Source: https://www.federalregister.gov/documents/2011/11/28/2011-30582/airworthiness-directives-the-boeing-company-airplanes
Timestamp: 2017-10-24 12:21:32
Document Index: 642961789

Matched Legal Cases: ['art 2', 'art 3', 'art 3', 'art 6', 'art 6', 'art 3', 'art 3', 'art 4', 'art 4', 'art 6', 'art 5', 'art 5', 'art 5', 'art 6', 'art 6', 'art 6', 'art 1']

76 FR 72863
72863-72866 (4 pages)
Flight Cycle Counting Procedure
Determine Material of the Components of the Horizontal Stabilizer
Repetitive Inspections of 7075 Aluminum Components
Repetitive Inspections of 7079 Aluminum Components
Modification/Chord Replacement
Supplemental Structural Inspection Document Inspections
https://www.federalregister.gov/d/2011-30582 https://www.federalregister.gov/d/2011-30582
We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 707-100 long body, -200, -100B long body, and -100B short body series airplanes; Model 707-300, -300B, -300C, and -400 series airplanes; and Model 720 and 720B series airplanes. For certain airplanes, this proposed AD would require using redefined flight cycle counts, determining the type of material of the horizontal stabilizer, rear spar, upper chords, and lower chords on the inboard and outboard ends of the rear spar; repetitively inspecting for cracking of the horizontal stabilizer components; and repairing or replacing the chord, or modification of chord segments made from 7079 aluminum, if necessary. For all airplanes, this proposed AD would require inspecting certain structurally significant items, and repairing discrepancies if necessary. This proposed AD was prompted by reports of stress corrosion cracking in the chord segments made from 7079 aluminum in the horizontal stabilizer rear spar, and fatigue cracking in the chord segments made from 7075 aluminum. We are proposing this AD to detect and correct stress corrosion and/or fatigue cracking in the horizontal stabilizer, which could compromise the structural integrity of the stabilizer.
Berhane Alazar, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office (ACO), 1601 Lind Avenue SW., Renton, Washington 98057-3356; phone: (425) 917-6577; fax: (425) 917-6590, email: berhane.alazar@faa.gov.
We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2011-1250; Directorate Identifier 2010-NM-031-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD because of those comments.
We have received numerous reports of stress corrosion cracking in the chord segments made from 7079 aluminum in the Model 707 horizontal stabilizer rear spar. 7079 aluminum is known to be susceptible to stress corrosion cracking. Development of stress corrosion cracking was slowed by the accomplishment of the actions specified in Boeing 707 Service Bulletin 3356, Revision 2, dated December 12, 1991; and Boeing 707 Service Bulletin 3381, Revision 2, dated January 31, 1991.
In addition, we have received three reports of fatigue cracking in the upper chords of the horizontal stabilizer rear spar near the side of the body. These chords are made from 7075 aluminum. In all three cases, the actions specified in Boeing 707/720 Service Bulletin A3313, Revision 1, dated May 27, 1977, had been incorporated. The fatigue cracking in either 7075 or 7079 material configuration has occurred early in the life of the modified structure. The fatigue cracks were generated by frequent training flights that included multiple touch-and-go cycles, which are most prevalent with military operators. These conditions, if not corrected, could result in stress corrosion and/or fatigue cracking in the horizontal stabilizer, which could compromise the structural integrity of the stabilizer.
Parts made from 7079 aluminum have also been discovered on airplanes that were not originally delivered with those parts. Therefore, to adequately address the stress corrosion cracking in the chord segments in the rear spar of the horizontal stabilizer, it is necessary to determine the chord configuration on the airplane. Furthermore, it is also necessary to carefully maintain a record of that configuration until all chord segments of the rear spar of the horizontal stabilizers that are made from 7079 aluminum have been removed from the fleet. Since horizontal stabilizers can be swapped, it is also necessary to implement the inspections for early fatigue cracking on all airplanes, regardless of their current usage.
We have reviewed Boeing 707 Alert Service Bulletin A3515, dated December Start Printed Page 7286419, 2007 (for Model 707 airplanes); and Boeing 707 Alert Service Bulletin A3516, dated April 4, 2008 (for Model 707 airplanes, and Model 720 and 720B series airplanes).
