AD 92-07-09

92-07-09 BOEING: Amendment 39-8205. Docket No. 91-NM-215-AD. Supersedes AD 90- 07-02, Amendment 39-6547.

Applicability: Model 737-300, -400, and -500 series airplanes; equipped with Sperry SP300 Autopilot Flight Control Computers and Mode Control Panels (MCP); certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent uncommanded changes to the target altitude displayed in the altitude window of the autopilot mode control panel (MCP), accomplish the following:

(a) For Model 737-300 series airplanes: Within 10 days after April 5, 1990 (the effective date of AD 90-07-02, Amendment 39-6547), incorporate the following procedures into the Limitations Section of the FAA-approved Airplane Flight Manual (AFM). This may be accomplished by inserting a copy of this AD in the AFM.

"Autopilot Limitations For airplanes with SP300 autopilot MCP. Flightcrews must use the following procedures:

1. Check MCPsettings after any electrical power interruptions. 2. Following change in ALT selection in the MCP window, check ALT display to ensure desired altitude is displayed. 3. Closely monitor altitude during all altitude changes to ensure that the autopilot captures and levels off at the desired altitude. NOTE: Standard 'callouts,' crew coordination, and cross-checking of MCP settings and flight instruments are necessary to detect any nonselected MCP display number changes."

(b) For all airplanes: Within 18 months after the effective date of this AD, modify the MCP in accordance with Boeing Alert Service Bulletin 737-22A1098, dated January 17, 1991.

(c) After accomplishment of paragraph (b) of this AD, remove the AFM limitation that is specified in paragraph (a) of this AD.

NOTE: For Model 737-400 and -500 series airplanes, this limitation was included in the amended type certificate, and must be deleted in accordance with this paragraph.

(d) An alternative method of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. The request shall be forwarded through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Seattle ACO.

(e) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the airplane to a location where the requirements of this AD can be accomplished.

(f) The modification shall be done in accordance with Boeing Alert Service Bulletin 737-22A1098, dated January 17, 1991. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington; or at the Office of the Federal Register, 1100 L Street NW., Room 8401, Washington, DC.

(g) This amendment becomes effective on May 4, 1992.