Airworthiness Directive · Amendment 39-14942 · Boeing Model 747-400 Series Airplanes
Boeing Model 747-400 Series Airplanes
This AD applies to Boeing Model 747-400 series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 747-25A3353, dated December 9, 2004.
The FAA is superseding an existing airworthiness directive (AD), which applies to certain Boeing Model 747-400 series airplanes. That AD currently requires replacement of the decompression panels that are located in the smoke barrier between the passenger and main deck cargo compartment with new panels of an improved design. This new AD requires modification of the decompression panels on the smoke barrier in the main deck cargo compartment, or replacement of the smoke barrier with an improved smoke barrier, as applicable. This new AD also requires repetitive inspections of the decompression (vent) panels on the smoke barrier and corrective actions if necessary. This new AD also adds airplanes to the applicability. This AD results from reports of decompression panels on the smoke barrier opening in flight and on the ground without a decompression event. We are issuing this AD to prevent inadvertent opening or tearing of decompression panels, which could result in degraded cargo fire detection and suppression capability, smoke penetration into an occupied compartment, and an uncontrolled cargo fire, if a fire occurs in the main deck cargo compartment.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
Within 48 months after the effective date of this AD: Modify the decompression panels on the smoke barrier or replace the smoke barrier with an improved smoke barrier, by accomplishing all of the actions specified in Work Package 1 of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-25A3353, dated December 9, 2004, as applicable.
Within 20 months or 6,000 flight hours after accomplishing the actions in paragraph (f) of this AD, whichever occurs first: Do a general visual inspection of the decompression (vent) panels on the smoke barrier for any changes from their installed condition, and do all corrective actions before further flight after the inspection, by accomplishing all of the actions specified in Work Package 2 of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-25A3353, dated December 9, 2004, as applicable. Repeat the inspection thereafter at intervals not to exceed 20 months or 6,000 flight hours, whichever occurs first.
Note 1: For the purposes of this AD, a general visual inspection is: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to ensure visual access to all surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”
