61-15-02 FAIRCHILD: Amdt. 308 Part 507 Federal Register July 13, 1961. Applies to Type F-27 aircraft, all serial numbers (including FH-227 serial numbers).
Compliance required as indicated.
Because of cases of failure of the gimbal nuts in the wing flap actuating screwjacks which render the gimbal nuts unsafe for further use, the following shall be accomplished:
(a) Until such time as the wing flap gimbal support installation is modified and new gimbal nuts are installed in accordance with Fairchild Service Bulletin No. 27-28 or equivalent, the following inspections shall be made within 100 hours' time in service since last inspected per Amendment 66, AD 59-26-4 and every 100 hours' time in service thereafter.
(1) Check flaps for proper rigging in accordance with F-27 Maintenance Manual, Chapter 27, Subject 5, making sure that no preload exists between the inboard and outboard screwjack of each inboard and outboard flap. Lower flaps to approximately 16 1/2 degreesposition. Move flap up and down at the trailing edge and measure or sense with fingers for radial or linear play between screwjack and gimbal nut. If relative movement between the screwjack and gimbal nut exceeds 0.010 inch radially or linearly, the gimbal nut must be removed from the screwjack and the threads visually inspected for damage. Any indication of thread extrusion or roll calls for immediate replacement. If relative motion between the screwjack and the gimbal nut exceeds 0.030 inch linear or 0.045 inch radial, the gimbal nut must be replaced.
(2) Conduct visual inspection for freedom of movement and lubricate all inboard and outboard wing flap gimbal nuts P/N's 27-165012-3, -4, -5, -6; P/N's 27-175023-3, -4; bushings P/N 27-165013-3, and spindles P/N's 27175017-21, 27-175022-3, 27-165011-21, 27- 165023-21.
(b) When the wing flap gimbal support installation is modified and new gimbal nuts are installed in accordance with Fairchild Service Bulletin 27-28 or equivalent, the inspections specified in paragraphs (c) and (d) shall be accomplished.
(c) Either the (c) (1) or (c) (2) inspection and lubrication procedures must be accomplished. The specified time period for compliance shall commence either at the time the modifications specified in paragraph (b) are incorporated or at the time of the last inspection per paragraph (a).
(1) Every 125 hours' time in service, conduct an inspection per (c)(3) and lubricate all inboard and outboard wing flap gimbal nuts and screwjacks with grease, ANDEROL L-736 or equivalent, and lubricate universal joints and spindle gimbal nut bushings with oil, Spec. MIL-L-15016.
(2) Every 150 hours' time in service, conduct an inspection per (c)(3). Every 75 hours' time in service, lubricate all inboard and outboard wing flap gimbal nut and screwjacks with grease, ANDEROL L-736 or equivalent, and lubricate universal joints and spindle gimbal nut bushings with oil, Spec. MIL-L-15016.
(3) Lower flaps to 16.5degrees position and move flaps up and down at the trailing edge and check for axial and radial play between the screwjacks and gimbal nuts. If the relative motion between the screwjacks and gimbal nut exceeds the values listed below, the gimbal nut must be replaced prior to further flight except ferry flight in accordance with the provisions of CAR 1.76. Also, visually check the gimbal nuts in place on the aircraft for indications of thread extrusion or roll. If thread extrusion or roll is found, the gimbal nut must be replaced prior to further flight except ferry flight in accordance with the provisions of CAR 1.76.
Gimbal Nut
Axial Inch
Radial Inch
P/N's 27-165012-9, -10, -13, -14
0.035
0.030
P/N's 27-165012-17, -18
.050
.045
P/N's 27-175023-5, -6
.035
.030
(d) Every 600 hours' time in service after the modifications specified in paragraph (b) have been accomplished, the gimbal nuts must be removed from the screwjacks and visually inspected for damage. Ifthread extrusion or roll is found, the gimbal nut must be replaced prior to further flight except ferry flight in accordance with the provisions of CAR 1.76.
(e) On all F-27 type (including FH-227 models) aircraft, the repetitive inspection and lubrication intervals required by (c) may be increased as specified in Fairchild Hiller Service Bulletin 27-46 (F-27), dated April 4, 1967, and 27-3 (FH-227), dated April 4, 1967, or later revisions approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, when the improved flap gimbal nut and actuating shaft are incorporated in accordance with these service bulletins, or equivalent modification approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region. If wear is found exceeding the limits specified in these Service Bulletins, or if thread extrusion or roll is found, the gimbal nut must be replaced before further flight with an unused part of the same part number, or an equivalent part approvedby the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, except that the airplane may be flown in accordance with FAR 21.197 to a base where the replacement can be made.
(f) Upon request of the operator, an FAA maintenance inspector, subject to approval of the Chief, Engineering and Manufacturing Branch, FAA Eastern Region, may adjust the repetitive inspection intervals specified in this AD to permit compliance at an established inspection period of the operator if the request contains substantiating data to justify the increase for such operator.
(Fairchild Service Bulletin 27-18A dated October 27, 1959, partially covers the subject of paragraph (a).)
This supersedes AD 59-26-4.
This directive effective July 13, 1961.
Revised August 19, 1961.
Revised September 6, 1961.
Revised October 20, 1966.
Revised August 17, 1967.