Airworthiness Directive · Amendment 39-11810 · Boeing Model 747 Series Airplanes
Boeing Model 747 Series Airplanes
Model 747 series airplanes; as listed in Boeing Special Attention Service Bulletin 747-32-2461, dated August 19, 1999; certificated in any category.
Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (c) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747 series airplanes, that requires replacement of any brake system accumulator that has aluminum end caps with an accumulator that has stainless steel end caps. This amendment is prompted by reports of fractures of aluminum end caps on brake system accumulators. The actions specified by this AD are intended to prevent high-velocity separation of a brake system accumulator barrel, piston, or end cap, which could result in injury to personnel in the wheel well area, loss of cabin pressurization, loss of certain hydraulic systems, or damage to the fuel line of the auxiliary power unit.
To prevent high velocity separation of a brake system accumulator barrel, piston, or end cap; which could result in injury to personnel in the wheel well area, loss of cabin pressurization, loss of certain hydraulic systems, or damage to the fuel line of the auxiliary power unit; accomplish the following:
(a) At the next “C”-check, not to exceed 6,000 flight hours after the effective date of this AD, replace any brake system accumulator that has aluminum end caps with an accumulator that has stainless steel end caps in accordance with Boeing Special Attention Service Bulletin 747-32-2461, dated August 19, 1999.
(b) As of the effective date of this AD, no person shall install a brake system accumulator having part number (P/N) BACA11E1 (Parker P/N 2660472-1 or 2660472M1) or BACA11E5 (Parker P/N 2660472-5 or 2660472M5) on any airplane.
