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Federal Register Information
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
AD 64-05-06
Airworthiness Directives; Universal Model GC-1B Aircraft
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Preamble Information
AGENCY: Federal Aviation Administration, DOT
DATES: Effective February 27, 1964.
Regulatory Information
64-05-06 UNIVERSAL: Amdt. 690 Part 507 Federal Register February 27, 1964. Applies to All Model (Globe) GC-1B Aircraft and Their Conversions With Standard Engine Mount P/N 11-710-2520.
Compliance required as indicated.
There have been instances of failure through internal corrosion of the upper left and right hand members of the engine mount assembly, the point of failure being just above the weld junction with the horizontal members of the engine mount. To preclude the possibility of further failures, which could result in the loss of the engine, accomplish the following inspection within 30 days from the effective date of this AD and thereafter at every periodic (annual) inspection.
(a) Examine the engine mount members for evidence of rust and/or "pin holing" by probing with an ice pick or an equivalent tool.
(b) If the tubular member appears solid from the inspection described in (a), remove the upper drive screw present in most engine mount legs, or drill a No. 37 size hole at this upper end of the engine mount member. Drill another No. 37 hole at the lower end of the member and check for the presence of rust, water or deterioration.
(c) Replace any engine mount member that has been found to be damaged from internal corrosion by welding in a new member of 7/8 x 0.035 inch 4130 steel heat treated to 85,000 p.s.i. yield. Drill No. 37 holes in each end of this new member. Fill any new or existing member with Lionoil (or equivalent slushing compound) and then drain. The No. 37 holes can be used for this purpose. After the slushing compound has been drained out of the member, plug the holes with drive screws, AN 535-4-3.
NOTE: No exact method exists in the field for measuring the wall thickness remaining at the lower end of the tube, or of determining the exact amount of wall deterioration through rusting, but a close visual inspection of the drilled hole coupled with the condition encountered (i.e., obvious presence of water or rust) will allow a reasonable judgment of the general condition. For example, after the hole is drilled, the presence of a heavy colloidal solution of rust in water would indicate the probability of serious deterioration. An air nozzle may be applied at the upper hole to facilitate the expelling of any moisture that may be present.
(Universal Aircraft Industries Customer Service Bulletin No. 38 covers this same subject.)
This directive effective February 27, 1964.
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