Boeing 707 Alert Service Bulletin A3515 describes procedures for the following actions:
Counting flight-cycles to determine the compliance times.
Determining the type of material of the horizontal stabilizer, rear spar, upper chords, and lower chords on the inboard and outboard ends of the rear spar.
Repetitive special detailed inspections for cracking of the upper chord on the inboard end of the rear spar of the left and right side horizontal stabilizers.
Repetitive high frequency eddy current inspections for cracking of the web flanges of the upper and lower chords of the rear spar of the left and right side horizontal stabilizers between stabilizer stations 92.55 and 272.55 for 7079 aluminum components.
Repetitive low frequency eddy current inspections for cracking of the forward skin flanges of the upper and lower chords of the rear spar in the left and right side horizontal stabilizers from stabilizer stations -13.179 to 272.55 (for lower chords) and 92.55 to 272.55 (for upper chords) for 7079 aluminum components.
Repetitive special detailed inspections for cracking of the upper chord of the inboard side of the rear spar in the left and right side horizontal stabilizers from stabilizer station -13.179 to 92.55 for 7079 aluminum components.
Replacing certain chord components made from 7079 aluminum.
Corrective actions, including replacing the chord(s) with a new chord and contacting Boeing for repair instructions and doing the repair.
Boeing 707 Alert Service Bulletin A3516 specifies one-time inspections of certain structurally significant items, and provides procedures for counting flight cycles for determining the compliance times for the inspections.
We issued AD 85-12-01, Amendment 39-5073 (50 FR 26690, June 28, 1985), for Model 707 and 720 airplanes, as revised (AD 85-12-01 R1, Amendment 39-5439 (51 FR 36002, October 8, 1986). That AD requires structural inspections and repairs or replacement on certain high time airplanes that have exceeded their fatigue design life.
We are proposing this AD because we evaluated all relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of these same type designs. This proposed AD would require accomplishing the actions specified in the service information described previously, except as discussed below. The requirements of this proposed AD do not affect the requirements of AD 85-12-01 R1, Amendment 39-5439 (51 FR 36002, October 8, 1986).
Paragraph (i) of this proposed AD specifies determining the material of the structural components of the horizontal stabilizer in accordance with Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007. That service bulletin also specifies that this action be repeated. We have determined that accomplishing this action one time only will provide an adequate level of safety, provided that the component material is determined before further flight on any replaced horizontal stabilizer.
Paragraph (i) of this proposed AD specifies a special detailed inspection of the upper chords, in accordance with Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007. That service bulletin specifies a compliance time of 180 days or 500 flight cycles (after the date on the service bulletin). This proposed AD, however, would remove the 500-flight-cycle compliance time to ensure that no airplane is unintentionally grounded, because it is possible an operator might exceed the flight-cycle grace period specified in paragraph (i) of this proposed AD before completing the inspection for chord material specified in paragraph (h) of this proposed AD. Similarly, paragraph (k) of this proposed AD removes the 250- and 1000-flight-cycle compliance times (specified in Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007) for the initial inspection. This proposed AD would require these inspections within 180 days after the effective date of the AD.
Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007, specifies to contact the manufacturer for instructions on how to repair certain conditions, but this proposed AD would require repairing those conditions in one of the following ways:
We estimate that this proposed AD would affect 10 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.
We are issuing this rulemaking under the authority described in “Subtitle VII, Part A, Subpart III, Section 44701: General requirements.” Under that Start Printed Page 72865section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.
The Boeing Company: Docket No. FAA-2011-1250; Directorate Identifier 2010-NM-031-AD.
(b) This AD affects AD 85-12-01, Amendment 39-5073 (50 FR 26690, June 28, 1985), as revised by AD 85-12-01 R1, Amendment 39-5439, (51 FR 36002, October 8, 1986).
(c) This AD applies to The Boeing Company Model 707-100 long body, -200, -100B long body, and -100B short body series airplanes; Model 707-300, -300B, -300C, and -400 series airplanes; and Model 720 and 720B series airplanes; certificated in any category; as identified in Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007, and Boeing 707 Alert Service Bulletin A3516, dated April 4, 2008.
