90-21-18: Rubber Radome Seal

90-21-18 GULFSTREAM: Amendment 39-6762. Docket No. 90-NM-87-AD. Applicability: Model G-IV series airplanes, Serial Numbers 1000 through 1130, certificated in any category. Compliance: Required as indicated, unless previously accomplished. To prevent in-flight failure of avionics equipment due to water intrusion, accomplish the following: A. Within 25 hours time-in-service or within 30 days after the effective date of this AD, whichever occurs later, install additional sealant on the upper portion of the radome and fuselage mating structure, and inspect the integrity of the rubber radome seal and aerodynamic seal, in accordance with Gulfstream Aerospace Aircraft Service Change (ASC) 183, dated March 15, 1990. 1. If defects are found in the rubber radome seal, replace prior to further flight, in accordance with ASC 183. 2. If defects are found in the aerodynamic seal, repair prior to further flight, in accordance with ASC 183. B. An alternate means of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Atlanta Aircraft Certification Office (ACO), ACE-115A, FAA, Central Region. NOTE: The request should be submitted directly to the Manager, Atlanta ACO, and a copy sent to the cognizant FAA Principal Inspector (PI). The PI will then forward comments or concurrence to the Manager, Atlanta ACO. C. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD. All persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to Gulfstream Aerospace Corporation, P.O. Box 2206, M/S D-10, Savannah, Georgia 31402-9980. These documents may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue S.W., Renton,Washington, or at the FAA, Central Region, Atlanta Aircraft Certification Office, 1669 Phoenix Parkway, Suite 210C, Atlanta, Georgia. This amendment (39-6762, AD 90-21-18) becomes effective on November 14, 1990.