Airworthiness Directive · Amendment 39-17176 · Stabilizers
The Boeing Company Airplanes
Superseded. A later AD replaced this one: AD 2016-08-11. Comply with the one in force.
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.
We are adopting 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. 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 potential early fatigue cracking in the chord segments made from 7075 aluminum. For certain airplanes, this AD requires using redefined flight cycle counts, determining the type of material of the horizontal stabilizer, rear spar, and upper 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 modifying chord segments made from 7079 aluminum, if necessary. For all airplanes, this AD requires inspecting certain structurally significant items, and repairing discrepancies if necessary. We are issuing this AD to detect and correct stress corrosion and/or potential early fatigue cracking in the horizontal stabilizer, which could compromise the structural integrity of the stabilizer.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
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 airplanes); or Boeing 707 Alert Service Bulletin A3516, dated April 4, 2008 (for Model airplanes, and Model 720 and 720B series airplanes).
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.
(1) Within 180 days after the effective date of this AD.
(2) Before further flight after any horizontal stabilizer is replaced after the effective date of this AD.
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 on both 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 the Accomplishment Instructions of Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007.
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.
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 of both 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 6 of the Accomplishment Instructions of Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007.
(2) Do a high frequency eddy current inspection for cracking of the web flanges of the upper and lower chords of the rear spar in the left and right side horizontal stabilizers from stabilizer stations 92.55 to 272.55, in accordance with Part 4 of the Accomplishment Instructions of Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007. Repeat the inspection 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 paragraph (k)(2)(i) or (k)(2)(ii) of this AD.
(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 the Accomplishment Instructions of 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 the Accomplishment Instructions 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 any cracking, 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 the Accomplishment Instructions of 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.
(ii) Replace the chord with a new chord, in accordance with Part 6 of the Accomplishment Instructions of Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007.
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 Boeing 707 Service Bulletin 3381, 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 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.
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.
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.
Where Boeing 707 Alert Service Bulletin A3515, dated December 19, 2007, specifies that operators “refer to” nondestructive test (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) Figure 20, “Electrical Conductivity Measurement for Aluminum,” of Subject 51-00-00, “Structures-General,” 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.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Aircraft
