83-07-05 R3 AEROSPATIALE HELICOPTER CORPORATION (SNIAS): Amendment 39-4599 as amended by Amendment 39-4698 and Amendment 39-4887 is further amended by Amendment 39-5128. Applies to Aerospatiale Model AS-350 and AS-355 series helicopters certificated in all categories.
Compliance is required as indicated (unless already accomplished).
To prevent possible failure of the main rotor mast, accomplish the following:
a. For helicopters which have 250 hours or more total time in service on the main rotor mast on the effective date of this AD, inspect in accordance with paragraph d. within 50 hours time in service, unless already accomplished.
b. For those helicopters which have less than 250 hours total time in service on the main rotor mast on the effective date of this AD, inspect in accordance with paragraph d. before reaching 300 hours time in service on the main rotor mast, unless already accomplished.
c. For those helicopters exhibiting a severe tracking defect, inspect in accordance with paragraph d. before further flight, unless already accomplished.
d. Remove the main rotor hub from the main rotor mast in accordance with the Model AS-350 or AS-355 Maintenance Manual, or FAA approved equivalent as appropriate.
(1) Visually inspect the upper main rotor mast areas above the swashplate for surface finish deterioration, corrosion, or cracks. Conduct the visual inspection on all accessible mast areas with special emphasis in the areas of the 12 flange bolt holes and in the radius between the mast flange and the mast cylindrical shaft. Use a 10-power glass in areas of suspected surface finish cracks.
(2) Conduct a magnetic particle or dye penetrant inspection of the flange radius of the mast area described in subparagraph (d)(1) from which the surface finish has deteriorated to the extent that unprotected metal is exposed (even by cracks in the finish).
e. For AS-355 helicopters (within 10 hours time in service from theeffective date of this amended AD, unless already accomplished):
(1) Repeat the inspections of paragraph d of this AD at intervals not to exceed 300 hours time in service from the last paragraph d inspection.
(2) Visually inspect the mast upper flange-to-shaft radius before the first flight of each day. Inspect for finish deterioration, corrosion, or cracks. Use a 10-power glass in areas of suspected surface finish cracks. Conduct magnetic particle or dye penetrant inspections, in accordance with paragraph d(3) of this AD, of all areas where finish deterioration is found.
(3) Upon accumulation of 450 hours total time in service, remove from service any main rotor mast which does not qualify for limited saline environment operation. To qualify for consideration of limited saline environment operations, an individual Model AS-355 helicopter mast must comply with all the following:
(i) It must not be operated over saltwater for a major part (excess of 50 percent) of any month.
(ii) It must not have a total of 300 hours or more time in service of over saltwater operations.
(iii) It must not be installed on a helicopter that had a main rotor mast replaced due to corrosion.
f. For AS-350 helicopters (within 10 hours time in service from the effective date of this amended AD, unless already accomplished):
(1) Repeat the inspections of paragraph d of this AD at intervals not to exceed 300 hours time in service from the last paragraph d inspection.
(2) Visually inspect the mast upper flange-to-shaft radius before the first flight of each day. Inspect for finish deterioration, corrosion, or cracks. Use a 10-power glass in areas of suspected surface finish cracks. Conduct magnetic particle or dye penetrant inspections in accordance with paragraph d(2) of this AD of all areas where finish deterioration is found.
g. Rework corroded masts in accordance with Aerospatiale Service Bulletin Nos. 05.08 or 05.13, datedApril 19, 1983, or later FAA-approved equivalent. Replace any masts corroded beyond the allowed rework.
h. Reinstall the main rotor hub in accordance with the appropriate Model AS-350 or AS-355 Maintenance Manual, or FAA-approved equivalent, after completion of the inspections and rework of paragraphs d, e, f, and g.
i. Any equivalent method of compliance with this AD must be approved by the Manager, Aircraft Certification Division, Federal Aviation Administration, 4400 Blue Mound Road, Fort Worth, Texas 76101 or by the Manager, Aircraft Certification Staff, AEU-100, Europe, Africa, and Middle East Office, Federal Aviation Administration, c/o American Embassy, Brussels, Belgium.
j. In accordance with FAR 21.197, flight is permitted to a base where the inspections required by this AD may be accomplished.
k. After the installation of corrosion resistant masts (P/N 350A.37.1076.07), the repetitive inspections and life limits of paragraphs d, e, and f, no longer apply.Amendment 39-4599 became effective April 8, 1983.
Amendment 39-4698 became effective August 26, 1983.
Amendment 39-4887 became effective August 17, 1984.
This amendment 39-5128 becomes effective September 18, 1985.