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93-01-26: 93-01-26 DE HAVILLAND, INC.: Amendment 39-8480. Docket 92-NM-99-AD. Supersedes AD 91-19-04, Amendment 39-8031 which superseded AD 91-12-51, Amendment 39-7076.
Applicability: Model DHC-8-300 series airplanes; serial numbers 202, 210, 216, 221, 224, 230, 232, 234, 236, 238, 240, 242, 244, 246, 248, 250, 252, 254, 256, 257, 259, 261, 262, 264, 266, 267, 269, 271, 272, 274, 276, 278, 279, 281, 283, 284, 286, 288, and 307; certificated in any category.
Compliance: Required as indicated, unless accomplished previously.
To prevent the accumulation of fuel vapors in the dry bay area, presenting a potential risk of an in-flight explosion in the event of a lightning strike, accomplish the following:
(a) For those airplanes listed in de Havilland Alert Service Bulletin S.B. A8-28-16, dated May 30, 1991, accomplish the following:
(1) Within 24 hours after August 26, 1991 (the effective date of AD 91-12- 51, Amendment 39-7076), and thereafter at intervals not to exceed 300 hours time-in-service or 30 days, whichever occurs first, perform an external visual inspection of the wing dry bay drains for blockage in accordance with the service bulletin. If drain blockage is found, prior to further flight, repair in accordance with paragraph B.1. of the Accomplishment Instructions of the service bulletin.
(2) Within 24 hours after August 26, 1991, and thereafter at daily intervals, perform an external visual inspection of the wing dry bay drains to detect evidence of fuel leaks in accordance with the service bulletin.
(3) Within 7 days after August 26, 1991, unless accomplished within the previous 14 days; or prior to further flight if evidence of fuel leaks is detected at the wing dry bay drains as a result of the inspection required by paragraph (a)(2) of this AD; perform an internal visual inspection of the wing dry bay in accordance with the service bulletin.
(i) If no leakage is found as a result of the inspection required by paragraph (a)(3) of this AD, repeat the internal visual inspection of the wing dry bay required by paragraph (a)(3) of this AD at intervals not to exceed 14 days.
(ii) If the leakage is within the limits specified in the service bulletin, within 14 days, perform the local re-sealing repair procedure described in paragraph C.7. of the Accomplishment Instructions of the service bulletin. The airplane may be returned to service within this 14-day period, subject to the following conditions:
(A) Perform the internal visual inspection of the wing dry bay required by paragraph (a)(3) of this AD at intervals not to exceed 7 days to ensure that the leakage remains within the specified limit; and
(B) Prior to further flight, incorporate the following into the Limitations Section of the Airplane Flight Manual (AFM), which may be accomplished by including a copy of this airworthiness directive in the AFM:
"Flight is prohibited in areas where lightning or thunderstorms are observed or reported within 5 nautical miles of the flight path, or when the existing weather conditions may reasonably be expected to result in a lightning strike."
(iii) If leakage exceeds the limit specified in the service bulletin, prior to further flight, repair in accordance with paragraph C.7. of the Accomplishment Instructions of the service bulletin.
(iv) Application of a fuel vapor barrier coating in accordance with paragraph D. of the Accomplishment Instructions of the service bulletin constitutes terminating action only for the repetitive internal visual inspections required by paragraph (a)(3)(i) of this AD.
(b) For those airplanes listed in de Havilland Alert Service Bulletin S.B. A8-28-16, Revision 'B', dated June 24, 1991, that are not subject to paragraph (a) of this AD, accomplish the following:
(1) Within 24 hours after September 26, 1991 (the effective date of AD 91- 19-04, Amendment 39-8031), and thereafter at intervals not to exceed 300hours time-in-service or 30 days, whichever occurs first, perform an external visual inspection of the wing dry bay drains for blockage in accordance with the service bulletin. If drain blockage is found, prior to further flight, repair in accordance with paragraph B.1. of the Accomplishment Instructions of the service bulletin.
(2) Within 24 hours after September 26, 1991, and thereafter at daily intervals, perform an external visual inspection of the wing dry bay drains to detect evidence of fuel leaks in accordance with the service bulletin.
(3) Within 7 days after September 26, 1991, unless accomplished within the previous 14 days; or prior to further flight if evidence of fuel leaks is detected at the wing dry bay drains as a result of the inspection required by paragraph (b)(2) of this AD; perform an internal visual inspection of the wing dry bay in accordance with the service bulletin.
(i) If no leakage is found as a result of the inspection required by paragraph (b)(3) of this AD, repeat the internal visual inspection of the wing dry bay required by paragraph (b)(3) of this AD at intervals not to exceed 14 days.
