AC NO: 21-4B DATE: 7/30/69 ADVISORY CIRCULAR DEPARTMENT OF TRANSPORTATION FEDERAL AVIATION ADMINISTRATION SUBJECT: SPECIAL FLIGHT PERMITS FOR OPERATION OF OVERWEIGHT AIRCRAFT 1. PURPOSE. This circular provides information and guidance with respect to application for, and issuance of special flight permits to operate an aircraft in excess of its maximum certificated takeoff weight, for flight beyond the normal range over water, or over land areas where adequate landing facilities or appropriate fuel is not available. 2. CANCELLATION. AC No. 21-4At effective 9/16/66, is cancelled. 3 • REFERENCE. a. Federal Aviation Regulations (FAR) Part 21, Sections 21.197(b) and 21.199. b. International Flight Info~mation Manual. (This Federal Aviation Administration manual is for sale by the Superintendent of Documents, u. s. Government Printing Office, Washington, D. C. 20402.; 4. GENERAL. FAR 21.197(b) limits the excess weight that may be authorized for overweight operations to additional fuel, fuel carrying facilities, and navigational equipment necessary for the flight. Guidance and information specifically applicable to the applicant's proposed flight may be obtained from any Federal Aviation Administration District or Area Office. The following paragraphs provide general information which should be helpful to the applicant. a. Application for a special flight permit is made on FAA Form 8130-6 "Application for Airworthiness Certificate." (A sample form is in Appendix 1). FAR 21.199 establishes the general application requirements. Initiated by: FS-180 Page 2 AC 21-4B 7/30/69 b. FAR Part 43 prescribes requirements for approval, return to service, and alteration records associated with the installation of additional facilities. Appendix. B of FAR Part 43 and Advisory Circular 43.9-lB give instructions for completion of the FM Form 337, on which alter­ ations are recorded. c. lt is recommended th'at the applicant discuss the proposed flight with the manufacturer of the aircraft or an FAA-approved repair station, to determine the availability of technical data on the installation of additional fuel carrying facilities and/or navigational equipment. d. Before flight to a foreign country of an aircraft having a special flight permit authorizing overweight operation, the applicant should determine whether operating requirements may be imposed by that country, and any other country on the route of flight, because of the condition of the aircraft. (See Section Don the reverse side of the Special Airworthiness Certificate, FAA Form 8130-7.) A request for permission to operate over or within a foreign country should include a statement describing the deviations from the FAA airworthiness standards. (Such deviations, in effect, would also be deviations from the airworthiness standards of Annex 8 to the Convention on International Civil Aviation (ICAO), since the FAA standards meet !CAO requirements.) With respect to an aircraft operating under FAR 21.197 (b), the statement may be worded as follows: 11 This air~ craft does not comply with the International Airworthiness Standards of Annex 8 to the Convention on International Civil Aviation when operated at a weight in excess of its maximum certificated takeoff weight because of the addicional fuel, fuel carrying facilities, and navigation equipment installed in the aircraft. 11 (Note: The words 11and navigation equipment" should not be used if such additional equipment is not required for the flight.) e. If the aircraft is being exported1 the applicant must comply with any applicable requirements established by the Departments of State, Treasury. and Commerce, and, if an FAA Export Certificate of Airworthiness is required, with the applicable regulations in FAR Part 21, Subpart L. The FAA International Flight Information Manual also provides guidance with respect to the requirements for navigation and operation of aircraft in foreign countries, as well as other miscellaneous information of value to persons contemplating flights outside of the United States. 