Airworthiness Directives

As of March 28, 2025, several Airworthiness Directives (ADs) issued by the FAA, EASA, and other aviation authorities, along with Boeing Service Bulletins (SBs), are applicable to the Boeing 747-400 series. These directives and bulletins address various safety and maintenance concerns to ensure the continued airworthiness of the aircraft. Below is a summary of some key ADs and SBs:

1. Fuel System Safety Enhancements

  • FAA AD 2023-06-04 (Effective March 27, 2023): This directive mandates revisions to the maintenance or inspection programs to incorporate new or more restrictive airworthiness limitations aimed at reducing ignition sources inside fuel tanks, thereby mitigating the risk of fuel tank explosions.
  • FAA Proposed AD (April 11, 2024): Targets certain Boeing 747-400F series airplanes, requiring the application of cap seals to specific fastener collars inside fuel tanks to prevent potential fuel leaks and associated hazards.

2. Structural Integrity

  • FAA AD 2024-14-60 (Effective November 15, 2024): Addresses reports of structural cracks in the fuselage skin lap splice. Operators are required to conduct detailed inspections and implement corrective actions to prevent potential in-flight rapid decompression or loss of structural integrity.
  • Boeing Alert Service Bulletin 747-53A2912 (Dated April 5, 2024): Provides guidance for inspecting and addressing potential fuselage cracks. Compliance with this SB is recommended to maintain structural integrity.

3. Flight Control Systems

  • FAA AD 2006-18-17 (Effective October 13, 2006): Supersedes previous directives concerning the yaw damper actuator portion of the upper and lower rudder power control modules. It requires inspections and potential replacements to prevent rudder malfunctions.
  • Boeing Alert Service Bulletin 747-27A2397 (Dated July 24, 2003): Recommends ultrasonic inspections of the lower and upper rudder power control modules to detect potential issues that could affect flight control.

4. Fuel Quantity Indicating System (FQIS)

  • Boeing Service Bulletin 747-28A2283: Applicable to 747-400F airplanes, Boeing Converted Freighters (BCF), and Large Cargo Freighters (LCF). It outlines procedures for conducting FQIS ground tests and corrective actions to ensure accurate fuel quantity readings.

5. Flight Deck Door Modifications

  • FAA AD 2006-07-06 (Effective April 12, 2006): Requires modifications to the flight deck door to enhance security and safety. This includes installing ballistic- and intrusion-resistant doors as per specified Boeing Service Bulletins.

6. Forward Cargo Door

  • FAA AD 2008-04-21 (Effective March 20, 2008): This directive was issued following reports of broken fasteners in the hinge segments of forward and aft cargo doors on certain Boeing 747 models. It mandates repetitive detailed inspections to detect broken or missing fasteners in the single-row hinge fasteners of the cargo door hinge segments. If any broken fastener is found, the AD requires replacing all fasteners in that hinge segment to prevent potential door opening during flight, which could lead to rapid decompression.

7. Aft Pressure Bulkhead

  • FAA AD 2009-05-06 (Effective April 13, 2009): This directive supersedes a previous AD and addresses the detection and correction of fatigue cracks in areas known as “oil cans” on the web of the aft pressure bulkhead. An oil can is a region on the pressure dome web that moves when pushed from the forward side. The AD requires repetitive detailed inspections of the aft pressure bulkhead for indications of oil cans and previous repairs, with corrective actions as necessary. Undetected cracks in these areas could lead to rapid decompression and over-pressurization of the tail section, potentially resulting in loss of control of the airplane.

Operators should ensure compliance with these directives by incorporating the specified inspections and corrective actions into their maintenance programs to maintain the structural integrity and safety of the Boeing 747-400 aircraft

Compliance Recommendations

  • Regular Review: Operators should regularly review the FAA’s Airworthiness Directives database, EASA’s Safety Publications Tool, and relevant Boeing Service Bulletins to stay updated on current and upcoming directives.
  • Service Bulletin Center: Utilize Boeing’s Service Bulletin Center, a free application that provides relevant FAA Aircraft Service Bulletins tailored to specific Boeing fleets.
  • Maintenance Program Integration: Incorporate all applicable ADs and SBs into the aircraft’s maintenance program to ensure compliance and maintain airworthiness.