AD 75-16-15 ACTIVE

75-16-15 BRITISH AIRCRAFT CORPORATION: Amendment 39-2288. Applies to BAC Model 1-11, 200 and 400 Series airplanes, except those which have been modified in accordance with Dunlop Modification C.1559, part (b) to incorporate the strengthened filter housing, P/N ACM.27656.

Compliance is required as indicated.

To prevent failure of the handbrake control valve filter housing, accomplish the following:

(a) For handbrake control valves, P/N AC 61772, prior to the accumulation of 7,000 total landings, or within the next 25 landings after the effective date of this AD, whichever occurs later, unless already accomplished within the last 350 landings -

(1) Clean the filter housing on the handbrake control valve, P/N AC 61772;

(2) With the No 2 hydraulic system pressurized to 3,000 psi, inspect the face of the filter housing, P/N ACM. 23102 for hydraulic fluid leakage and distortion; and

(3) If leakage or distortion is found, before further flight, remove the handbrake control valve from service and comply with paragraph (d).

(b) For handbrake control valves, P/N AC 61772, except those which have been modified in accordance with Dunlop Modification C.1559, part (a), prior to the accumulation of 9,500 total landings, or within the next 500 landings after the effective date of this AD, whichever occurs later, remove the handbrake control valve from service, and comply with paragraph (d).

(c) For handbrake control valves, P/N AC 61772, which have been modified in accordance with Dunlop Modification C.1559, part (a), prior to the accumulation of 12,000 total landings (including landings before modification), or within the next 500 landings after the effective date of this AD, whichever occurs later, remove the handbrake control valve from service, and comply with paragraph (d).

(d) Replace handbrake control valves removed as a result of the action required by paragraphs (a)(3), (b), or (c) of this AD with any of the following:

(1) Serviceable handbrake control valves, P/N AC 61772, which have accumulated less than 9,500 landings since new and continue to comply with paragraphs (a) and (b);

(2) Serviceable handbrake control valves, P/N AC 61772, which have been modified in accordance with Dunlop Modification C.1559, part (a) and have accumulated less than 12,000 landings since new and continue to comply with paragraphs (a) and (c); or

(3) Serviceable handbrake control valves, P/N AC 61772, which have had the old type filter housing, P/N ACM. 23102 replaced with the new strengthened filter housing, P/N ACM. 27656 in accordance with Dunlop Modification C.1559, part (b).

(e) For the purpose of complying with this AD, subject to acceptance by the assigned FAA Maintenance Inspector, the number of landings may be determined by dividing each airplane's hours' time in service by the operator's fleet average time from takeoff to landing for the BAC 1-11 airplane.

(Dunlop Alert Service Bulletin No. 29-A131,dated December 16, 1971, Dunlop Service Bulletin No. 29-131, dated December 20, 1971; and Revision 1, dated January 7, 1972; and BAC 1-11 Alert Service Bulletin No. 32-A-PM 5102, dated July 14, 1972, cover this same subject).

This amendment becomes effective August 28, 1975.