Airworthiness Directive · Amendment 39-15731 · Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, and 747SR Series Airplanes
Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, and 747SR Series Airplanes
This AD applies to Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, and 747SR series airplanes, certificated in any category; as identified in Boeing Service Bulletins 747-27A2398, Revision 1, dated July 31, 2008; and 747-27A2421, Revision 1, dated July 10, 2008.
We are adopting a new airworthiness directive (AD) for certain Boeing Model 747 airplanes identified above. This AD requires modifying the outboard flap track and transmission attachments. This AD results from a joint Boeing and FAA multi-model study (following in-service trailing edge flap structure and drive system events) on the hazards posed by skewing and failed flaps. This study identified the safety concerns regarding the transmission attachment design and the potential loss of an outboard trailing edge flap. We are issuing this AD to prevent certain discrepancies associated with this design (for example, a flap skew or lateral control asymmetry that can cause collateral damage to adjacent hydraulic tubing and subsequent loss of a hydraulic system), which could result in the asymmetric flight control limits being exceeded, and could adversely affect the airplane's continued safe flight and landing.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
Do the following, as applicable: At the time specified in paragraph 1.E. of Boeing Service Bulletins 747-27A2398, Revision 1, dated July 31, 2008; and 747-27A2421, Revision 1, dated July 10, 2008; except as provided by paragraph (g) of this AD, modify the outboard flap track and transmission attachments by doing all actions specified in the Accomplishment Instructions of the service bulletin.
(g) Where Boeing Service Bulletins 747-27A2398, Revision 1, dated July 31, 2008; and 747-27A2421, Revision 1, dated July 10, 2008; specify compliance times relative to the date on the service bulletin, this AD requires compliance within the specified compliance time after the effective date of this AD.
Actions done before the effective date of this AD in accordance with Boeing Alert Service Bulletins 747-27A2421 and 747-27A2398, both dated April 19, 2007, are acceptable for compliance with the requirements of paragraph (f) of this AD.
(i) Accomplishment of the modification specified in paragraph (f) of this AD terminates the requirements of paragraphs (a) and (b) of AD 2001-03-10, amendment 39-12114.
After completing the modifications required by paragraph (f) of this AD, no person may install a part identified in Table 1 of this AD on the modified airplane.
| Part | Part No. |
|---|---|
| Hinge brace assembly for Tracks 1 and 8 | 65B15515-1 |
| 65B15515-2 | |
| 65B15515-9 | |
| 65B15515-10 | |
| Hinge brace assembly for Tracks 2 and 7 | 65B15525-1 |
| 65B15525-2 | |
| 65B15525-7 | |
| 65B15525-8 | |
| 65B17092-1 | |
| 65B17092-2 | |
| Support housing assembly for Tracks 1 and 8 | 65B81982-() |
| Support housing assembly for Tracks 2 and 7 | 65B81950-() |