(e) This AD was prompted by reports of stress corrosion cracking in the chord segments made from 7079 aluminum in the horizontal stabilizer rear spar, and fatigue cracking in the chord segments made from 7075 aluminum. The Federal Aviation Administration is issuing this AD to detect and correct stress corrosion and/or fatigue cracking in the horizontal stabilizer, which could compromise the structural integrity of the stabilizer.
(g) Flight cycles, as used in this AD, must be counted as defined in Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007 (for Model 707 airplanes); or Boeing 707 Alert Service Bulletin A3516, dated April 4, 2008 (for Model 707 airplanes, and Model 720 and 720B series airplanes).
(h) For airplanes identified in Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007: At the earlier of the times specified in paragraphs (h)(1) and (h)(2) of this AD, determine the type of material of the horizontal stabilizer, rear spar, upper chords, and lower chords on the inboard and outboard ends of the rear spar, in accordance with Part 2 of the Accomplishment Instructions of Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007.
(i) For airplanes with horizontal stabilizer components made from 7075 aluminum, as determined during the inspection required by paragraph (h) of this AD: Within 180 days after the effective date of this AD, and before further flight after any replacement of the horizontal stabilizer, do a special detailed inspection for cracking of the upper chord on the inboard end of the rear spar in the left and right side horizontal stabilizers, from stabilizer station −13.179 to 92.55, in accordance with Part 3 of the Accomplishment Instructions of Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007. Repeat the inspections thereafter at intervals not to exceed 500 flight cycles, and before further flight after any replacement of the horizontal stabilizer, except as provided by paragraph (j) of this AD. If any cracking is found, before further flight, either repair the cracking in accordance with Part 3 of the Accomplishment Instructions of Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007, except as required by paragraph (n) of this AD; or replace the chord with a new chord, in accordance with Part 6 of Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007.
For the purposes of this AD, a special detailed inspection is “an intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. The examination is likely to make extensive use of specialized inspection techniques and/or equipment. Intricate cleaning and substantial access or disassembly procedure may be required.
(j) For airplanes on which the chord is replaced with a new chord in accordance with Part 6 of the Accomplishment Instructions of Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007: Within 4,000 flight cycles after the chord replacement, do the inspections required by paragraph (i) of this AD, and repeat the inspections thereafter at the times specified in paragraph (i) of this AD.
(k) For airplanes with horizontal stabilizers that have components of the chords of the rear spar made from 7079 aluminum, as determined during the inspection required by paragraph (h) of this AD: Within 180 days after the effective date of this AD, do the actions required by paragraphs (k)(1), (k)(2), and (k)(3) of this AD, and repeat those actions at the applicable intervals specified in paragraphs (k)(1), (k)(2), and (k)(3) of this AD.
(1) Do a special detailed inspection for cracking of the upper chord of the inboard side of the rear spar in the left and right side horizontal stabilizers from stabilizer station −13.179 to 92.55, in accordance with Part 3 of the Accomplishment Instructions of Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007. Repeat the inspection thereafter at intervals not to exceed 250 flight cycles or 180 days, whichever occurs first. If any cracking is found during any inspection required by this paragraph, before further flight, either repair the cracking, in accordance with Part 3 of the Accomplishment Instructions of Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007, except as required by paragraph (n) of this AD; or replace the chord with a new chord, in accordance with Part Start Printed Page 728666 of Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007.
(i) Determine whether the cracking meets the limits specified in Part 4 of the Accomplishment Instructions of Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007, and whether a previous repair has been done; determine if all 7079 upper and lower chord segments installed on the horizontal stabilizer have had the Part II, Group 1, Preventative Modification specified in Boeing 707 Service Bulletin 3356 done; and do all applicable repairs and modifications, in accordance with Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007. Do the actions required by this paragraph in accordance with Part 4 of the Accomplishment Instructions of Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007, except as required by paragraph (n) of this AD. Do all applicable repairs and modifications before further flight.
(ii) Replace the chord with a new chord, in accordance with Part 6 of Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007.
