FAA AC 25-21:1999
FAA AC 25-21:1999 Certification Of Transport Airplane Structure
Table of Contents
CHAPTER1STRUCTURESection1GENERAL
1Section25.301Loads
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[2-10][RESERVED]
11Section25.303Factorofsafety
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[12-22][RESERVED]
23Section25.305Strengthanddeformation
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[24-34][RESERVED]
35Section25.307Proofofstructure
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[36-44][RESERVED]
Section2FLIGHTLOADS
45Section25.321General
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[46-54][RESERVED]
Section3FLIGHTMANEUVERANDGUSTCONDITIONS
55Section25.331Symmetricmaneuveringconditions
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[56-64][RESERVED]
65Section25.333Flightmaneuveringenvelope
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[66-76][RESERVED]
77Section25.335Designairspeeds
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[78-86][RESERVED]
87Section25.337Limitmaneuveringloadfactors
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[88-96][RESERVED]
97Section25.341Gustandturbulenceloads
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[98-108][RESERVED]
109Section25.343Designfuelandoilloads
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[110-118][RESERVED]
119Section25.345Highliftdevices
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[120-128][RESERVED]
129Section25.349Rollingconditions
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[130-137][RESERVED]
138Section25.351Yawmaneuverconditions
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[139-147][RESERVED]
Section4SUPPLEMENTARYCONDITIONS
148Section25.361Enginetorque
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[149-157][RESERVED]
158Section25.363Sideloadonengineandauxiliary
powerunitmounts
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[159-168][RESERVED]
169Section25.365Pressurizedcompartmentloads
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[170-177][RESERVED]
178Section25.367Unsymmetricalloadsduetoenginefailure
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[179-187][RESERVED]
188Section25.371Gyroscopicloads
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[189-199][RESERVED]
200Section25.373Speedcontroldevices
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[201-208][RESERVED]
Section5CONTROLSURFACEANDSYSTEMLOADS
209Section25.391Controlsurfaceloads:general
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[210-217][RESERVED]
218Section25.393Loadsparalleltohingeline
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[219-227][RESERVED]
228Section25.395Controlsystem
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[229-238][RESERVED]
239Section25.397Controlsystemloads
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[240-249][RESERVED]
250Section25.399Dualcontrolsystem
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[251-259][RESERVED]
260Section25.405Secondarycontrolsystem
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[261-268][RESERVED]
269Section25.407Trimtabeffects
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[270-275][RESERVED]
276Section25.409Tabs
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[277-286][RESERVED]
287Section25.415Groundgustconditions
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[288-297][RESERVED]
298Section25.427Unsymmetricalloads
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[299-307][RESERVED]
308Section25.445Auxiliaryaerodynamicsurfaces
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[209-318][RESERVED]
319Section25.457Wingflaps
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[320-328][RESERVED]
329Section25.459Specialdevices
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[330-339][RESERVED]
Section6GROUNDLOADS
340Section25.471General
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[341-349][RESERVED]
350Section25.473Landingloadconditionsandassumptions
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[351-361][RESERVED]
362Section25.477Landinggeararrangement
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[363-369][RESERVED]
370Section25.479Levellandingconditions
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[371-380][RESERVED]
381Section25.481Taildownlandingconditions
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[382-389][RESERVED]
390Section25.483Onegearlandingconditions
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[391-398][RESERVED]
399Section25.485Sideloadconditions
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[400-409][RESERVED]
410Section25.487Reboundlandingcondition
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[411-420][RESERVED]
421Section25.489Groundhandlingconditions
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[422-434][RESERVED]
435Section25.491Taxi,takeoff,andlandingroll
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[436-446][RESERVED]
447Section25.493Brakedrollconditions
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[448-458][RESERVED]
459Section25.495Turning
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[460-468][RESERVED]
469Section25.497Tail-wheelyawing
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[470-477][RESERVED]
478Section25.499Nose-wheelyawandsteering
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[479-482][RESERVED]
483Section25.503Pivoting
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[484-488][RESERVED]
489Section25.507Reversedbraking
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[490-495][RESERVED]
496Section25.509Towingloads
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[497-508][RESERVED]
509Section25.511Groundload:unsymmetricalloadson
multiple-wheelunits
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[510-519][RESERVED]
520Section25.519Jackingandtie-downprovisions
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[521-528][RESERVED]
Section7WATERLOADS
529Section25.521General
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[530-540][RESERVED]
541Section25.523Designweightsandcenterofgravity
positions
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[542-548][RESERVED]
549Section25.525Applicationofloads
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[550-559][RESERVED]
560Section25.527Hullandmainfloatloadfactors
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[561-568][RESERVED]
569Section25.529Hullandmainfloatlandingconditions
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[570-575][RESERVED]
576Section25.531Hullandmainfloattakeoffcondition
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[577-583][RESERVED]
584Section25.533Hullandmainfloatbottompressures
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[585-589][RESERVED]
590Section25.535Auxiliaryfloatloads
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[591-597][RESERVED]
598Section25.537Seawingloads
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[599-602][RESERVED]
Section8EMERGENCYLANDINGCONDITIONS
603Section25.561General
