AC 21-17 

DATE 3/15/82 

CIRCULAR 

DEPARTIUEST OF TRASSPORTATIOS 

Federal Aviation Administration 

Washington? D.C. 

FARGUIDANCE MATERIAL 

CARRIAGE OF CARGO IN RESTRICTED CATEZORY AIRCRAFT AN2 OTHEB 

Swbjpct: SPECIAL PURPOSE OPERATIOKS 

1 PURPOSE. This advisory circular (AC) is to advise that the carriage of 

c&go in a restricted category aircraft is amsidered a restricted category 

special purpose operationand provides procedures for designating other special 

purpose operations under Federal Aviation F&gulation (FAR) 21,25(b)(7). 

2 INFOMTION. Types of restricted category special purpose operations are 

listed in FAR 21.25, which also provides in FAR 21,25(b)(7) for other special 

purpose operations as specified by the FAA Administrator. The carriage of 

cargo in restricted catwory aircraft has been authorized cm a case by case 

basis in the past. Howeber, the procedures related to issuance of the type 

certificates and ainmrthiness certificates for that prpose have never been 

published in the AC system. By this AC, therefore, carriage of cargo is 

specified as a special purpose operation under FAR 21,25(b)(7). This AC also 

provides guidance for issuance of type and airworthiness certificates for that 

pumse, and any other special purpose proposed by an applicant. 

3 0 GEINERAL. 

a. A person who applies for a restricted category type ertificate for 

any special purpose operation should be aware that the operating limitations 

imposed on restricted category aircraft by FAR 91.39, among other things, 

prohibit the carriage of persons or property for mqensation m hire, and 

restrict the areas and airports where restricted category aircraft may k 

operated. It should be recognized, therefore, that the strict limitations 

inposed on restricted category aircraft severely limit their practical usage, 

especially for the special purpose of carrying cargo. 

b. The only operations falling within the restricted special prrpse 

category are those items specifically listed in FAR Z&25(b)(l) through (6), 

plus further categories established under (b)(7) after public notice and 

cmnent procedures. Proposals for establishing new special purpose operations 

under FAR 21.25(b)(7) should be submitted to the FAA, 800 Independence Avenue, 

S.W., Washington, D. C. 20591, Attention: Aircraft Manufacturing Division, 

AWS-200, and should include information, views and arguments to substantiate 

Initiated by: AWS-200 
AC 21-17 3/15/82 

that permitting the proposed operation would be in the wblic interest and 

safety wxld not be compromised. The proposal will be published in the Federal 

Register and final actior2 will be taken after evaluation of amments received. 

4 l PROCEDURE. 

a. 7Jpe Certification. A restricted category type certificate is a 

prerequisite to issuance of a restricted ainkhiness certificate for a~ 

individual aircraft l Application for a type mrtificate should be made on 

FAA Fbm 8110-2, APPLICATI~ F'OR TYPE CEFCIFICATE, P~DUCI'ION CERTIFICATE, 

OR SUPPLEMENTAL TWX CEFCIFICATE, and submitted to the Enqineering Division 

or Branch in the FAA Regional Office of the region in which the applicant 

is located. 

(I) lLtl aircraft previously type certificated in one of the standard 

categories may k type certificated in the restricted cateqory under 

FAR 21,25(a)(l), even though the applicant% aircraft may meet all of the 

requirements for a type certificate in another category, and no mdifications 

to the aircraft are needed to acmlish the special purpose. When 

modifications to the aircraft are required for the special purpose, the 

certification basis for approval of the difications muld be the CAR/FAR 

applicable to the original type certification of the aircraft, except that 

the FAA certificating office may waive such of the basic airworthiness 

requirements as may be considered inappropriate for the special purpose. The 

decision to waive any of the basic airxxthiness requirements is to be judged 

on the basis that operation of the aircraft under the waivers and under the 

limitations of FAR 91.39, plus any other operating limitations the type 

certificating office deems appropriate, will not adversely affect public safety. 

(2) The type ertification process for surplus aircraft of the U.S. 

Armed Forces under FAR 21.25(a)(2) would include an FAA evaluation of the 

military safety record of the aircraft model. An aircraft that has been 

declared unairwxthy by the military is not eligible for certification in any 

category. Tne certification basis for approval of tiifications to a military 

surplus aircraft that was never type certificated in any category muld be the 

FAR applicable to the size of the aircraft (i.e., FAR 23 or FAR 25) and a 

showing by the applicant in accordance with FAR 21.25(a) that no feature or 

characteristics of the aircraft makes it unsafe when it is operated under the 

limitations prescribed for its intended use. 

