61-26-03 PIAGGIO: Amdt. 378 Part 507 Federal Register December 15, 1961. Applies to Models P.136- L1 and P.136-L2 Aircraft, Serial Numbers 196 Through 242.
Compliance required within the next 25 hours' time in service after the effective date of this AD.
The existing fuel vent line is provided with vent holes that are located inside the hull to provide venting in the event of blockage of the external vent outlet by ice or other foreign matter. As a result, fuel and fuel vapor have been detected within the hull constituting a fire and explosion hazard. These vent holes must, therefore, be sealed and other vent antiicing means provided as follows:
(a) Install one Mil H-5511 hose or equivalent, 3/4-inch I.D. by 5/8-inch long, and one clamp, AN 737-TW38 or equivalent, over holes in the outboard end of the fuel tank vent line. Sleeve may be slit if necessary but slit must not be over any hole.
(b) Install one Piaggio fuel vent anti-icing "bump" or equivalent.
(c) Apply anonfuel or water soluble, noncorrosive to aluminum sealing compound to the flange of the anti-icing "bump" and rivet "bump" to the skin forward of the fuel vent outlet using eight AN 470AD4-2, or equivalent, rivets. "Bump" flange should be about 1/8-inch forward of vent outlet flange. "Bump" longitudinal centerline must coincide with fuel vent outlet centerline and be level when aircraft is level. "Bump" must be oriented so that the thick end is forward.
This directive effective January 16, 1962.