AD 62-04-01 ACTIVE

62-04-01 FAIRCHILD: Amdt. 399 Part 507 Federal Register February 17, 1962. Applies to all F-27 Series aircraft.

Compliance required as indicated.

Due to the failure of several main landing gear drag strut attaching bolts, the following is required on aircraft having accumulated 300 or more landings. (It will be necessary for operators to maintain a record of landings in order to ascertain compliance with this AD. If past records are unavailable, the number of landings prior to this AD may be estimated.)

(a) Within the next 50 landings after effective date of this AD unless already accomplished within the past 100 landings:

(1) Remove the bolts, Dowty P/N's 9017Y11 and 9027Y7, and inspect for cracks, using magnetic particle or dye penetrant methods, or FAA approved equivalents. Cracks emanate from the center grease hole and progress around the bolt circumference. Replace cracked bolts prior to further flight either with the original type bolts, nuts, and washers, or the following:

(i) For the upper bolt, P/N 9017Y11, substitute any one of the following or FAA-approved equivalent: Dowty bolt, P/N 200-021.064; NAS 630-38 bolt with one NAS 143-10C washer under the bolt head, one NAS 143-10 washer under the nut, and an AN-310-10 or AN320-10 nut; or Dowty bolt P/N 200021.267, with lock plate P/N 200021.255, washer P/N BS/SP13-Q, and nut P/N A.103-LS. Dowty lock plate P/N 200021.255 must be connected to Fairchild P/N 27-502033-11 with an AN 173-11A bolt and an AN365-1032 nut as shown in Fairchild Service Bulletin 32-44 revised January 23, 1962, or FAA-approved equivalent. Where an NAS 630-38 bolt is not available, longer NAS 630 bolt lengths may be used, with NAS 143-10 washers under the nut, provided proper clearances are maintained.

(ii) For the lower bolt, P/N 9027Y7, substitute either of the following, or FAA-approved equivalent: Dowty bolt, P/N 200-200042.627, with washer P/N BS/SP16-Q, nut P/N SP878-2, bushing P/N 200021.347, grease adapter P/N 200021.348, nipple P/N MS15001-1 and split pin P/N BS/SP.9C10 or cotter pin P/N AN381-4-22, installed in accordance with Fairchild Service Bulletin No. 32-44, revised January 23, 1962; or NAS 632-60 bolt with one NAS 143-12C washer under the bolt head and an AN310-12 or AN320-12 nut. Where an NAS 632-60 bolt is not available, longer NAS 632 bolt lengths may be used with NAS 143-12 washers under the nut provided proper clearances are maintained.

(2) Drill a 0.141-inch diameter hole for a cotter pin in the NAS bolts listed in (a)(i) and (ii). Coat each NAS bolt with MIL-G-3278A grease before installing, and tighten nut to fit snug.

(b) Oil NAS bolts daily with SAE 20 motor oil without removing.

(c) If NAS bolts are installed inspect using the magnetic particle or dye penetrant methods or FAA approved equivalents, and regrease every 300 landings from the date of installation. Replace cracked bolts in accordance with (a)(1).

(d) If no cracksare evident in the existing bolts, P/N's 9017Y11 and 9027Y7, they may be reinstalled. Thereafter, remove and inspect the bolts per (a)(1) at intervals of 150 landings from the date of reinstallation.

(e) If Dowty bolts, P/N 200021.064, or new original bolts, Dowty P/N 9017Y11 or 9027Y7 are used, further inspection is not required until the bolts have accumulated 300 landings. Thereafter, remove and inspect the bolts for cracks, using the magnetic particle or dye penetrant methods or FAA approved equivalent at intervals of 150 landings. Replace cracked bolts in accordance with (a)(1).

(f) If Dowty bolts, P/N 200021.267, are used, inspect bushing P/N 27-502046-3 or FS- 10381410-77 whichever is installed in the nacelle fitting P/N 27-502033-11, and the drag strut bushing P/N D7761Y7. If the bushing-bolt clearance does not exceed 0.004 inch, subsequent inspection of the bolts for cracks using the magnetic particle or dye penetrant methods or FAA approved equivalents shall be within 3,000 landings and every 300 landings thereafter. Replace cracked bolts in accordance with (a)(1). The bushings are to be inspected at each bolt inspection. If bolt-bushing clearance is more than 0.004 inch but less than 0.006 inch subsequent inspection of the bolts and bushings shall be within each 300 landings until the bushings are replaced. After replacement of the bushing the next repetitive inspection of the bolts and bushings shall be within 3,000 landings after installation of the bolts and thereafter within each 300 landings. Whenever the bushing-bolt clearance exceeds 0.006 inch replace the bushing prior to further flight except ferry flight in accordance with the provisions of CAR 1.75. Replace bushings with a bushing of the same part number or FAA approved equivalent.

(g) If Dowty bolts P/N 2.00042.627 are used, inspect bushings P/N 2.00021.347 and D9027Y8 which are installed in the drag strut fitting P/N 2.00021.345 or C9017Y9. If the bushing-bolt clearance doesnot exceed 0.0035 inch subsequent inspection of the bolts for cracks using the magnetic particle or dye penetrant methods or FAA approved equivalents shall be within 5,000 landings and every 300 landings thereafter. Replace cracked bolts in accordance with (a)(1). The bushings are to be inspected at each bolt inspection. If bolt-bushing clearance is more than 0.0035 inch but less than 0.006 inch subsequent inspection of the bolts and bushings shall be within each 300 landings until the bushings are replaced. After replacement of the bushing the next repetitive inspection of the bolts and bushings shall be within 5,000 landings after installation of the bolts and thereafter within each 300 landings. Whenever the bushing-bolt clearance exceeds 0.006 inch replace the bushing prior to further flight except ferry flight in accordance with the provisions of CAR 1.75. Replace bushings with a bushing of the same part number or FAA approved equivalent.

Upon request of the operator, an FAAmaintenance inspector, subject to prior 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 32-44, revised January 23, 1962, covers this subject.)

This supersedes AD 61-15-3.

This directive effective February 17, 1962.

Revised March 16, 1962.