EASA AD US-2021-14-10
Equipment / Furnishings - Forward Cargo Compartment Insulation Blankets - Inspection
Summary
The Federal Aviation Administration (FAA) Airworthiness Directive 2021-14-10 is a final rule addressing certain Boeing 747-400, 747-400D, and 747-400F series airplanes. It mandates inspections of the forward cargo compartment insulation blankets for degraded Boeing Material Specification (BMS) 8-39 urethane foam, which has diminished fire-retardant properties with age. The directive requires replacement of exposed or compromised foam and seals to maintain fire safety standards.
What Changed
This new airworthiness directive introduces mandatory inspections of insulation blankets in the forward cargo compartment between station 960 and 1000 on both sides of the airplane. It requires checking for exposed BMS 8-39 urethane foam not protected by fire-resistant barriers and verifying seal integrity, with replacement mandated if deficiencies are found. The directive also clarifies compliance timelines and provides procedures via Boeing Special Attention Requirements Bulletin 747-25-3725 RB dated October 27, 2020.
Why It Matters
This directive is critical for aviation professionals because degraded BMS 8-39 urethane foam can fail to maintain adequate halon concentrations needed to extinguish or contain fires or smoke in cargo compartments. Failure to address this unsafe condition could lead to undetected fire or smoke penetration in hard-to-access areas, potentially resulting in loss of airplane control. Operators and maintenance teams must ensure compliance to uphold safety and regulatory standards.
What To Do
Operators of affected Boeing 747-400 series airplanes must perform a general visual inspection of the forward cargo compartment insulation blankets within the compliance times specified in the Boeing Special Attention Requirements Bulletin 747-25-3725 RB. Any exposed BMS 8-39 urethane foam or compromised seals must be replaced promptly. The directive is effective August 19, 2021, and compliance must be achieved according to the specified schedule in the service bulletin.
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