# AD 78-09-05: Wing Spar Caps and Web Doublers - Type: Airworthiness directive - Status: Current - Products: Cessna 336, 337, 337A, 337B, 337C, 337D, 337E, 337F, 337G, 337H, M337B, P337H and 7 more - Effective: May 11, 1978 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Small airplane - Amendment: 39-3202 - Registered aircraft: 664 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/665E8515681004E086256A3400690BDF.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/78-09-05 ## The airworthiness directive 78-09-05 CESSNA: Amendment 39-3202. Applies to the following models and serial number airplanes certificated in all categories: MODELS SERIAL NUMBERS 336 336-0001 through 336-0195 337, 337A, 337B, T337B, 337C, T337C, 337D and T337D 337-0001 through 337-1193 337E, T337E, 337F, T337F, 337G, 337H and T337H 33701194 through 33701852 T337G and P337H P3370001 through P3370313 M337B All serial numbers Compliance: Required as indicated in accordance with Compliance Table I set forth in this AD or as otherwise set forth herein, unless already accomplished. To detect cracking of the wing front and rear spar lower caps, front spar web and web doubler - In accordance with instructions set forth herein and in Cessna Multi-Engine Service Letter ME78-2, dated February 13, 1978, or later revisions: I. At time intervals noted in Table I of this AD, inspect the right and left wing front and rear spar lower cap and front spar web and web doubler onairplanes having model and serial numbers shown below; TABLE 1 COMPLIANCE TIMES Airplane Type/ Operation Total Time in Service for each of the following: Inspection Times for Spar Cap - Inspections required by Paragraph I.A. Inspection Times for Front Spar Web - Inspections Required by Paragraph I.B. 1) Front Spar Lower Cap Initial Inspection in accordance with this AD Interval for Repetitive Inspections Initial Inspection Interval for Repetitive Inspections* 2) Rear Spar Lower Cap 3) Front Spar Web & Web Doubler Non-Pressurized (See Note 1) 0 to 4999 None None None None 5,000 & up Within 25 hours time-in-service after the effective date of this AD for those airplanes which have not yet been inspected in accordance with AD 76-10-11 or 73-04-02 or; within 500 hours time-in-service after the last inspection in accordance with AD 76-10-11 or 73-04-02. 500 hoursWithin 25 hours time-in-service after the effective date of this AD. 500 hours Pressurized (See Note 1) 0 to 9,999 None None None None 10,000 & up Within 25 hours time-in-service after the effective date of this AD for those airplanes which have not yet been inspected in accordance with AD 76-10-11 or 73-04-02 or; within 500 hours time-in-service after the last inspections in accordance with AD 76-10-11 or 73-04-02. 500 hours Within 25 hours time-in-service after the effective date of this AD. 500 hours NOTE 1: For those airplanes which have engaged in contour or terrain following operations at low altitudes, such as power/pipeline patrol, fish or game spotting, aerial applications, police patrol, live- stock management, etc., Cessna recommends and FAA strongly urges inspections at intervals shown to the right of this note. 0 to 2,999 3,000 & up None Within 25 hours time-in-service afterthe effective date of this AD for those airplanes which have not yet been inspected in accordance with the suggestion in AD 76-10-11 or 73-04-02 or, within 300 hours time- in-service after the last inspection in accordance with AD 76-10-11 or 73-04-02. None 300 hours None Within 25 hours time-in-service after the effective date of this AD. None 300 hours *After initial inspection in accordance with this AD the compliance time for repetitive inspections may be adjusted to allow compliance at the same time as the inspections required by paragraph 1A of this AD. A. Front and rear spar lower cap inspection; Model Serial Numbers 336 336-0001 through 336-0195 337, 337A, 337B, T337B, 337C, T337C, 337D, and T337D 337-0001 through 337-1193 337E, T337E, 337F, T337F, and 337G 33701194 through 33701548 T337G P3370001 through P3370138 M337B All serial numbers 1. Front spar lower cap inspection. a. Inspect three fastener holes on the left wing and three fastener holes on the right wing for wing spar cracks using eddy current inspection procedures outlined in the above noted Cessna Service Letter. Figure 1 shows the area involved and the three fasteners (two NAS 221 screws at W.S. 64.41 and the jack point bolt hole at W.S. 68.45) that are to be inspected. b. Remove the two NAS 221 screws at Wing Station 64.41 one at a time for this inspection and hold the boom fairing firmly against underlying thicknesses of material to insure proper eddy current probe depth settings during this inspection. A cross-section with the screws at W.S. 64.41 removed is shown in Figure 2. Figure 3 shows the spar assembly (less boom and wing skins) and the relationship of the lower cap to the other parts at the strut attachment. Figure 4 shows the spar cross-section thru the jack point bolt hole. c. If cracks are found in either the right or left wing front spar lower cap during any inspection required by this AD, prior to approving the airplane for return to service replace the front spar lower cap in both the right and left wing with new spar caps. 2. Rear spar lower cap inspection. a. Dye penetrant