Airworthiness Directive · Amendment 39-14100 · Boeing Model 747-200C and 747-200F Series Airplanes
Boeing Model 747-200C and 747-200F Series Airplanes
This AD applies to all Boeing Model 747-200C and 747-200F series airplanes, certificated in any category.
The FAA is adopting a new airworthiness directive (AD) for all Boeing Model 747-200C and 747-200F series airplanes. This AD requires repetitive inspections for cracking of the left and right C-3 frame upper closure fittings of the nose cargo door, and corrective actions if necessary. This AD also provides an optional modification that, if done, terminates inspections in certain areas. This AD is prompted by reports indicating that fatigue cracking was found in the inboard flange above the flight deck floor on the C-3 frame upper closure fittings of the nose cargo door. We are issuing this AD to detect and correct cracking of the C-3 frame upper closure fittings, which could extend and result in rapid depressurization 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.
Do a detailed inspection of the left and right C-3 frame upper closure fittings of the nose cargo door, including the flight deck floor tang, according to the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2495, dated December 18, 2003. Do the initial inspection at the applicable compliance time specified in Figure 1 (Group 1 and 2 airplanes) or 2 (Group 3 and 4 airplanes) of the service bulletin, as applicable; except, where the service bulletin specifies a compliance time relative to the date of the initial release of the service bulletin, this AD requires compliance relative to the effective date of this AD. Repeat the inspection thereafter at intervals not to exceed 3,000 flight cycles, except as provided by paragraph (h) of this AD.
Note 1: For the purposes of this AD, a detailed inspection is: “An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.”
If any cracking is found during any inspection required by this AD: Before further flight, do applicable repairs or replace the fitting with a new fitting, according to the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2495, dated December 18, 2003; except, where the bulletin specifies to contact Boeing for appropriate action, before further flight, repair in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or in accordance with data meeting the certification basis of the airplane approved by an Authorized Representative for the Boeing Delegation Option Authorization Organization who the Manager, Seattle ACO, has authorized to make this finding. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD.
Doing all actions associated with the modification of the upper closure fitting, including performing an open-hole high frequency eddy current inspection for cracking of certain fastener holes and all applicable corrective actions; according to Figure 4 of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2495, dated December 18, 2003; terminates the repetitive inspections of the upper part of the upper closure fitting required by paragraph (f) of this AD. However, inspections of the flight deck floor tang must continue, as required by paragraph (f) of this AD.
Note 2: There is no terminating action available at this time for the inspections of the flight deck floor tang required by paragraph (f) of this AD.
(i) While Note 4 of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2495, dated December 18, 2003, provides for adjusting the flight cycle threshold specified in the service bulletin by not counting flight cycles with a cabin pressure differential of 2.0 pounds per square inch or less, this AD does not allow this adjustment.