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[604-610][RESERVED]
611Section25.562Emergencylandingdynamicconditions
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[612-620][RESERVED]
621Section25.563Structuralditchingprovisions
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[622-628][RESERVED]
Section9FATIGUEEVALUATION
629Section25.571Damage-toleranceandfatigueevaluation
ofstructure
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[630-638][RESERVED]
Section10LIGHTNINGPROTECTION
639Section25.581Lightningprotection
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
640-650[RESERVED]
CHAPTER2DESIGNANDCONSTRUCTION
Section1GENERAL
651Section25.601General
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[652-658][RESERVED]
659Section25.603Materials
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[660-668][RESERVED]
669Section25.605Fabricationmethods
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[670-675][RESERVED]
676Section25.607Fasteners
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[677-683][RESERVED]
684Section25.609Protectionofstructure
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[685-692][RESERVED]
693Section25.611Accessibilityprovisions
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[694-698][RESERVED]
699Section25.613Materialstrengthpropertiesand
designvaluesaRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[700-707][RESERVED]
708Section25.615[Removed]
709Section25.619Specialfactors
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[710-718][RESERVED]
719Section25.621Castingfactors
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[720-728][RESERVED]
729Section25.623Bearingfactors
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[730-738][RESERVED]
739Section25.625Fittingfactors
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[740-745][RESERVED]
746Section25.629Aeroelasticstabilityrequirements
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[747-759][RESERVED]
760Section25.631Birdstrikedamage
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[761-769][RESERVED]
Section2CONTROLSURFACES
770Section25.651Proofofstrength
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[771-778][RESERVED]
779Section25.655Installation
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[780-787][RESERVED]
788Section25.657Hinges
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[789-793][RESERVED]
Section3CONTROLSYSTEMS
794Section25.671General
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[795-800][RESERVED]
801Section25.672Stabilityaugmentationandautomatic
andpoweroperatedsystems
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[802-810][RESERVED]
811Section25.673Two-ControlAirplanes-[Removed]
812Section25.675Stops
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[813-818][RESERVED]
819Section25.677Trimsystems
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[820-827][RESERVED]
828Section25.679Controlsystemgustlocks
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[829-835][RESERVED]
836Section25.681Limitloadstatictests
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[837-844][RESERVED]
845Section25.683Operationtests
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[846-851][RESERVED]
852Section25.685Controlsystemdetails
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[853-860][RESERVED]
861Section25.689Cablesystems
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[862-867][RESERVED]
868Section25.693Joints
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[869-875][RESERVED]
876Section25.695Power-boostandpower-operatedcontrol
system-[Removed]
aRuletext
877Section25.697Liftanddragdevices,controls
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[878-886][RESERVED]
887Section25.699Liftanddragdeviceindicator
aRuletext
888Section25.701Flapandslatinterconnection
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[889-896][RESERVED]
Section4LANDINGGEAR
897Section25.721General
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[898-907][RESERVED]
908Section25.723Shockabsorptiontests
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[909-913][RESERVED]
914Section25.725Limitdroptests
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[915-921][RESERVED]
922Section25.727Reserveenergyabsorptiondroptests
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[923-928][RESERVED]
929Section25.729Retractingmechanism
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[930-938][RESERVED]
939Section25.731Wheels
aRuletext
[940-946][RESERVED]
947Section25.733Tires
aRuletext
[948-954][RESERVED]
955Section25.735Brakes
aRuletext
[956-960][RESERVED]
961Section25.737Skis
aRuletext
[962-966][RESERVED]
Section5FLOATSANDHULLS
967Section25.751Mainfloatbuoyancy
aRuletext
[968-973][RESERVED]
974Section25.753Mainfloatdesign
aRuletext
[975-977][RESERVED]
978Section25.755Hulls
aRuletext
[979-981][RESERVED]
Section6PERSONNELANDCARGOACCOMMODATIONS
982Section25.771Pilotcompartment
aRuletext
[983-988][RESERVED]
989Section25.772Pilotcompartmentdoors
aRuletext
[990-996][RESERVED]
997Section25.773Pilotcompartmentview
aRuletext
[998-1003][RESERVED]
1004Section25.775Windshieldsandwindows
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[1005-1015][RESERVED]
1016Section25.777Cockpitcontrols
aRuletext
[1017-1022][RESERVED]
1023Section25.779Motionandeffectofcockpitcontrols
aRuletext
[1024-1029][RESERVED]
1030Section25.781Cockpitcontrolknobshape
aRuletext
[1031-1037][RESERVED]
1038Section25.783Doors
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[1039-1049][RESERVED]
1050Section25.785Seats,berths,safetybelts,andharnesses
aRuletext
[1051-1054][RESERVED]
1055Section25.787Stowagecompartments
aRuletext
[1056-1059][RESERVED]
1060Section25.789Retentionofitemsofmassin
passengerandcrewcompartmentsandgalleys
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[1061-1068][RESERVED]
1069Section25.791Passengerinformationsignsandplacards
aRuletext
[1070-1072][RESERVED]
1073Section25.793Floorsurfaces
aRuletext
[1074-1075][RESERVED]
Section7EMERGENCYPROVISIONS
1076Section25.801Ditching
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[1077-1085][RESERVED]
Section8FIREPROTECTION
1086Section25.865Fireprotectionofflightcontrols,
enginemounts,andotherflightstructure
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[1087-1095][RESERVED]
1096Section25.867Fireprotection:othercomponents
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[1097-1105][RESERVED]
Section9MISCELLANEOUS
1106Section25.871Levelingmeans
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[1107-1112][RESERVED]
Section10FUELSYSTEM
1113Section25.963Fueltanks:general
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[1114-1122][RESERVED]
Section11OPERATINGLIMITATIONS
1123Section25.1517Roughairspeed,VRA
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[1124-1129][RESERVED]
1130Section25.1529
AppendixHInstructionsforcontinuedairworthiness
aRuletext
bIntentofrule
cBackground
dAcceptablecompliancemethods
eReferences
[1131-1140][RESERVED]
APPENDICES
APPENDIX1Glossaryofacronymsandabbreviations
APPENDIX2Indexofincorporatedguidancematerialand
references