# AD 74-23-03: Auto Pack Trip System - Type: Airworthiness directive - Status: Current - Products: Boeing 727-100 Series, 727-100C Series, 727-200 Series, 727-200F Series, 727 Series and 727C Series - Effective: November 8, 1974 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Large airplane - Amendment: 39-2003 - Registered aircraft: 25 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/323641297CC6C523862568320056B5B4.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/74-23-03 ## The airworthiness directive 74-23-03 BOEING: Amendment 39-2003. Applies to all Model 727 Series Airplanes certificated in all categories and equipped with the Auto Pack Trip System. Compliance required as indicated unless already accomplished. To prevent the inadvertent trip of both air conditioning packs and the subsequent rapid loss of cabin pressurization, accomplish the following: (A) Within one calendar day after the effective date of this AD, as an interim action, during the first flight and on all subsequent flights until the action specified in paragraph (B) and (C) of this AD has been accomplished, control the Auto Pack Trip System in accordance with the information and procedures contained in Boeing 727 "Operations Manual Bulletin" Number 74-7 dated September 5, 1974; and (B) Within 100 hours time in service after the effective date of this AD, unless paragraph (C) is already accomplished, collar the Auto Pack Trip circuit breaker on the P6 panel and install one placard adjacent to thecircuit breaker and one adjacent to the Auto Pack Trip Switch which reads, "Auto Pack Trip Inoperative". (C) As terminating action of this AD, within the next 900 hours time in service after the effective date of this AD, modify the Auto Pack Trip System in accordance with the information contained in the following documents as applicable, or a method approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region: (1) Boeing Alert Service Bulletin 727-36-21 dated September 20, 1974, or later FAA approved revisions, applies to 727-200 series airplanes. (2) Boeing Service Bulletin 727-36-17, Revision 2, dated October 4, 1974, or later FAA approved revisions, applies to the following 727-100 series airplanes if Boeing Service Bulletin 727-36-17 original issue and Revision 1 have been incorporated: 727-116 S/N 19811 727-116C S/N 19813 and 19814 727-21 S/N 18992 thru 18999 727-21 S/N 19005 thru 19007 727-21 S/N 19035 thru 19038 727-21 S/N 19257 thru 19262 727-21C S/N 19134 thru 19137 (3) Boeing Service Bulletin 727-36-18, Revision 1, dated October 4, 1974, or later FAA approved revisions, applies to the following 727-100 series airplanes if Boeing Service Bulletin 727-36-18 has been incorporated: 727-155C S/N 19619 (4) Boeing Service Bulletin 727-36-22 dated October 4, 1974, or later FAA approved revisions, applies to the following 727-100 series airplanes: 727-17 S/N 20327 and 20328; S/N 20512 and 20513 727-41 S/N 20422 thru 20426 727-113C S/N 20343 727-1H2 S/N 20533 727-1F8 S/N 20421 727-C3 S/N 20418 thru 20420 The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this Directive who have not already received these documents from the manufacturer, may obtain copies upon request to the Boeing Commercial Airplane Company,P. O. Box 3707, Seattle, Washington 98124. These documents may be examined at FAA Northwest Region, 9010 East Marginal Way, Seattle, Washington 98108. This amendment becomes effective November 8, 1974. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A3WE](https://openairdocs.org/tcds/A3WE): The Boeing Company; names 6 of 6 models: 727-100 Series, 727 Series, 727-200 Series, 727-100C Series, 727-200F Series, 727C 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: 25 (25 by airframe model, 0 by engine model) - Makers: Boeing 25 Models with the most aircraft: - [Boeing 727-223](https://openairdocs.org/model/boeing-727-223): 9 aircraft (airframe model) - [Boeing 727-227](https://openairdocs.org/model/boeing-727-227): 4 aircraft (airframe model) - [Boeing 727-225](https://openairdocs.org/model/boeing-727-225): 2 aircraft (airframe model) - [Boeing 727-200F](https://openairdocs.org/model/boeing-727-200f): 1 aircraft (airframe model) - [Boeing 727-200](https://openairdocs.org/model/boeing-727-200): 1 aircraft (airframe model) - [Boeing 727-212](https://openairdocs.org/model/boeing-727-212): 1 aircraft (airframe model) - [Boeing 727-230](https://openairdocs.org/model/boeing-727-230): 1 aircraft (airframe model) - [Boeing 727-232](https://openairdocs.org/model/boeing-727-232): 1 aircraft (airframe model) - [Boeing 727-243](https://openairdocs.org/model/boeing-727-243): 1 aircraft (airframe model) - [Boeing 727-247](https://openairdocs.org/model/boeing-727-247): 1 aircraft (airframe model) - [Boeing 727-264](https://openairdocs.org/model/boeing-727-264): 1 aircraft (airframe model) - [Boeing 727-281](https://openairdocs.org/model/boeing-727-281): 1 aircraft (airframe model) - [Boeing 727-277](https://openairdocs.org/model/boeing-727-277): 1 aircraft (airframe model) All 13 models: https://openairdocs.org/ad/74-23-03/models.md Every aircraft: https://openairdocs.org/ad/74-23-03/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.