(3) Do low frequency eddy current (LFEC) inspections for cracking of the forward skin flanges of the upper and lower chords of the rear spar in the left and right side horizontal stabilizers from stabilizer stations −13.179 to 272.55 (for lower chords) and 92.55 to 272.55 (for upper chords), in accordance with Part 5 of the Accomplishment Instructions of Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007. Repeat the inspections thereafter at intervals not to exceed 1,000 flight cycles or 180 days, whichever occurs first. If any cracking is found during any inspection required by this paragraph, before further flight, do the actions specified in either paragraph (k)(3)(i) or paragraph (k)(3)(ii) of this AD.
(i) Repair cracking, and determine whether all 7079 upper and lower chord segments installed on the horizontal stabilizer have had the Part II—Preventative Modification specified in Boeing 707 Service Bulletin 3381 done, and do all applicable modifications, in accordance with Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007. Do the actions required by this paragraph in accordance with Part 5 of the Accomplishment Instructions of Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007, except as required by paragraph (n) of this AD. Do all applicable modifications before further flight.
(l) For airplanes identified in Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007, with horizontal stabilizers that have rear spar chord components made from 7079 aluminum and have not had embodied the modification of Part II of Boeing 707 Service Bulletin 3381, dated July 25, 1980; or Revision 1, dated July 31, 1981: Before further flight after determining the type of material in accordance with paragraph (h) of this AD, modify all 7079 chord segments still installed on the horizontal stabilizer, in accordance with Part 5 of the Accomplishment Instructions of Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007; or replace the chord, in accordance with Part 6 of the Accomplishment Instructions of Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007.
(m) For all airplanes: Within 180 days or 1,000 flight cycles after the effective date of this AD, whichever occurs first, do the inspections of the applicable structurally significant items specified in and in accordance with the Accomplishment Instructions of Boeing 707 Alert Service Bulletin A3516, dated April 4, 2008. If any cracking is found, before further flight, repair in accordance with the procedures specified in paragraph (q) of this AD. The inspections required by AD 85-12-01 R1, Amendment 39-5439 (51 FR 36002, October 8, 1986), are still required, except, as of the effective date of this AD, the flight-cycle interval for the repetitive inspections specified in paragraph 1.E., “Compliance,” of Boeing 707 Alert Service Bulletin A3516, dated April 4, 2008, must be counted in accordance with the requirements of paragraph (g) of this AD.
(n) If any cracking is found during any inspection required by this AD, and Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007, specifies to contact Boeing for appropriate action: Before further flight, repair the cracking using a method approved in accordance with the procedures specified in paragraph (q) of this AD.
(o) Where Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007, specifies that operators “refer to” NDT procedures, the procedures must be done in accordance with the service information identified in paragraphs (o)(1), (o)(2), and (o)(3) of this AD, as applicable.
(1) Subject 51-00-00, “Structures-General,” Figure 20, “Electrical Conductivity Measurement for Aluminum,” of Part 6-Eddy Current, of the Boeing 707/720 Nondestructive Test Manual, Document D6-48023, Revision 118, dated July 15, 2011.
(2) Subject 55-10-07, “Horizontal Stabilizer,” of Part 6-Eddy Current, of the Boeing 707/720 Nondestructive Test Manual, Document D6-48023, Revision 118, dated July 15, 2011.
(3) Subject 51-01-00, “Orientation and Preparation for Testing” of Part 1-General, of the Boeing 707/720 Nondestructive Test Manual, Document D6-48023, Revision 118, dated July 15, 2011.
(p) As of the effective date of this AD, no person may install any horizontal stabilizer assembly with any chord segment having a part number other than that identified in paragraph 2.C.2. of Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007, on any airplane.
(q)(1) The Manager, Seattle Aircraft Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the ACO, send it to the attention of the person identified in the Related Information section of this AD Information may be emailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.
(r) For more information about this AD, contact Berhane Alazar, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office (ACO), 1601 Lind Avenue SW., Renton, Washington 98057-3356; phone: (425) 917-6577; fax: (425) 917-6590; email: berhane.alazar@faa.gov.
(s) For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P. O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone (206) 544-5000, extension 1; fax (206) 766-5680; email me.boecom@boeing.com; Internet https://www.myboeingfleet.com. You may review copies of the referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington. For information on the availability of this material at the FAA, call (425) 227-1221.
[FR Doc. 2011-30582 Filed 11-25-11; 8:45 am]