(ii) If the leakage is within the limits specified in the service bulletin, within 14 days, perform the local re-sealing repair procedure described in paragraph C.7. of the Accomplishment Instructions of the service bulletin. The airplane may be returned to service within this 14-day period, subject to the following conditions:
(A) Perform the internal visual inspection of the wing dry bay required by paragraph (b)(3) of this AD at intervals not to exceed 7 days to ensure that the leakage remains within the specified limit; and
(B) Prior to further flight, incorporate the following into the Limitations Section of the Airplane Flight Manual (AFM), which may be accomplished by including a copy of this airworthiness directive in the AFM:
"Flight is prohibited in areas where lightning or thunderstorms are observed or reported within 5 nautical miles of the flight path, or when the existing weather conditions may reasonably be expected to result in a lightning strike."
(iii) If leakage exceeds the limit specified in the service bulletin, prior to further flight, repair in accordance with paragraph C.7. of the Accomplishment Instructions of the service bulletin.
(iv) Application of a fuel vapor barrier coating in accordance with paragraph D. of the Accomplishment Instructions of the service bulletin constitutes terminating action only for the repetitive internal visual inspections required by paragraph (b)(3)(i) of this AD.
(c) For airplane serial numbers 279, 281, 283, 284, 286, 288, and 307, accomplish the following in accordance with de Havilland Alert Service Bulletin S.B. A8-28-16, Revision 'C', dated January 31, 1992:
(1) Within 7 days after the effective date of this AD, and thereafter at intervals not to exceed 300 hours time-in-service or 30 days, whichever occurs first, perform an external visual inspection of the wing dry bay drains for blockage in accordance with the service bulletin. If drain blockage is found, prior to further flight, repair in accordance with paragraph B.1. of the Accomplishment Instructions of the service bulletin.
(2) Within 7 days after the effective date of this AD, and thereafter at daily intervals, perform an external visual inspection of the wing dry bay drains to detect evidence of fuel leaks in accordance with the service bulletin.
(3) Within 7 days after the effective date of this AD, unless accomplished within the previous 14 days; or prior to further flight if evidence of fuel leaks is detected at the wing dry bay drains as a result of the inspection required by paragraph (c)(2) of this AD; perform an internal visual inspection of the wing dry bay in accordance with the service bulletin.
(i) If no leakage is found as a result of the inspection required by paragraph (c)(3) of this AD, repeat the internal visual inspection of the wing dry bay required by paragraph (c)(3) of this AD at intervals not to exceed 14 days.
(ii) If the leakage is within the limits specified in the service bulletin, within 14 days, perform the local re-sealing repair procedure described in paragraph C.7. of the Accomplishment Instructions of the service bulletin. The airplane may be returned to service within this 14-day period, subject to the following conditions:
(A) Perform the internal visual inspection of the wing dry bay required by paragraph (c)(3) of this AD at intervals not to exceed 7 days to ensure that the leakage remains within the specified limit; and
(B) Prior to further flight, incorporate the following into the Limitations Section of the Airplane Flight Manual (AFM), which may be accomplished by including a copy of this airworthiness directive in the AFM:
"Flight is prohibited in areas where lightning or thunderstorms are observed or reported within 5 nautical miles of the flight path, or when the existing weather conditions may reasonably be expected to result in a lightning strike."
(iii) If leakage exceeds the limit specified in the service bulletin, prior to further flight, repair in accordance with paragraph C.7. of the Accomplishment Instructions of the service bulletin.
(iv) Application of a fuel vapor barrier coating in accordance with paragraph D. of the Accomplishment Instructions of the service bulletin constitutes terminating action only for the repetitive internal visual inspections required by paragraph (c)(3)(i) of this AD.
(d) Within 6 months after the effective date of this AD, accomplish Modification No. 8/1776 in accordance with de Havilland Service Bulletin S.B. 8-57-20, Revision A, dated January 31, 1992. Accomplishment of this modification constitutes terminating action for the requirements of this AD.
(e) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, New York Aircraft Certification Office (ACO), ANE-170, FAA, Engine and Propeller Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, New York ACO.
NOTE: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the New York ACO.
(f) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the airplane to a location where the requirements of this AD can be accomplished.
(g) Certain inspections, repairs, and modification shall be done in accordance with de Havilland Alert Service Bulletin S.B. A8-28-16, dated May 30, 1991; de Havilland Alert Service Bulletin S.B. A8-28-16, Revision 'C', dated January 31, 1992; and de Havilland Service Bulletin S.B. 8-57-20, Revision 'A', dated January 31, 1992; as indicated. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Certain other inspections, repairs, and modifications shall be done in accordance with de Havilland Alert Service Bulletin S.B. A8-28-16, Revision 'B', dated June 24, 1991. Incorporation by reference of de Havilland Alert Service Bulletin S.B. A8-28-16, Revision 'B', dated June 24, 1991, was approved previously by the Director of the Federal Register as of September 26, 1991 (56 FR 46228, September 11, 1991). Copies may be obtained from de Havilland, Inc., Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, New York Aircraft Certification Office, 181 South Franklin Avenue, Valley Stream, New York; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington,DC.
(h) This amendment becomes effective on March 10, 1993.
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