76-13-08 FAIRCHILD: Amendment 39-2658. Applies to F-27 and FH-227 Type Airplanes, certificated in all categories.
Compliance required as indicated for all airplanes with 7500 hours in service on the upper engine mount attachment bolts AN4, AN5, AN6 and their nuts:
(a) For F-27J, F-27M and FH-227 Type Airplanes, perform the inspections (1) through (4) specified in (c) below within the next 25 hours in service or four days, whichever occurs first, unless accomplished within the last 125 hours in service and at intervals thereafter not to exceed 150 hours in service from the last inspection.
(b) For F-27, F-27A, F-27B and F-27F Type Airplanes, perform the inspections (1) through (4) specified in (c) below within the next 300 hours in service or 90 days, whichever occurs first, unless accomplished within the last 300 hours in service or 90 days and at intervals thereafter not to exceed 600 hours in service or 180 days, whichever occurs first, from the last inspection.(c) Inspect all engine mount attachment bolts on all upper inboard and outboard engine mount fittings, P/N 27-110105 or P/N 01-1101-5 as follows:
(1) Visually check all bolts for gaps under bolt heads and looseness.
(2) Torque bolts to check for tightness without exceeding standard torque values for bolt heads.
(3) Check for gap between fitting and spar web using a .0015 feeler gage, by placing feeler gage between AN6 and AN4 bolt locations on both sides of the fitting.
(4) Where gaps in excess of .0014, looseness, broken bolts, or any bolt rotation is found, AN4, AN5, or AN6 bolts and their respective AN or NAS Nuts, must be replaced before further flight with unused AN Bolts and AN or NAS Nuts with the same part number or with the respective NAS 1304, NAS 1305 or NAS 1306 bolts, using MS21042 nuts or with equivalent parts approved by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region.
(d) For F-27J, F-27M and FH-227 Type Airplanes, within the next 900 hours in service or one year, whichever comes first, after the effective date of this AD, unless already accomplished, replace all AN Bolts with those bolts and nuts specified in (c)(4).
(e) For F-27, F-27A, F-27B and F-27F Type Airplanes, within the next 1800 hours in service or two years, whichever comes first, after the effective date of this AD, unless already accomplished, replace all AN Bolts with those bolts and nuts specified in (c)(4).
(f) If unused AN Bolts and AN or NAS Nuts are used for replacement, upon the accumulation of 7500 hours in service, the inspections specified in (a) or (b) and (c), and replacement in accordance with (d) or (e) must be accomplished.
(g) The repetitive inspection required by (a) or (b) and (c) may be discontinued when all AN4, AN5 and AN6 Bolts are replaced by the NAS Bolts and MS Nuts specified in (c)(4).
(h) The repetitive inspection compliance time may be increased by the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region, upon receipt of substantiating data submitted through an FAA Maintenance Inspector.
(i) Report the results of the initial inspection findings, required by this AD, to the Chief, Engineering and Manufacturing Branch, FAA, Eastern Region (Reporting Approved by the Office of Management and Budget under OMB No. CA-R0174).
(Fairchild Service Bulletins F27-54-22 and FH227-54-16 pertain to this subject.)
This amendment is effective July 7, 1976.