# AD 90-18-04: Hydraulic Power Transfer Unit - Type: Airworthiness directive - Status: Current - Products: Boeing 767-200 Series and 767-300 Series - Effective: October 9, 1990 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Large airplane - Amendment: 39-6714 - Docket: 89-NM-211-AD - Registered aircraft: 228 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/FC8E77DB070647868625695F00702102.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/90-18-04 ## The airworthiness directive 90-18-04 BOEING: Amendment 39-6714. Docket No. 89-NM-211-AD. Applicability: All Model 767-200 and -300 series airplanes on which Production Revision Record (PRR) B-11777 has not been incorporated, certificated in any category. Compliance: Required within 18 months after the effective date of this AD, unless previously accomplished. To prevent loss of stabilizer trim and decreased pitch control authority, accomplish the following: A. For airplanes identified in Boeing Alert Service Bulletin 767-29A0039, dated May 11, 1989: Install the hydraulic power transfer unit system with its associated components in accordance with the procedures outlined in that service bulletin, or Revision 1, dated November 2, 1989. B. For all other airplanes: Install a hydraulic power transfer unit system with its associated components in accordance with the procedures approved by the Manager, Seattle Aircraft Certification Office, FAA, Transport Airplane Directorate; or in accordance with Boeing Alert Service Bulletin 767-29A0039, Revision 1, dated November 2, 1989. C. 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, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. NOTE: The request should be submitted directly to the Manager, Seattle ACO, and a copy sent to the cognizant FAA Principal Inspector (PI). The PI will then forward comments or concurrence to the Seattle ACO. D. 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 Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124. These documents may be examined at theFAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue SW, 5th Floor, Renton, Washington, or Seattle Aircraft Certification Office, 1601 Lind Avenue SW, 2nd Floor, Renton, Washington. This amendment (39-6714, AD 90-18-04) becomes effective on October 9, 1990. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A1NM](https://openairdocs.org/tcds/A1NM): The Boeing Company; names 2 of 5 models: 767-300 Series, 767-200 Series ## 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: 228 (228 by airframe model, 0 by engine model) - Makers: Boeing 228 Models with the most aircraft: - [Boeing 767-332](https://openairdocs.org/model/boeing-767-332): 46 aircraft (airframe model) - [Boeing 767-322](https://openairdocs.org/model/boeing-767-322): 36 aircraft (airframe model) - [Boeing 767-323](https://openairdocs.org/model/boeing-767-323): 27 aircraft (airframe model) - [Boeing 767-338](https://openairdocs.org/model/boeing-767-338): 13 aircraft (airframe model) - [Boeing 767-316](https://openairdocs.org/model/boeing-767-316): 12 aircraft (airframe model) - [Boeing 767-346](https://openairdocs.org/model/boeing-767-346): 11 aircraft (airframe model) - [Boeing 767-281](https://openairdocs.org/model/boeing-767-281): 9 aircraft (airframe model) - [Boeing 767-381](https://openairdocs.org/model/boeing-767-381): 8 aircraft (airframe model) - [Boeing 767-232](https://openairdocs.org/model/boeing-767-232): 6 aircraft (airframe model) - [Boeing 767-319](https://openairdocs.org/model/boeing-767-319): 6 aircraft (airframe model) - [Boeing 767-306](https://openairdocs.org/model/boeing-767-306): 5 aircraft (airframe model) - [Boeing 767-224](https://openairdocs.org/model/boeing-767-224): 5 aircraft (airframe model) - [Boeing 767-300](https://openairdocs.org/model/boeing-767-300): 5 aircraft (airframe model) - [Boeing 767-336](https://openairdocs.org/model/boeing-767-336): 4 aircraft (airframe model) - [Boeing 767-223](https://openairdocs.org/model/boeing-767-223): 3 aircraft (airframe model) - [Boeing 767-231](https://openairdocs.org/model/boeing-767-231): 3 aircraft (airframe model) - [Boeing 767-304](https://openairdocs.org/model/boeing-767-304): 3 aircraft (airframe model) - [Boeing 767-324](https://openairdocs.org/model/boeing-767-324): 3 aircraft (airframe model) - [Boeing 767-233](https://openairdocs.org/model/boeing-767-233): 2 aircraft (airframe model) - [Boeing 767-238](https://openairdocs.org/model/boeing-767-238): 2 aircraft (airframe model) All 33 models: https://openairdocs.org/ad/90-18-04/models.md Every aircraft: https://openairdocs.org/ad/90-18-04/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.