# AD 78-13-07: Trailing Edge Flap - Type: Airworthiness directive - Status: Current - Products: Boeing 737-100 Series, 737-200 Series, 737-200C Series, 737-300 Series, 737-400 Series, 737-500 Series, 737-600 Series, 737-700 Series and 737-800 Series - Effective: July 12, 1978 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Large airplane - Amendment: 39-3253 - Registered aircraft: 823 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/BBE6598261E92E19862568390053247E.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/78-13-07 ## The airworthiness directive 78-13-07 BOEING: Amendment 39-3253. Applies to inboard and outboard flap tracks of the outboard trailing edge flap installation identified in Boeing Service Bulletin Numbers 737-57-1082, Revision 4, or later FAA approved revisions, and 737-57-1084, Revision 2, or later FAA approved revisions, respectively, of all Boeing Model 737 series airplanes, including military type T43A airplanes, certificated in all categories. Compliance required as indicated. To detect cracks in the aft portion of the inboard and outboard flap tracks of the outboard trailing edge flap installation accomplish the following: A. Inspect the inboard and outboard tracks in accordance with paragraph B of this AD as follows: 1. Inboard tracks: Unless accomplished within the last 600 landings prior to the effective date of this AD, within the next 600 landings from the effective date of this AD or prior to the accumulation of 4,000 landings whichever occurs later. 2. Outboard tracks: Unless accomplished within the last 300 landings prior to the effective date of this AD, within the next 900 landings from the effective date of this AD or prior to the accumulation of 7,000 landings, whichever occurs later. If cracks are detected replace the track or repair per paragraph D of this AD. If cracks are not found, reinspect per paragraph C of this AD. B. Penetrant or magnetic particle inspect the applicable tracks in accordance with Boeing Service Bulletin Numbers 737-57-1082, Revision 4, or later FAA approved revisions, and 737-57-1084, Revision 2, or later FAA approved revisions, or in a manner approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region. C. Repeat the inspections in accordance with paragraph B of this AD at intervals not to exceed 1200 landings, except as required by paragraph D for repaired tracks. D. Repair cracked tracks in accordance with Boeing Service Bulletin Numbers 737-57-1082, Revision 4, or 737-57-1084,Revision 2, or later FAA approved revisions, as applicable, or in a manner approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region. Repaired tracks are to be penetrant or magnetic particle inspected at intervals not to exceed: 1. 1,200 landings for tracks with repaired lower flange edges by blendout. 2. 1,000 landings for tracks with cracks stop drilled in thin small portion of the flange. 3. 1,000 landings - for tracks with one web cracked between two adjacent holes in the area forward of aft fastener hole. 4. 500 landings - for tracks with one web cracked beyond two adjacent holes in the area forward of aft fastener hole. 5. 20 landings - for tracks with one web cracked and the crack propagating down from the aft fastener hole. Tracks with cracks other than those specified above, must be replaced prior to further flight. E. Replacement of the tracks affected by this AD with improved tracks identified in paragraphs Cof Boeing Service Bulletin Numbers 737-57-1082, Revision 4, or later FAA approved revisions, and 737-57-1084, Revision 2, or later FAA approved revisions, or equivalent approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region, constitutes terminating action for this AD. F. For the purpose of complying with the Airworthiness Directive, with approval of the assigned FAA maintenance inspector, the number of landings may be determined by dividing each airplane's hours time-in-service by the operator's Boeing Model 737 fleet average time from takeoff to landing. G. Airplanes may be flown to a maintenance base for repairs or replacement in accordance with FAR 21.197. H. Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Engineering and Manufacturing Branch, FAA Northwest Region, may adjust the repetitive inspection intervals in this AD, if the request contains substantiating data to justify the increasefor that operator. 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 Boeing Commercial Airplane Company, P.O. Box 3707, Seattle, Washington 98124. These documents may also be examined at FAA Northwest Region, 9010 East Marginal Way South, Seattle, Washington 98108. This AD supersedes AD 75-07-11, Amendment 39-2145. This amendment becomes effective July 12, 1978. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A16WE](https://openairdocs.org/tcds/A16WE): The Boeing Company; names 9 of 17 models: 737-500 Series, 737-100 Series, 737-200C Series, 737-800 Series, 737-300 Series, 737-200 Series, 737-700 Series, 737-400 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: 823 (823 by airframe model, 0 by engine model) - Makers: Boeing 823 Models with the most aircraft: - [Boeing 737-823](https://openairdocs.org/model/boeing-737-823): 278 aircraft (airframe model) - [Boeing 737-800](https://openairdocs.org/model/boeing-737-800): 139 aircraft (airframe model) - [Boeing 737-824](https://openairdocs.org/model/boeing-737-824): 135 aircraft (airframe model) - [Boeing 737-832](https://openairdocs.org/model/boeing-737-832): 73 aircraft (airframe model) - [Boeing 737-890](https://openairdocs.org/model/boeing-737-890): 60 aircraft (airframe model) - [Boeing 737-724](https://openairdocs.org/model/boeing-737-724): 36 aircraft (airframe model) - [Boeing 737-790](https://openairdocs.org/model/boeing-737-790): 14 aircraft (airframe model) - [Boeing 737-752](https://openairdocs.org/model/boeing-737-752): 13 aircraft (airframe model) - [Boeing 737-400](https://openairdocs.org/model/boeing-737-400): 8 aircraft (airframe model) - [Boeing 737-852](https://openairdocs.org/model/boeing-737-852): 7 aircraft (airframe model) - [Boeing 737-500](https://openairdocs.org/model/boeing-737-500): 6 aircraft (airframe model) - [Boeing 737-436](https://openairdocs.org/model/boeing-737-436): 6 aircraft (airframe model) - [Boeing 737-700](https://openairdocs.org/model/boeing-737-700): 5 aircraft (airframe model) - [Boeing 737-300](https://openairdocs.org/model/boeing-737-300): 4 aircraft (airframe model) - [Boeing 737-883](https://openairdocs.org/model/boeing-737-883): 4 aircraft (airframe model) - [Boeing 737-205](https://openairdocs.org/model/boeing-737-205): 3 aircraft (airframe model) - [Boeing 737-490](https://openairdocs.org/model/boeing-737-490): 3 aircraft (airframe model) - [Boeing 737-484](https://openairdocs.org/model/boeing-737-484): 3 aircraft (airframe model) - [Boeing 737-732](https://openairdocs.org/model/boeing-737-732): 3 aircraft (airframe model) - [Boeing 737-524](https://openairdocs.org/model/boeing-737-524): 3 aircraft (airframe model) All 40 models: https://openairdocs.org/ad/78-13-07/models.md Every aircraft: https://openairdocs.org/ad/78-13-07/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.