DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

Subject:  INSTRUCTIONS FOR COMPLETION OF FAA FORM 337 (OMB NO. 2120-0020), MAJOR REPAIR AND ALTERATION (AIRFRAME POWERPLANT, PROPELLER, OR APPLIANCE)

Date: 5/21/87

Advisory Circular No: 43.9-1E

Initiated by: AFS-340

Change:

1.  PURPOSE. This advisory circular (AC) provides instructions for completing Federal Aviation Administration (FAA) Form 337, Major Repair and Alteration (Airframe, Powerplant, Propeller, or Appliance).

2.  CANCELLATION. AC 43.9-1D, instructions for Completion of FAA Form 337 (OMB 04-R0060 Major Repair and Alteration (Airframe, Powerplant, Propeller, or Appliance), dated 9/5/79, is canceled.

3.  RELATED FEDERAL AVIATION REGULATIONS (FAR) SECTIONS.  FAR Part 43, Sections 43.5, 43.7, 43.9, and Appendix B.

4.  INFORMATION. FAA Form 337 is furnished free of charge and is available at all FAA Air Carrier (ACDO), General Aviation (GADO), Manufacturing Inspection (MIDO), and Flight Standards (FSDO) district offices, and at all International Field Offices (IFO).  The form serves two main purposes; one is to provide aircraft owners and operators with a record of major repairs or alterations indicating details and approval, and the other is to provide the FAA with a copy of the form for inclusion in the aircraft records at the FAA Aircraft Registration Branch, Oklahoma City, Oklahoma. 

5.  INSTRUCTIONS FUR COMPLETING FAA FORM 337.  The person who performs or supervises a major 'repair or major alteration should prepare FAA Form 337.  The form is executed at least in duplicate and is used to record major repairs and major alterations made to an aircraft, an airframe, powerplant, propeller, appliance, or spare part.  The following instructions apply to corresponding items 1 through 8 of the form as illustrated in Appendix 1. 

   a.	Item 1 - Aircraft.  Information to complete the "Make," "Model," and "Serial Number" blocks will be found on the aircraft manufacturer's identification plate.  The "Nationality and Registration Mark" is the same as shown on AC Form 8050-3, Certificate of Aircraft Registration. 

   b.	Item 2 - Owner.  Enter the aircraft owner's complete name and address as shown on AC Form 8050-3.

   Note:	When a major repair or alteration is made to a spare part or appliance, items 1 and 2 will be left blank, and the original and duplicate copy of the form will remain with the part until such time as it is installed on an aircraft.  The person installing the part will then enter the required information in blocks 1 and 2, give the original of the form to the aircraft owner/operator, and forward the duplicate copy to the local FAA district office within 48 hours after the work is inspected.

   c.	Item 3 - For FAA Use Only.  Approval may be indicated in Item 3 when the FAA determines that data to be used in performing a major alteration or a major repair Complies with accepted industry practices and all applicable FAR.  Approval is indicated in one of the following methods. (See paragraph 6b for further details.) 

	(1)	Approval by examination of data only - one aircraft only: "The data identified herein complies with the applicable airworthiness requirements and is approved for the above described aircraft, subject to conformity inspection by a person authorized in FAR Part 43, Section 43.7."

	(2)	Approval by physical inspection, demonstration, testing, etc., of the data an aircraft - one aircraft only: "The alteration (or repair) identified herein complies with the applicable airworthiness requirements and is approved for the above described aircraft, subject to conformity inspection by a person authorized in FAR Part 43, Section 43.7."

	(3)	Approval by examination of data only - duplication on identical aircraft.  "The alteration identified herein complies with the applicable airworthiness requirements and is approved for duplication on identical aircraft make, model, and altered configuration by the original modifier."

   d.	4 - Unit Identification.  The information blocks under item 4 are used to identify the airframe, powerplant, propeller, or appliance repaired or altered.  It is only necessary to complete the blocks for the unit repaired or altered.

   e.	Item 5 - Type.  Enter a checkmark in the appropriate column to indicate if the unit was repaired or altered. 

   f.	Item 6 - Conformity Statement.

	(1)	"A" - Agency's Name and Address.  Enter name of the mechanic, repair station, or manufacturer accomplishing the repair or alteration.  Mechanics should enter their name and permanent mailing address.  Manufacturers and repair stations should enter the name and address under which they do business.

	(2)	"B" - Kind of Agency.  Check the appropriate box to indicate the type of person or organization who performed the work. 

	(3)	"C" - Certificate Number.  Mechanics should enter their mechanic certificate number in t is block, e.g., 1305888.  Repair stations should enter their air agency certificate number and the rating or ratings under which the work was performed, e.g., 1234, Airframe Class 3. Manufacturers should enter their type production or Supplemental Type Certificate (STC) number.  Manufacturers of Technical Standard Orders (TSO) appliances altering these appliances should enter the TSO number of the appliance altered. 

	(4)	"D" - Compliance Statement: This space is used to certify that the repair or alteration was made in accordance with the FAR.  When work was performed or supervised by certificated mechanics not employed by a manufacturer or repair station, they should enter the date the repair or alteration was completed and sign their full name.  Repair stations are permitted to authorize persons in their employ to date and sign this conformity statement.

   g.	Item 7 - Approval for Return to Service.  FAR Part 43 establishes the conditions under which major repairs or alterations to airframes, powerplants, propellers, and/or appliances may be approved for return to service.  This portion of the form is used to indicate approval or rejection of the repair or alteration of the unit involved and to identify the person or agency making the airworthiness inspection.  Check the "approved" or "rejected" box to indicate the finding.  Additionally, check the appropriate box to indicate who made the finding.  Use the box labeled "other" to indicate a finding by a person other than those listed.  Enter the date the finding was made.  The authorized person who made the finding should sign the form and enter the appropriate certificate or designation number. 

   h.	Item 8 - Description of Work Accomplished.  A clear, concise, and legible statement describing the work accomplished should be entered in item 8 on the reverse side of FAA Form 337.  It is important that the location of the repair or alteration, relative to the aircraft or component, be described.  The approved data used as the basis for approving the major repair or alteration for return to service should be identified and described in this area. 

