AD 78-02-02

78-02-02 HUGHES HELICOPTERS: Amendment 39-3127. Applies to Model 269 Series helicopters, certificated in all categories including Model TH-55A.

Compliance is required as indicated, unless already accomplished.

To prevent failure of the tail rotor control pedals, accomplish the following:

(a) Within the next 100 hours time in service from the effective date of this AD, unless already accomplished, and thereafter at intervals not to exceed 100 hours time in service perform the following:

(1) On all models visually inspect the pilots' pedal arms P/N 269A7336 for cracks and corrosion in accordance with service information notice (SIN) N-121.1, Part I, Paragraph (b).

(i) If visual inspection reveals evidence of incipient cracks, further inspect with dye penetrant and if confirmed replace with a serviceable pedal arm P/N 269A7336 before further flight.

(ii) If corrosion is found, remove the corrosion in accordance with SIN N-121.1 before further flight.(iii) After corrosion removal of (1)(ii) above, inspect the wall thickness of the pedal arm in the areas of corrosion removal. If the wall thickness in the cylindrical section is less than .10 inches replace the pedal arm P/N 269A7336 with a serviceable pedal arm before further flight. If the corrosion removal on the pedal arm above the cylindrical section exceeds .005 inches in depth replace the pedal arm P/N 269A7336 with a serviceable pedal arm before further flight.

(2) On Models 269A, A-1, and TH-55A, visually inspect the copilots' pedal arms P/N 269A7336 in accordance with paragraph (a)(1) above.

(3) On Models 269B and C, remove the copilots' pedal arms P/N 269A7330 from the pedal sockets P/N 269A9973 or P/N 269A7334 and visually inspect for cracks and corrosion in accordance with SIN N-121.1, Part I, Paragraph (d).

(i) If visual inspection reveals evidence of incipient cracks, further inspect with dye penetrant in accordance with SIN N-121.1 and ifconfirmed replace with a serviceable part or parts before further flight.

(ii) If corrosion is found, remove the corrosion in accordance with SIN N121.1 before further flight.

(iii) After corrosion removal of (3)(ii) above, inspect the wall thickness in the areas of corrosion removal. If the wall thickness of the pedal arm is less than .13 inches replace the pedal arm P/N 269A7330 before further flight. If the wall thickness of the socket is less than .10 inches replace the socket P/N 269A9973 or P/N 269A7334 before further flight.

(b) Within the next 100 hours time in service, from the effective date of this AD unless already accomplished, and thereafter at intervals not to exceed 100 hours time in service, torque the pedal arm and/or socket bushing nuts to the limits specified by SIN N-121.1.

(c) On the 269B and 269C helicopters only, within the next 100 hours time in service, from the effective date of this AD unless already accomplished, measure the copilots' pedal arm wall thickness above the quick release pin hole. If the wall thickness is less than 0.130 inches replace the pedal arm P/N 269A7330 before further flight.

(d) On all Models except 269C, within the next 100 hours time in service, from the effective date of this AD unless already accomplished, rework the pilots' and copilots' left hand pedal arm and or sockets in accordance with SIN N-121.1 Part II.

(e) Hughes service information notice (SIN) N-121.1, dated October 3, 1977, or later FAA approved revisions shall be used for compliance where indicated in this AD except for alternate inspection and rework methods approved under Paragraph (f).

(f) Equivalent inspections, and reworks may be approved by Chief, Aircraft Engineering Division, FAA Western Region, Los Angeles, California.

This amendment becomes effective January 24, 1978.