5. CRITERIA USED TO DETERMINE THE SAFETY OF ADDITIONAL FACILITIES. In approving the installation of additional facilities, the FAA DUst find that the altered aircraft is safe for operation. To assist in arriving at such a determination, the following questions are normally considered: Par. 4 AC 21-4B Page 3 7/30/69 a. Does the technical data include installation drawings, structural substantiating reports, weight, balance, new center of gravity limits computations, and aircraft performance limitations in sufficient detail to allow a conformity inspection of the aircraft to be made? b. In what ways does the aircraft not comply with the applicable air­ worthiness requirements (See FAR 21.199(a)(4))? c. Are the fuel tanks vented to the outside? Are all areas in which tanks are located ventilated to reduce fire, explosion, and toxicity hazards? d. Are the tanks even when empty strong enough to withstand the differ­ ential pressure at maximum operating altitude for a pressurized aircraft? e. Have means been provided for determining the fuel quantity in each tank p~ior to flight? f. Are shutoff valves, accessible to the pilot, provided for each .additional tank to disconnect these tanks from the main fuel system? g. Are the additional fuel tank filler connections designed to prevent spillage within the aircraft during servicing? h. Is the engine oil supply and cooling adequate for the extended weight and range? 6. LI~UTATIONS. The following types of limitations may be necessary for safe operation of the aircraft (Reference FAR 21.199(a)(6)): a, Revised operational airspeeds for use in the overweight condition~ b, Increased pilot skill requirements. c. A prescribed sequence for using fuel from various tanks as necessary to keep the aircraft within its center of gravity range. d. Notification to the control tower of the overweight takeoff condition to permit use of a runway to minimize flight over congested areas. e. Avoidance of severe turbulence. If encountered, the aircraft should be inspected for damage as soon as possible. Par, 5 Page 4 AC 21-4B 7/30/69 £. Notification to the nearest District or Area Office located at the point of departure from the u. S. in sufficient time for that office to determine that the aircraft still conforms to the terms and conditions of the special flight permit. ,.%"- Director --:::, Flight Standards Service Par, 6 AC 21-4B Appendix 1 7/30/69 Page 1 Example of an Application for a Special Flight Permit for Operation in Excess of Maxiwum Certificated Takeoff Weight (Face Side) Fo,m Approved Bud~e1 B..ireill ~ No. 04-ROO~S INST:Ht(llONS-Fn~t or r:,pt" uo noc •rn-e 1n shJd~d Ht..U, th.ex 0~1'411,..., fNf 0 1 flA. ,d~~OITA!IOH 1 1 1 fE~ f ""Al A.Vl ,\1i0N A0MIN!STRJITl0N ~;;,~~c,~~:;iv~~c-Jr~ Jdi~i~~~ ~:::tt:1~e;~{,~d. ~~·~~h~t::i:..;~~ 1 Fo, spe-c1.Jl tligh: r ~rm ju complece Sections 11 and VI or V[? ~• Afr\ 0.TION FOR AIRWO~TH!:ms crnTIFICATE ap ;-11o bll" ~ 1 • tc:!! iv.r·c "" ....,..,..: , i ...11u..,, 1-1.nioo s h,l,.Mf r,,,.,,) 1 ..1ai:: 1,1,,H ....c oh cuLc;.M,.,nO N I,._ ,~ "'v. fA.,lt, cocm,10 i;' f-,- .-,.c­. l-•fl=-:Sc,[l·,.--,­.-0---+c,,--,,-N-,­CI-~-:-,,­lu--Ci.CCOC--:!1-CS--N--,.,,.--:-,--,~-,--,,--)---+:,-.7,NC:G:-C,~C:(C'."'"""'.OC:0-:'.fl"""'.CC:!C:,ie:::'.N--~C:f,O=N~---;-----------j .; V ~ ;; 11. A•1cu.n 1s I N!W I ! U!!D I I •""()IT f',11: Pl,l(ATION ! S H~K(!!.'f MAOI FO~:, ;."-·,_-t .,,,.• ·_ ,., ,:, .:, ,.., j ,i. ! I !ST ANO•~D 1'.l~wc ~rn1NbS CE .IT d•J,/tf.~ ,, .,).'ir.; r"J / : ;,...:::~_..,.,,~ I lur ,~1n I I 1.C.1toa... nc l ln,,NSl'OUj ! C(.1Df• I fuuooN ~ 1 'X I s r.r::IAl A.L ;:wc:;:Tt-, ;N~55 Ct !i'TiflCATE. i ( -' .... ,1_fJ_t,~ ~.. n 1/ t :/t•m j I I I t (.,A.l5 I I 2 I l•U:""l !.U•v fYINC[ J I r.~~::W.tN~ Is I 1~•TIOlLINO I 6 I !wHt,lHfl CONlltOl I 2 I l.;,..,,,._.,.TYUll IUIU I J I 10:~1•1~1°"4 f 0:"ftu,,~N'T'AL rJ,.J" , r~ ~;,~J:,;,,./ i) kl£WT(AFNl~G j.....11:, su•vn ' .' o ,., , on.:·,,. ,•tJ / I 5 I i 6 I 51 ii s, ( CIAL fllC,HT 'fDMJT I f 'lit(,l{I ,....,.1-t---;­ :'-"­'-'-"-'G_•_r_,o_,_._.,_._.._,._._,'­'"­"°"-­'-·_~_,N_,_,._._._<_•_o _•_ _0_.._v1_______-t ! I • · .1 · -,1~ , 2 I t -1.o. CUAU a o"' """"' o, IM'1:N0 1,-.c DA.NCH ' 8 I lt~"_'.:7/o;'/;·t,;~.,,.~;r'~;;:,. '---..--+----------­- --------------1 .,.·#u .1, • ­ --------t j 11 1 1----'.J.,.._X,___,_k_,_,._,_:;_o_a_,a_,_,_<•_s_s_o•_=__c_,_.,_.,_•<_•'~'°-''~'-'·_c_,._w_,_,c_"_' I lx 4 I ::O l,: v £;;•>,1G Ot fJ,0'1 I 5 • t'IOOUCTION r1IG,-li l UTING C,6 ' ,y,1,.11,,,,..F-Lf A '·'l'<10 ~:'•·n':'IU5 CU!";: PCA.H · ·: , .~ .: ~/ r'_,"r1.1 '! R1;: r.•.t1. I 1J;,,-r.lf; Jr1 ...i-r.i il-·11./...r.i ~r l_1 >r1:11J ..11 .,_,".~l:: Jl//1 .1!-urr) 1--r-,­,-,c-,';,----,-,,--O­O-WNS• ( ,, ,:.. ,.. ,., ,,·.··:'"'" -· h .u :J ~,.; ·,:,.. ,,.,,; IF DEALE.~. CHECK HE~E -- j ~ C A1 1i:O:An o;,u:...r:or~ J.NO MAINTfNANCI: ~'!:CO RDS e r-Tc-.trr:. _J .:f i:: :.;:~ ... ·1 TO TAL J. ,~,u..... r k CUIS-EOJ.'tr / .r IIJtd ,:r-:,4,• ,.,.,, :Z I cc... ~,1.... t,1 ( f wm; 3 l~Al ~ l 1 rl 0 c. cu11,1(A710t~ - I h<:rct .• ;r-r:d:, t r',J~ I .1m 1h r: 0 11 ner (o, h i1 .1g~r:c~ c(ihr­ 11r ~:.i.(1 JC"swbd Jbo\·-c; th~t the 1ttcr1ft i~ :~s:isrered .,.;d, the ;:C" ~r: ul A, ,.i11.::i :, .'\1!-r.