Airworthiness Directive · Amendment 39-11915 · McDonnell Douglas Model MD-90-30 Series Airplanes
McDonnell Douglas Model MD-90-30 Series Airplanes
Superseded. A later AD replaced this one: AD 2001-20-20. Comply with the one in force.
Model MD-90-30 series airplanes, as listed in McDonnell Douglas Alert Service Bulletin MD90-24A060, Revision 01, dated September 2, 1999, and McDonnell Douglas Service Bulletin MD90-24-062, dated February 3, 2000; 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 document supersedes an existing airworthiness directive (AD) that applies to certain McDonnell Douglas Model MD-90-30 series airplanes. That AD currently requires replacement of certain ground block screws with new screws; and retermination of the circuit ground wires of the electrical power control unit (EPCU) to separate grounding points. The actions specified in that AD are intended to prevent a loose electrical ground block of the circuit ground wires of the EPCU, which could result in complete loss of the primary electrical power of an airplane during flight. This amendment is prompted by the Federal Aviation Administration's determination that the existing AD must be revised to ensure that the requirements apply to the appropriate airplane groups.
To prevent a loose electrical ground block of the circuit ground wires of the electrical power control unit (EPCU), accomplish the following:
(a) For airplanes listed in McDonnell Douglas Alert Service Bulletin MD90-24A060, Revision 01, dated September 2, 1999: Within 30 days after the effective of this AD, replace the electrical ground block screws with new screws in accordance with McDonnell Douglas Alert Service Bulletin MD90-24A060, Revision 01, dated September 2, 1999.
Note 2: Accomplishment of the replacement of electrical ground block screws prior to the effective date of this AD in accordance with McDonnell Douglas Alert Service Bulletin MD90-24A060, dated July 28, 1999, is acceptable for compliance with the requirements of paragraph (a) of this AD.
(b) For airplanes listed in McDonnell Douglas Service Bulletin MD90-24-062, dated February 3, 2000: Within 12 months after the effective date of this AD, reterminate the circuit ground wires of the EPCU to separate grounding points to ensure that a single point failure does not occur, in accordance with McDonnell Douglas Service Bulletin MD90-24-062, dated February 3, 2000.
