Airworthiness Directive · Amendment 39-16006 · Wings
Boeing Model 707 Airplanes, and Model 720 and 720B Series Airplanes
This AD applies to Boeing 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 A3524, Revision 1, dated September 18, 2008.
The FAA is superseding an existing airworthiness directive (AD), which applies to certain Boeing Model 707 airplanes, and Model 720 and 720B series airplanes. The existing AD currently requires repetitive detailed inspections to detect cracks and corrosion on any existing repairs and at certain body stations (STA) of the visible surfaces of the wing to body terminal fittings including the web, flanges, and ribs; and applicable related investigative and corrective actions. This new AD retains the requirements of the existing AD and requires repetitive ultrasonic inspections to detect any stress corrosion cracks within the outboard flange of the left and right body terminal fittings at STA 820, and related investigative and corrective actions if necessary. This AD also provides an optional terminating action for the repetitive inspections. This AD also adds two airplanes to the applicability. This AD results from reports of cracks found in the wing to body terminal fittings during routine inspections. We are issuing this AD to detect and correct cracks and corrosion in the body terminal fittings above and below the floor, which could cause loss of support for the wing and could adversely affect the structural integrity of the airplane.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
For airplanes identified in Boeing 707 Special Attention Service Bulletin 3524, dated July 18, 2007: Within 24 months after October 2, 2008 (the effective date of AD 2008-17-10), do detailed inspections and applicable related investigative and corrective actions, by accomplishing all the actions specified in the Accomplishment Instructions of Boeing 707 Special Attention Service Bulletin 3524, dated July 18, 2007; or Boeing 707 Alert Service Bulletin A3524, Revision 1, dated September 18, 2008; except as provided by paragraph (h) of this AD. After the effective date of this AD, use only Boeing 707 Alert Service Bulletin A3524, Revision 1, dated September 18, 2008. Repeat the detailed inspections thereafter at intervals not to exceed 24 months. Do all applicable related investigative and corrective actions before further flight.
(h) If any crack or corrosion is found during any inspection required by paragraph (g) of this AD, and Boeing 707 Special Attention Service Bulletin 3524, dated July 18, 2007, or Boeing 707 Alert Service Bulletin A3524, Revision 1, dated September 18, 2008, specifies to contact Boeing for appropriate action: Before further flight, repair the terminal fittings using a method approved in accordance with the procedures specified in paragraph (o) of this AD.
(i) Although Boeing 707 Special Attention Service Bulletin 3524, dated July 18, 2007; and Boeing 707 Alert Service Bulletin A3524, Revision 1, dated September 18, 2008; specify to submit information to the manufacturer, this AD does not include that requirement.
For Group 1 and Group 2 airplanes identified in Boeing 707 Alert Service Bulletin A3524, Revision 1, dated September 18, 2008, on which a modification or repair was done in accordance with Boeing 707/720 Service Bulletin 2912, Revision 1, dated March 13, 1970: At the later of the times specified in paragraphs (j)(1) and (j)(2) of this AD, do an ultrasonic inspection to detect any stress corrosion cracks within the outboard flange of the left and right body terminal fittings at body station (STA) 820, and all applicable related investigative and corrective actions, by accomplishing all the actions specified in the Accomplishment Instructions of Boeing 707 Alert Service Bulletin A3524, Revision 1, dated September 18, 2008, except as provided by paragraph (m) of this AD. Repeat the ultrasonic inspection thereafter at intervals not to exceed 24 months or 2,000 flight cycles, whichever occurs first. Do all applicable related investigative and corrective actions before further flight.
(1) Within 24 months or 2,000 flight cycles after the effective date of this AD, whichever occurs first.
(2) Within 24 months or 2,000 flight cycles after doing the repair or modification, whichever occurs first.
(k) For Group 3 and Group 4 airplanes identified in Boeing 707 Alert Service Bulletin A3524, Revision 1, dated September 18, 2008: Within 2,000 flight cycles or 24 months after the effective date of this AD, whichever occurs first, do an ultrasonic inspection to detect any stress corrosion cracks within the outboard flange of the left and right body terminal fittings at STA 820, and all applicable corrective actions, by accomplishing all the actions specified in the Accomplishment Instructions of Boeing 707 Alert Service Bulletin A3524, Revision 1, dated September 18, 2008, except as provided by paragraph (m) of this AD. Repeat the ultrasonic inspection thereafter at intervals not to exceed 24 months or 2,000 flight cycles, whichever occurs first. Do all applicable corrective actions before further flight.
(l) For Group 4 airplanes identified in Boeing 707 Alert Service Bulletin A3524, Revision 1, dated September 18, 2008: Within 24 months after the effective date of this AD, do detailed inspections for corrosion and cracking of the body terminal fittings at STA 820, and all applicable related investigative and corrective actions, by accomplishing all the actions specified in the Accomplishment Instructions of Boeing 707 Alert Service Bulletin A3524, Revision 1, dated September 18, 2008, except as provided by paragraph (m) of this AD. Repeat the detailed inspections thereafter at intervals not to exceed 24 months. Do all applicable related investigative and corrective actions before further flight.
If any crack or corrosion is found during any inspection required by paragraph (j), (k), or (l) of this AD, and Boeing 707 Alert Service Bulletin A3524, Revision 1, dated September 18, 2008, specifies to contact Boeing for appropriate action: Before further flight, repair the terminal fittings using a method approved in accordance with the procedures specified in paragraph (o) of this AD.
Note 1: Boeing 707 Alert Service Bulletin A3524, Revision 1, dated September 18, 2008, refers to Boeing 707/720 Service Bulletin 2912, Revision 1, dated March 13, 1970, as an additional source of guidance for doing certain inspections and repairs.
Replacing a body terminal fitting with a fitting made from 7075-T73 material, using a method approved in accordance with the procedures specified in paragraph (o) of this AD, terminates the repetitive inspections required by this AD for that fitting only.
