Airworthiness Directive · Amendment 39-11674 · McDonnell Douglas Model MD-11 Series Airplanes
McDonnell Douglas Model MD-11 Series Airplanes
Model MD-11 series airplanes, as listed in McDonnell Douglas Alert Service Bulletin MD11-24A040, Revision 01, dated October 11, 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 (b) 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 McDonnell Douglas Model MD-11 series airplanes, that requires electrical resistance measurements of the ground studs of the No. 2 generator in the electrical power center of the center accessory compartment for proper electrical bonding and of the ground studs and circuit breaker terminations in the forward cargo compartment to detect looseness and for proper electrical bonding; and corrective actions, if necessary. This amendment is prompted by an incident of charred insulation blankets in the forward cargo compartment in the area of the external ground power receptacle and the galley external power circuit breakers, and another incident of a No. 2 "generator off" alert while the generator was still on line. The actions specified by this AD are intended to prevent arcing and overheating of terminals and consequent smoke and fire in the forward cargo compartment due to improper bonding of ground studs in the forward cargo compartment and in the electrical power center and due to improper installation of circuit breaker terminations.
To prevent arcing and overheating of terminals and consequent smoke and fire in the forward cargo compartment due to improper bonding of ground studs in the forward cargo compartment and in the electrical power center (EPC) and due to improper installation of circuit breaker terminations, accomplish the following:
(a) Within 12 months after the effective date of this AD, accomplish the actions specified in paragraphs (a)(1) and (a)(2) of this AD, in accordance with McDonnell Douglas Alert Service Bulletin MD11-24A040, Revision 01, dated October 11, 1999.
(1) Perform an electrical resistance measurement of the ground studs of the No. 2 generator in the electrical power center of the center accessory compartment for proper electrical bonding, in accordance with the service bulletin.
(i) If all ground studs are electrically bonded properly, prior to further flight, tighten applicable fasteners, if necessary, in accordance with the service bulletin.
(ii) If any ground stud is not electrically bonded properly, prior to further flight, electrically bond the ground stud in accordance with the service bulletin.
(2) Perform an electrical resistance measurement of the ground studs and circuit breaker terminations in the forward cargo compartment to detect looseness and for proper electrical bonding, in accordance with the service bulletin.
(i) If all ground studs are electrically bonded properly, prior to further flight, tighten applicable attaching parts in accordance with the service bulletin.
(ii) If any circuit breaker termination is found loose, tighten in accordance with the service bulletin.
(iii) If any ground stud is not electrically bonded properly, prior to further flight, electrically bond the ground stud in accordance with the service bulletin.
