AD 75-19-04

75-19-04 RAVEN: Amendment 39-2363. Raven Model S-40A, S-50A, S-55A, S-60A, and RX-6 Hot Air Balloons:

Applies to Rego 7553S series blast valves installed on all models of the Raven hot air balloons certificated in all categories.

Compliance required as indicated below after the effective date of this AD unless already accomplished.

To prevent failures of the "O" ring on the valve stem; valve seat washer loosening; or valve actuating handle rollpin becoming dislodged, accomplish the following or an equivalent modification approved by the Chief, Engineering and Manufacturing Branch, FAA Rocky Mountain Region.

Within the next 25 hours time in service unless already accomplished within the last 25 hours time in service, accomplish Paragraph a, b, c, and d. Paragraph "a" and "c" are to be accomplished thereafter at each 100 hours time in service or at intervals not to exceed 12 calendar months from the last inspection, whichever comes first.

a. Remove the valveactuating lever rollpin P/N 7553S-8 from actuating lever. (Be careful to remove any burrs in the stem area around the rollpin hole before removing the valve stem P/N 7553S-1 from the bonnet P/N 7553-5). Replace the "O" ring stem seal with a new Rego "O" ring P/N 1421.7. Lubricate the new "O" ring with Orange Solid Oil (Rego P/N 5555GS) or unmedicated Vaseline lubricant before reassembly. Other lubricants may cause shrinkage of the "O" ring.

b. Check the torque of the valve seat retaining screw to 8 to 10 in-lbs in the counter-clockwise (loosening) direction. If it turns, the screw must be removed, cleaned of lubricant and reinstalled using MIL-S 22473 high strength thread locking compound, or equivalent. Recheck torque after thread locking compound has cured.

CAUTION: Do not permit the thread locking compound to adhere to the rubber seating surface.

c. Reinstall valve actuating lever on the valve body with rollpin, P/N 7553S-8. Install a number three machine screw and stop nut or a 3/32 inch stainless steel cotter pin or .040 inch diameter safety wire through the hole in the rollpin, holding the actuating handle to the valve body and secure.

d. Appropriate maintenance records must be kept in accordance with FAR 91.173.

This amendment becomes effective on September 17, 1975.