(3) The FAA certificating office may also consider the hazardous 

materials regulations in 49 CFR, Part 175, and in particular Section 175.320 

"Cargo-only Aircraft; only means of transporrtation" when processing an 

application for the special purpose of carriage of cargo. If the applicant 

cannot specify that he will not be carrying hazardous materials in his cargo 

operations, or the applicability of Part 175 with respect to tiifications-that 

may be required is not evaluated during the type oertification pmcess, the 

certificating office wxld include the following limitation in the type 

certificate: "Carriage of hazardous materials is prohibited unless &pliance 

is shown with applicable regulations in @de of Federal Regulations Title 49, 

Part 175. 

2 Par 3 
3/15/Q AC 21-12 

b. Aimrthiness Certification. 

certificate for an aircraft that has 

category is made on FAA F&m 8130-6, - _ 

An application for an airworthiness 

been type certificated in the restrictel3 

APPLICATION FUR AIKWmINESS CERTIFICATE, 

which may be submitted to any l?AA field office. In processing an application 

for a restricted aizlrorthiness certificate for the special purpose of carriage 

of cargo, the FAA certificating inspector will place emphasis in the following 

areas: 

(1) An aircraft issued a restricted category type certificate under 

FAR 21.25(a)(l) must conform to the type design approved under the category for 

which the aircraft was previously certificated, and to the type design for the 

restricted category modifications made to the aircraft. If no tiifications 

had been made to the aircraft, and the aircraft was previously mrtificated in 

the standard category, it must be shown by the applicant to be in condition for 

safe operation and to anform to the type design for the standard category, 

unless the restricted category type design data specifies those airworthiness 

requirements that have been found inappropriate for the special purpose. 

(2) For a surplus military aircraft, FAR 21.185(b) requires the FAA to 

make a finding that the aircraft is in a g& state of preservation and repair 

and in condition ,for safe operation. In making this finding, the certificating 

inspector will require any degree of tear-down far inspection, or search of 

aircraft records that is found necessary to establish the condition of the 

aircraft and the aircraft systems that are subject to deterioration over a long 

period of storage. The inspection of the aircraft may be accomplished in 

conjunct ion with the type certification process. 

(3) In the case of an aircraft that was previously type certificated in 

the standard category, and is to be returned to the standard category after 

operation in the restricted category, the certificating inspector will ensure 

that appropriate inspection requirements are included in the instructions for 

conversion of the aircraft back to standard configuration. !Ihe nature of 

cargo that may have been carried, the areas where the operations had been 

conducted, the surface conditions of the airports that had L>een used, 

and whether the aircraft had been operated at weights over those approved for 

the standard category would all be factors to mnsider in developing an 

inspection prmram that muld determine whether%tructural damage or damage due 

to corrosion caused by the kind of cargo carried or areas of aperation had 

occurred 0 Engineering assistance may be required and requested if Med 

necessary by the certificating inspector. 

(4) A restricted category aircraft may not be operated over any foreign 

country without the special permission of that muntry, since such aircraft may 

not meet the Xntemational Civil Aviation Organization Aimrthiness Cbde, 

Annex 8. Tb ensure that foreign civil air authorities are aware of the status 

of restricted category aircraft exported to their countries, the following note 

will be placed under "exceptions" on all Export Certificates of Aimrthiness, 

FAA Fbrm 8130-4, issue&i for restricted category aircraft: “This Aircraft is 

type certificated in the restricted category and may not meet the applicable 

aimrthiness CDde as provided by Annex 8 to the Convention on International 

Civil Aviation,” 

Par 4 
AC 21-17 3/15/e2 

c. Operations. The operating limitations in FAR 91,39(d) may be waived 

following evaluation of the proposed operations by the FAA. Application for a 

waiver is made on FAA Fbrm 7711-2, APPLICATION FOR CERTIFICATE OF WUVER OR 

AUIMORIZATICX, which may be submitted to the FAA r-ion having jurisdiction 

over the area in which the applicant plans to and&t the operations requiring 

a waiver. Each application for a waiver will be evaluated and processed on an 

individual basis by the appropriate FAA office, to determine *ether: 

(1) the operation with the additional flexibility permitted by the 

waiver and addition21 @eratins limitations applied (if any) will afford an 

equivalent degree of public safety to that resulting from the operation of 

standard category aircraft; and, 

(2) based on individual circumstances, appropriate operating 

limitations and a specific date of expiration for the waiver ansistent with 

completidn of the special purpose operation should be prescribed. 

d Maintenance. Restricted category aircraft are rrot excluded from 

meeti;g any applicable maintenance requirements of FAR Parts 43 and 91, 

including the accomplishment of Aimrthiness Directives. The FAA region in 

which a restricted category aircraft is being operated will take appropriate 

administrative or legal enforcement action whenever a deviation from these 

requirements is discovered. 

e. Ainmrthiness Certificates. ?he FAA region in which restricted 

category aircraft are being operated has authority, under FAR 13.19, in the s 4 

interest of safety and the public interest, to amend ainmrthiness certificates 

as a result of reinspection or investigation of individual circumstances 

related to restricted category operations. 

M. C.Beard 

Director of Airworthiness