# AD 90-06-13: Vertical Gyro - Type: Airworthiness directive - Status: Current - Products: Bombardier DHC-8-101, DHC-8-102, DHC-8-103, DHC-8-106, DHC-8-301, DHC-8-311, DHC-8-315, Jetstream Series 3101, 550, 551, 560, 650 and 5 more - Effective: March 30, 1990 - Superseded by: Nothing supersedes this AD - Product type: Appliance - Amendment: 39-6538 - Docket: 90-NM-28-AD - Registered aircraft: 1,826 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/88E11013389A0B8A86256A450050463D.0001 - DRS record last changed: January 21, 2026 - Page: https://openairdocs.org/ad/90-06-13 ## The airworthiness directive 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. ## Affected data sheets (6) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A13NM](https://openairdocs.org/tcds/A13NM): De Havilland Aircraft of Canada Limited; names 7 of 16 models: DHC-8-101, DHC-8-102, DHC-8-103, DHC-8-106, DHC-8-301, DHC-8-311, DHC-8-315 - [TCDS A22CE](https://openairdocs.org/tcds/A22CE): Textron Aviation Inc.; names 3 of 6 models: S550, 550, 560 - [TCDS A24CE](https://openairdocs.org/tcds/A24CE): Textron Aviation Inc.; names 3 of 37 models: 200, 300, 1900 - [TCDS A21EU](https://openairdocs.org/tcds/A21EU): British Aerospace Regional Aircraft; names 1 of 3 models: Jetstream Series 3101 - [TCDS A27CE](https://openairdocs.org/tcds/A27CE): Textron Aviation Inc.; names 1 of 2 models: 551 - [TCDS A9NM](https://openairdocs.org/tcds/A9NM): Textron Aviation Inc.; names 1 of 1 models: 650 ## Registered aircraft it may apply to (OpenAirDocs) Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment. - Aircraft: 1,826 (1,826 by airframe model, 0 by engine model) - Makers: Cessna 1,425, Beech 366, Bombardier 15, Dehavilland 9, Boeing Of Canada/Dehav Div 6, Boeing 3, CASA 1, Textron 1 Models with the most aircraft: - [Cessna 560](https://openairdocs.org/model/cessna-560): 596 aircraft (airframe model) - [Cessna 550](https://openairdocs.org/model/cessna-550): 500 aircraft (airframe model) - [Beech 200](https://openairdocs.org/model/beech-200): 234 aircraft (airframe model) - [Cessna 650](https://openairdocs.org/model/cessna-650): 201 aircraft (airframe model) - [Beech 300](https://openairdocs.org/model/beech-300): 125 aircraft (airframe model) - [Cessna S550](https://openairdocs.org/model/cessna-s550): 94 aircraft (airframe model) - [Cessna 551](https://openairdocs.org/model/cessna-551): 34 aircraft (airframe model) - [Bombardier DHC-8-315](https://openairdocs.org/model/bombardier-dhc-8-315): 15 aircraft (airframe model) - [Beech 1900](https://openairdocs.org/model/beech-1900): 7 aircraft (airframe model) - [Dehavilland DHC-8-106](https://openairdocs.org/model/dehavilland-dhc-8-106): 4 aircraft (airframe model) - [Boeing DHC-8-102](https://openairdocs.org/model/boeing-dhc-8-102): 3 aircraft (airframe model) - [Boeing Of Canada/Dehav Div DHC-8-311](https://openairdocs.org/model/boeing-of-canada-dehav-div-dhc-8-311): 3 aircraft (airframe model) - [Boeing Of Canada/Dehav Div DHC-8-106](https://openairdocs.org/model/boeing-of-canada-dehav-div-dhc-8-106): 2 aircraft (airframe model) - [Dehavilland DHC-8-103](https://openairdocs.org/model/dehavilland-dhc-8-103): 2 aircraft (airframe model) - [Dehavilland DHC-8-315](https://openairdocs.org/model/dehavilland-dhc-8-315): 2 aircraft (airframe model) - [Boeing Of Canada/Dehav Div DHC-8-102](https://openairdocs.org/model/boeing-of-canada-dehav-div-dhc-8-102): 1 aircraft (airframe model) - [Textron 560](https://openairdocs.org/model/textron-560): 1 aircraft (airframe model) - [CASA 300](https://openairdocs.org/model/casa-300): 1 aircraft (airframe model) - [Dehavilland DHC-8-102](https://openairdocs.org/model/dehavilland-dhc-8-102): 1 aircraft (airframe model) All 20 models: https://openairdocs.org/ad/90-06-13/models.md Every aircraft: https://openairdocs.org/ad/90-06-13/aircraft.md Its text cites no advisory circulars or STCs. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.