AD 76-21-03

76-21-03 GRUMMAN AMERICAN: Amendment 39-2746. Applies to Model G-164 airplanes certificated in all categories incorporating Frenco Co. main landing gear struts P/N 1428, installed in accordance with STC SA647WE.

Compliance required as indicated.

To prevent possible hazards associated with main landing gear strut failures, accomplish the following:

(a) Within the next 100 landings after the effective date of this airworthiness directive, unless accomplished within the last 1900 landings, and thereafter at intervals not to exceed 2000 landings from the last inspection, remove the main gear struts, Frenco Co. P/N 1428, and inspect the struts for cracks using dye penetrant and a glass of at least 10 power or magnetic particles inspection.

"Note: During the inspection required by paragraph (a) particular attention should be directed to the upper bend radius, and fuselage attachment area."

(b) If cracks are found, before further flight, replace the cracked strut with an unused strut of the same part number.

(c) For the purpose of complying with this airworthiness directive, subject to the acceptance by the assigned FAA maintenance inspector, the number of landings may be determined by dividing each airplane's hours' time in service by the operator's fleet average time from takeoff to landing for the airplane type.

(d) Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Aircraft Engineering Division, FAA Western Region may adjust the repetitive inspection interval 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 that operator.

(e) Equivalent inspection procedures or parts may be used when approved by the Chief, Aircraft Engineering Division, FAA Western Region.

This amendment becomes effective October 20, 1976.