# AD 90-17-17: Inertial Reference Units - Type: Airworthiness directive - Status: Current - Products: Airbus A300 B4-601, A300 B4-603, A300 B4-605R, A300 B4-620, A300 B4-622R, A300 F4-605R, A300 F4-622R, A310-203, A310-221, A310-222, A310-304, A310-322 and 2 more - Effective: September 21, 1990 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Large airplane - Amendment: 39-6704 - Docket: 90-NM-31-AD - Registered aircraft: 122 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/4407D6EBADFEAAD98625695B0066A9E7.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/90-17-17 ## The airworthiness directive 90-17-17 AIRBUS INDUSTRIE: Amendment 39-6704. Docket No. 90-NM-31-AD. Applicability: Model A310 and A300-600 series airplanes, equipped with Litton LTN 90 or LTN 90-100 Inertial Reference Units, certificated in any category. Compliance: Required within 45 days after the effective date of this AD, unless previously accomplished. To prevent the loss of accurate attitude and heading information, accomplish the following: A. Remove the three inertial reference units (IRU), modify the wiring in Zone 121, and install modified IRU's, in accordance with the following service bulletins: AIRPLANE MODEL SERVICE BULLETIN A310 A310-34-2052, Revision 1, dated December 7, 1989 A300-600 A300-34-6029, Revision 1, dated December 7, 1989 NOTE: These service bulletins reference Litton Service Bulletins 34-90-102 and 34-90-98 for additional instructions. 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, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate. NOTE: The request should be submitted directly to the Manager, Standardization Branch, ANM-113, and a copy sent to the cognizant FAA Principal Inspector (PI). The PI will then forward comments or concurrence to the Manager, Standardization Branch, ANM-113. 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 documents from the manufacturer may obtain copies upon request to Airbus Industrie, Airbus Support Division, Avenue Didier Daurat, 31700 Blagnac France. These documents may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 17900 Pacific Highway South, Seattle, Washington, or the Standardization Branch, Marginal Way South, Seattle, Washington. This amendment (39-6704, AD 90-17-17) becomes effective on September 21, 1990. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A35EU](https://openairdocs.org/tcds/A35EU): Airbus SAS; names 14 of 17 models: A310-203, A300 B4-622R, A300 F4-605R, A300 B4-601, A310-221, A300 B4-603, A310-324, A300 F4-622R… ## 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: 122 (122 by airframe model, 0 by engine model) - Makers: Airbus Industrie 74, Airbus 48 Models with the most aircraft: - [Airbus Industrie A300 F4-605R](https://openairdocs.org/model/airbus-industrie-a300-f4-605r): 36 aircraft (airframe model) - [Airbus A300 F4-622R](https://openairdocs.org/model/airbus-a300-f4-622r): 31 aircraft (airframe model) - [Airbus Industrie A300 F4-622R](https://openairdocs.org/model/airbus-industrie-a300-f4-622r): 21 aircraft (airframe model) - [Airbus A300 B4-622R](https://openairdocs.org/model/airbus-a300-b4-622r): 11 aircraft (airframe model) - [Airbus Industrie A300 B4-622R](https://openairdocs.org/model/airbus-industrie-a300-b4-622r): 10 aircraft (airframe model) - [Airbus A300 F4-605R](https://openairdocs.org/model/airbus-a300-f4-605r): 6 aircraft (airframe model) - [Airbus Industrie A300 B4-605R](https://openairdocs.org/model/airbus-industrie-a300-b4-605r): 3 aircraft (airframe model) - [Airbus Industrie A310-203](https://openairdocs.org/model/airbus-industrie-a310-203): 2 aircraft (airframe model) - [Airbus Industrie A310-222](https://openairdocs.org/model/airbus-industrie-a310-222): 2 aircraft (airframe model) All 9 models: https://openairdocs.org/ad/90-17-17/models.md Every aircraft: https://openairdocs.org/ad/90-17-17/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.