inspect the lower spar cap area between two and three inches (2nd rivet outboard of W.S. 66.00 rib) outboard of wing station 66.00 rib for spar cap cracks originating in the rivet hole in accordance with inspection provisions in the above noted Cessna Service Letter. Figures 5, 6 and 7 show the location of the area on the rear spar lower cap to be inspected. b. If cracks are found in either the right or left wing rear spar lower cap during any inspection required by this AD, prior to approving the airplane for return to service replace the rear spar lower cap in both the right and left wing. B. Front spar web and web doubler inspection; Model Serial Numbers 336 336-0001 through 336-0195 337, 337A, 337B,T337B, 337C, T337C, 337D and T337D 337-0001 through 337-1193 337E, T337E, 337F, T337F, 337G, 337H and T337H 33701194 through 33701852 T337G and P337H P3370001 through P3370313 M337B All serial numbers 1. Remove wing root access panels and wing root fairings. 2. Visually inspect the radii of both the spar web and web doubler for cracks in the shaded critical area shown in Figure 8 of this AD. 3. If cracks are found in either the right or left wing front spar web or web doubler during any inspection required by this AD, prior to approving the airplane for return to service, replace the discrepant components. II. Airplanes found to have cracked spar caps, webs or web doublers during inspections required by this AD may be flown in accordance with FAR 21.197 to a base where the component replacement can be accomplished. III. Accomplish the repetitive inspections made mandatory by this AD on those spar caps, webs and web doublers replaced in accordance with this AD upon accumulation of the total times-in-service shown in Table I of this AD. Repetitive inspections "strongly urged" via Note 1 in Table I of this AD should also be accomplished on spar caps, webs and web doublers replaced in accordance with this AD upon accumulation of the total times-in-service shown in Note 1, Table I, of this AD. IV. Notify in writing the Chief, Engineering and Manufacturing Branch, FAA, Central Region, of the location and length of any crack found during inspections required by this AD and also the total time in service of the component at the time the crack was discovered. (Reporting approved by the Office of Management and Budget under OMB NO. 04-R0174.) V. The time interval for repetitive inspections required by this AD, after compliance with initial inspection requirements, can be adjusted up to 25 hours to allow accomplishment of these inspections at regular scheduled maintenance periods. VI. Equivalent methods of compliance with this AD must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region. This AD supersedes AD 76-10-11, Amendment 39-2621 (41 FR 22045, 22046, 22047 and 22048). This Amendment becomes effective May 11, 1978. ## Affected data sheets (2) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A6CE](https://openairdocs.org/tcds/A6CE): Textron Aviation Inc.; names 18 of 19 models: 337, T337B, T337E, 337D, 337G, P337H, 337H, 337F… - [TCDS A2CE](https://openairdocs.org/tcds/A2CE): Textron Aviation Inc.; names 1 of 1 models: 336 ## 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: 664 (664 by airframe model, 0 by engine model) - Makers: Cessna 663, Cessna Conroy 1 Models with the most aircraft: - [Cessna T337G](https://openairdocs.org/model/cessna-t337g): 118 aircraft (airframe model) - [Cessna 337G](https://openairdocs.org/model/cessna-337g): 96 aircraft (airframe model) - [Cessna 337A](https://openairdocs.org/model/cessna-337a): 55 aircraft (airframe model) - [Cessna 337](https://openairdocs.org/model/cessna-337): 50 aircraft (airframe model) - [Cessna 337D](https://openairdocs.org/model/cessna-337d): 42 aircraft (airframe model) - [Cessna 337B](https://openairdocs.org/model/cessna-337b): 40 aircraft (airframe model) - [Cessna 336](https://openairdocs.org/model/cessna-336): 35 aircraft (airframe model) - [Cessna M337B](https://openairdocs.org/model/cessna-m337b): 34 aircraft (airframe model) - [Cessna 337C](https://openairdocs.org/model/cessna-337c): 33 aircraft (airframe model) - [Cessna P337H](https://openairdocs.org/model/cessna-p337h): 31 aircraft (airframe model) - [Cessna 337F](https://openairdocs.org/model/cessna-337f): 24 aircraft (airframe model) - [Cessna T337H](https://openairdocs.org/model/cessna-t337h): 23 aircraft (airframe model) - [Cessna 337E](https://openairdocs.org/model/cessna-337e): 21 aircraft (airframe model) - [Cessna T337B](https://openairdocs.org/model/cessna-t337b): 19 aircraft (airframe model) - [Cessna T337C](https://openairdocs.org/model/cessna-t337c): 15 aircraft (airframe model) - [Cessna 337H](https://openairdocs.org/model/cessna-337h): 9 aircraft (airframe model) - [Cessna T337D](https://openairdocs.org/model/cessna-t337d): 7 aircraft (airframe model) - [Cessna T337E](https://openairdocs.org/model/cessna-t337e): 6 aircraft (airframe model) - [Cessna T337F](https://openairdocs.org/model/cessna-t337f): 5 aircraft (airframe model) - [Cessna Conroy 337A](https://openairdocs.org/model/cessna-conroy-337a): 1 aircraft (airframe model) All 20 models: https://openairdocs.org/ad/78-09-05/models.md Every aircraft: https://openairdocs.org/ad/78-09-05/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.