	(1)	For example, if a repair was made to a buckled spar, the description entered in this part might begin by stating, "Removed wing from aircraft and removed skin from outer 6 feet.  Repaired buckled spar 49 inches from tip in accordance with . . . ." and continue with a description of the repair.  The description should refer to applicable FAR sections and to the FAA-approved data used to substantiate the airworthiness of the repair or alteration.  If the repair or alteration is subject to being covered by skin or other structure, a statement should be made certifying that a precover inspection was made and that covered areas were found satisfactory. 

	(2)	Data used as a basis for approving major repairs or alterations for return to service must be FAA-approved prior to its use for that purpose and includes: FAR (e.g., airworthiness directives), AC's (e.g., AC 43.13-1A under certain circumstances), TSO's parts manufacturing approval (PM), FAA-approved manufacturer's instructions, kits and service handbooks, type certificate data sheets, and aircraft specifications.  Other forms of approved data would be those approved by a designated engineering representative (DER), a manufacturer holding a delegation option authorization (DOA), STC'S, and, with certain limitations, previous FAA field approvals.  Supporting data such as stress analyses, test reports, sketches, or photographs should be submitted with the FAA Form 337.  These supporting data will be returned to the applicant by the local FAA district office since only FAA Form 337 is retained as a part of the aircraft records at Oklahoma City. 

	(3)	If additional space is needed to describe the repair or alteration, attach sheets bearing the aircraft nationality and registration mark and the date work was completed. 

	(4)	Showing weight and balance computations under this item is not required; however, it may be done.  In all cases where weight and balance of the aircraft are affected, the changes should be entered in the aircraft weight and balance records with the date, signature, and reference to the work performed on the FAA Form 337 that required the changes.

6.  ADMINISTRATIVE PROCESSING.  At least an original and one duplicate copy of the FAA Form 337 will be executed.  FAA district office processing of the forms and their supporting data will depend upon whether previously approved or non-previously approved data was used as follows: 

   a.	Previously Approved Data.  The forms will be completed as instructed in this AC ensuring that item 7, "Approval for Return to Service," has been properly executed.  Give the original of the form to the aircraft owner or operator, and send the duplicate copy to the local FAA district office within 48 hours after the work is inspected. 

  b.	Non-previously Approved Data.  The forms will be completed as instructed in this AC, leaving item 7, "Approval for Return to Service," blank.  Both copies of the form, with supporting data, will be sent to the local FAA district office.  When the FAA determines that the ma* .)or repair or alteration data complies with applicable regulations and is in conformity with accepted industry practices, data approval will be recorded by entering an appropriate statement in item 3, "For FAA Use Only." Both forms and supporting data will be returned to the applicant who will complete item 7, "Approval for Return to Service." The applicant will give the original of the form, with its supporting data, to the aircraft owner or operator and return the duplicate copy to the local FAA district office who will, in turn, forward it to the FAA Aircraft Registration Branch, Oklahoma City, Oklahoma, for inclusion in the aircraft records.

   c.	Signatures on FAA Form 337 have limited purposes:

	(1)	A signature in item 3, "For FAA Use Only," indicates approval of the data described in that section for use in accomplishing the work described under item 8 on the reverse of FAA Form 337. 

	(2)	A signature in item 6, "Conformity Statement," is a certification by the person performing the work that it was accomplished in accordance with applicable FAR and FAA-approved data.  The certification is only applicable to that work described under item 8 on the reverse of FAA Form 337.

   Note:		Neither of these signatures (subparagraph c(1) and c(2)) indicate FAA approval of the work described under item 8 for return to service.

	(3)	A signature in item 7, "Approval for Return to Service," does not signify FAA approval unless the box to the left of "FAA Flight Standards inspector" or "FAA Designee" is checked.  The other persons listed in item 7, are authorized to "approve for return to service" if the repair or alteration is accomplished using FAA-approved data, is performed in accordance with applicable FAR, and found to conform. 

   d.	FAA Form 337 is not authorized for use on other than U.S.-registered aircraft'.  If a foreign civil air authority requests the form, as a record of work performed, it may be provided.  The form should be executed in accordance with the FAR and this AC.  The foreign authority should be notified on the form that it is not an official record and that it will not be recorded by the FAA Aircraft Registration Branch, Oklahoma City, Oklahoma. 

   e.	FAR Part 43, Appendix B, Paragraph (b) authorizes FAA certificated repair  stations to use a work order, in lieu of FAA Form 337, for only major repairs.  Such work orders should contain all the information provided on the form and in no less detail; that is, the data used as a basis of approval should be identified, a certification that the work was accomplished using that data and in accordance with the FAR, a description of the work performed (as required in item 8 of the FAA Form 337), and approval for return to service must be indicated by an authorized person.  Signature, kind of certificate, and certificate number must also appear in the record (reference FAR Section 43.9). 

William T. Brennan Acting Director of Flight Standards

NOTE:	APPENDIX 1  FAA FORM 337 OMITTED ON THIS VERSION OF ADVISORY CIRCULAR.

Contact FSDO for copy of form.