: Submit failed valve assemblies for analysis to Parker Hannifin Corporation, Chief Engineer, Customer Support Operations, 16666 Von Karman Avenue, Irvine, California 92606.
(4) Information collection requirements contained in this regulation have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056.
Alternative Methods of Compliance
(e) 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, Seattle ACO. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO.
Note 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.
Special Flight Permits
(f) 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.
Incorporation by Reference
(g) The actions shall be done in accordance with Boeing Alert Service Bulletin 737-27A1221, Revision 1, dated January 28, 1999, or Boeing Alert Service Bulletin 737-27A1222, Revision 1, dated January 28, 1999. This incorporation by reference of those documents was previously approved by the Director of the Federal Register as of June 28, 1999 (64 FR 27905, May 24, 1999). Copies may be obtained from Boeing Commercial Airplane Group, P. O. Box 3707, Seattle, Washington 98124-2207. 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.
(h) The effective date of this amendment remains June 28, 1999.
Issued in Renton, Washington, on December 7, 1999. D.L. Riggin, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 99-32193Filed12-10-99; 8:45 am]
BILLING CODE 4910-13-P
