# AD 79-10-13: Door Lock Mechanism - Type: Airworthiness directive - Status: Current - Products: Boeing DC-9-11, DC-9-12, DC-9-13, DC-9-14, DC-9-15, DC-9-15F, DC-9-21, DC-9-31, DC-9-32, DC-9-32 (VC-9C), DC-9-32F, DC-9-32F (C-9A) and 10 more - Effective: September 13, 1979 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Large airplane - Amendment: 39-3554 - Registered aircraft: 99 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/AE564FF43FE8462386256E0C00738FFD.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/79-10-13 ## The airworthiness directive 79-10-13 MCDONNELL DOUGLAS: Amendment 39-3472 as amended by Amendment 39-3554. Applies to DC-9 Series and Military C-9 Series airplanes, certificated in all categories. Compliance is required as indicated. To detect fatigue cracks in the forward passenger entry door lock mechanism crank assembly parts, P/N 4918613-3 (crank) and P/N 4918613-5 (clevis) accomplish the following: (a) Within the next 3,500 landings after the effective date of this AD, or before accumulating 22,500 total landings whichever occurs later, comply with the applicable program of inspections and/or corrective actions in accordance with paragraphs (b) and (c) below: (b) Prior to disassembly, visually inspect the crank assembly P/N 4918613-1 for proper engagement of serrations. If the serrations of the -3 and/or -5 parts are observed to be riding on the unserrated surface of the mating -3 and/or -5 parts, replace both parts per the requirement of paragraph (c)(1)(i) and/or (c)(1)(ii) and/or (c)(1)(iii) of this AD. (c) If visual inspection of the P/N 4918613-1 crank assembly shows proper engagement of serrations, perform the dye penetrant inspections on the crank assembly parts, P/N 4918613-3 (crank) and P/N 4918613-5 (clevis), in accordance with the instructions contained in Paragraph 2 of McDonnell Douglas Service Bulletin 52-111, Revision 1, dated May 31, 1979. (1) If a crack(s) is found in the -3 crank and/or the -5 clevis or there is evidence, (abrasion, etc.), that a serrated part was riding on an unserrated surface of the mating face, before further flight: (i) replace the part(s) with an unmodified -3 crank and/or -5 clevis; or, (ii) replace the part(s) with a -3 crank and/or a -5 clevis modified in accordance with the instructions contained in Paragraph 2 of McDonnell Douglas Service Bulletin 52-111, Revision 1, dated May 31, 1979; or, (iii) replace the cracked part(s) with a new crank, P/N 4918613-11, and/or a new clevis, P/N 4918613-13, in accordance with the instructions contained in Paragraph 2 of McDonnell Douglas Service Bulletin 52-111, Revision 1, dated May 31, 1979. Note: Any combination of parts listed in subparagraphs (i), (ii) and (iii) is acceptable. (2) If no cracks are found and there is no evidence of a serrated part riding on the unserrated surface of the mating face; (i) reinstall the part; or, (ii) replace the part(s) per (c)(1)(i) and/or (c)(1)(ii) and/or (c)(1)(iii) above. (d) Reinstallation and/or replacement of parts in accordance with paragraphs (b), (c)(1) and (c)(2) constitutes terminating action for this AD. (e) Operators who have accomplished the objective of this AD prior to the effective date of this AD in a manner approved by the Chief, Aircraft Engineering Division, FAA Western Region are exempt from the provisions of this AD. (f) Alternative inspections, modifications or other actions which provide an equivalent level of safety may be used when approved by the Chief, Aircraft Engineering Division, FAA Western Region. (g) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of inspections and modifications required by this AD. (h) For the purpose of complying with this AD, subject to the acceptance by the assigned FAA Maintenance Inspector, the number of landings may be determined by dividing each airplane's hour's time in service by the operator's fleet average time from takeoff to landings for the airplane type. (i) Upon request of operator, an FAA maintenance inspector, subject to prior approval of the Chief, Aircraft Engineering Division, FAA Western Region may adjust the inspection interval specified in this AD to permit compliance at an established inspection period of the operator, if the request contains substantiating data to justify the increase for that operator. Amendment 39-3472 became effective June 20, 1979.This Amendment 39-3554 becomes effective September 13, 1979. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A6WE](https://openairdocs.org/tcds/A6WE): The Boeing Company; names 19 of 25 models: DC-9-12, DC-9-15F, DC-9-41, DC-9-13, DC-9-34F, DC-9-81 (MD-81), DC-9-33F, DC-9-83 (MD-83)… ## 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: 99 (99 by airframe model, 0 by engine model) - Makers: Mcdonnell Douglas 93, Douglas 6 Models with the most aircraft: - [Mcdonnell Douglas DC-9-83(MD-83)](https://openairdocs.org/model/mcdonnell-douglas-dc-9-83-md-83): 49 aircraft (airframe model) - [Mcdonnell Douglas DC-9-82(MD-82)](https://openairdocs.org/model/mcdonnell-douglas-dc-9-82-md-82): 22 aircraft (airframe model) - [Mcdonnell Douglas DC-9-87](https://openairdocs.org/model/mcdonnell-douglas-dc-9-87): 13 aircraft (airframe model) - [Mcdonnell Douglas DC-9-15F](https://openairdocs.org/model/mcdonnell-douglas-dc-9-15f): 3 aircraft (airframe model) - [Mcdonnell Douglas DC-9-33F](https://openairdocs.org/model/mcdonnell-douglas-dc-9-33f): 3 aircraft (airframe model) - [Douglas DC-9-83](https://openairdocs.org/model/douglas-dc-9-83): 1 aircraft (airframe model) - [Douglas DC9-15](https://openairdocs.org/model/douglas-dc9-15): 1 aircraft (airframe model) - [Douglas DC-9-15F](https://openairdocs.org/model/douglas-dc-9-15f): 1 aircraft (airframe model) - [Douglas DC-9-21](https://openairdocs.org/model/douglas-dc-9-21): 1 aircraft (airframe model) - [Douglas DC-9-32F](https://openairdocs.org/model/douglas-dc-9-32f): 1 aircraft (airframe model) - [Mcdonnell Douglas DC-9-32](https://openairdocs.org/model/mcdonnell-douglas-dc-9-32): 1 aircraft (airframe model) - [Mcdonnell Douglas DC-9-32F](https://openairdocs.org/model/mcdonnell-douglas-dc-9-32f): 1 aircraft (airframe model) - [Douglas DC-9-33F](https://openairdocs.org/model/douglas-dc-9-33f): 1 aircraft (airframe model) - [Mcdonnell Douglas DC-9-87 (MD-87)](https://openairdocs.org/model/mcdonnell-douglas-dc-9-87-md-87): 1 aircraft (airframe model) All 14 models: https://openairdocs.org/ad/79-10-13/models.md Every aircraft: https://openairdocs.org/ad/79-10-13/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.