AD 90-06-13

90-06-13 HONEYWELL INC., SPERRY COMMERCIAL FLIGHT SYSTEMS DIVISION: Amendment 39-6538. Docket No. 90-NM-28-AD.

Applicability: Honeywell Model VG-14A vertical gyro, part number 7000622-901, with serial numbers listed in Honeywell Alert Service Bulletin 21-1989-191, Revision 1, dated November 20, 1989.

Compliance: Required as indicated, unless previously accomplished.

NOTE: These components are known to be installed in, but not limited to, Cessna Models 550/551, S550, 560, 650; Beech Models KA300, KA-1900, KA-200; Casa Model C-212-300; Grumman Model TC-4C; British Aerospace Model Jetstream 31; and de Havilland Models DHC-8-100 and -300 series airplanes.

To prevent erroneous attitude display and erratic function of the autopilot, accomplish the following:

A. Within 60 days after the effective date of this AD, inspect the Model VG-14A vertical gyros to determine the serial number.

1. If the vertical gyros have serial numbers listed in Table 1 of Honeywell Alert Service Bulletin 21-1989-191, Revision 1, dated November 20, 1989, and have the letter "D" marked out on the modification status plate, no further action is required, and the airplane may be returned to service.

2. If the vertical gyros have serial numbers listed in Table 1 of Honeywell Alert Service Bulletin 21-1989-191, Revision 1, dated November 20, 1989, and do not have the letter "D" marked out on the modification status plate, prior to further flight, remove the gyro, replace the liquid levels, test, and verify operation, in accordance with the procedures specified in paragraph 2., Accomplishment Instructions, of the service bulletin.

B. An alternate means of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Los Angeles Aircraft Certification Office, FAA, Northwest Mountain Region.

NOTE: The request should be forwarded through an FAA Principal Maintenance Inspector(PMI), who will either concur or comment, and then send it to the Manager, Los Angeles Aircraft Certification Office, FAA, Northwest Mountain Region.

C. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD.

All persons affected by this directive who have not already received the appropriate service information from the manufacturer may obtain copies upon request to Honeywell Inc., Business/Commuter Aviation Operation, Sperry Commercial Flight Systems Division, P.O. Box 29000, Phoenix, Arizona 85038; Attn: Product Support. This information may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 17900 Pacific Highway South, Seattle, Washington, or at the Los Angeles Aircraft Certification Office, FAA, Northwest Mountain Region, 3229 East Spring Street, Long Beach, California 90806-2425.

This AD supersedes AD 90-03-02, Amendment 39-6478.

This amendment (39-6538, AD 90-06-13) becomes effective on March 30, 1990.