AD 76-20-04

76-20-04 SWEARINGEN : Amendment 39-2735 as amended by Amendment 39-3348. Applies to all Model SA226-T, SA226-AT, and SA226-TC airplanes with Serial Numbers as follows:

Model SA226-T: T201 through T274. Model SA226-AT: AT001 through AT054. Model SA226-TC: TC201 through TC228E.

Within the next 25 hours time in service after the effective date of this airworthiness directive and within each subsequent 50 hours of time in service, inspect the left hand and right hand wheel wells for evidence of fuel or hydraulic leaks as follows:

A. Hydraulic System 1. Inspect the hydraulic power pack area in the left hand wheel well and all hydraulic lines in both landing gear wheel wells for condition or hydraulic leakage. Special attention should be given to the hydraulic gage line, P/N 27-81006-37, 731, 749, and 775, particularly in the area of bends.

2. Use either engine to pressurize the system to 2000 +psi and inspect the hydraulic lines, fittings and other components in both left and right wheel wells for any signs of leakage, including fluid misting from a spraying-type leakage.

3. If damaged lines or hydraulic leaks are found, repair or replace in accordance with FAA-approved maintenance procedures before further flight.

B. Fuel System 1. By using airframe boost pump, pressurize and inspect fuel supply line aft of firewall and inside wheel wells for leakage.

2. If fuel leaks are found, repair in accordance with FAA-approved maintenance procedures before further flight.

C. Voluntary written reports on the results of the inspection conducted in accordance with Paragraphs A and B, either positive or negative, should be forwarded to the Chief, Aircraft Engineering and Manufacturing Branch, Federal Aviation Administration, Southwest Region, P.O. Box 1689, Fort Worth, Texas 76101. (Reporting approved by the Office of Management and Budget under OMB No. 04-R0174.)

D. Special flight permits may be issued pursuant to Sections 21.197 and 21.199 of the Federal Aviation Regulations to authorize flights to a base for accomplishment of the inspections required by this airworthiness directive.

E. After the effective date of this AD and as an alternate means of compliance:

1. If Swearingen Aviation Corporation Models SA226TC (applies to serial numbers TC-201 through TC-212), SA226T (applies to serial numbers T-201 through T-251, except T-249), and SA226AT (applies to serial numbers AT-001 through AT-033, except AT-025) airplanes are modified in accordance with Swearingen Aviation Corporation service bulletin SB 21-009 dated May 11, 1977, "Addition of Bleed Air Heat Exchangers"; and if Swearingen Aviation Corporation Models SA226TC (applies to serial numbers TC-201 through TC-228, except TC-227E and TC-228E), SA226T (applies to serial numbers T-201 through T-271), and SA226AT (applies to serial numbers AT-001 through AT-056) airplanes are modified in accordance with Swearingen Aviation Corporation service bulletin SB 54-003 dated April 28, 1977, "Improved Fire Resistance of the Fuel and Hydraulic Systems;" then the repetitive inspections specified in paragraphs A and B of this AD are no longer necessary.

2. Or, if modifications are made to the above airplane models in a manner approved by the Chief, Engineering and Manufacturing Branch, ASW-210, Southwest Region, then the repetitive inspections called for in paragraphs A and B of this AD are no longer necessary.

Amendment 39-2735 became effective October 11, 1976.

This amendment 39-3348 becomes effective on November 17, 1978.