sealant test 1, 10025

41問 • 2年前

問題一覧

name 3 areas where sealant is required?

•environmental “prevent entry of fluids, body fairings” •corrosion areas “lavatories/ galleys” •aerodynamic areas •electrical areas “between floor boards above avionics bay”

what is an injection seal?

this is applied to fill channels and voids in the structure that require sealant.

what is a fillet seal?

this is applied along the edges of the structural joints and further protects against fluid and air pressure leaks

what is a fay seal?

this is applied between 2 mating surfaces to prevent corrosion and to keep fluids or air pressure from passing through the joint

what is a prepack seal?

this is applied to holes and voids in structure before assembly where it is not possible to do so afterwards

what is class A sealant?

•low viscosity •applied by brush •applied to fasteners

class B sealant?

•does not sag or run on vertical surfaces •applied by semco gun or spatula •injection, fillet, fay

class C sealant?

•used when long squeeze out life is required •intermediate viscosity sealant •Fay surfaces •brushing or rolling on surfaces

class D sealant

•similar to class B sealant “low slump properties” •extra heavy for hole filling

class E sealant

•Sprayable as a coating •low viscosity sealant •done by manufacturer

class F sealant

•Sprayable as a primer •low viscosity sealant

what class of sealants can be sprayed on?

•class E •class F

what is cure time?

time In hours after mixing required for sealant to cure. “working time” = how long it takes to cure

common areas on aircraft that may have pressurized leaks?

•cargo doors •passenger doors •windows •lap seams •defective fueselage water drain valves

2 common pressure checks?

•positive pressure check “soapy water test” •negative pressure check “vacuum system”

what manuals contain info regarding sealing instructions?

AMM, SRM, SOPM

AC 123 A -2 “AC” meaning ?

manufacturer origin

AC 123 A-2 “123” meaning?

family type applications

AC 123 A-2 “A” meaning

class

AC 123 A -2 “2” meaning?

application time / working time

AC 123 A-2 working time?

2 hours

AC 123 A-1

1 hour

AC 123-1/6 working time?

10 minutes

AC 123 A-1/2 working time?

30 minutes

what is the most common seal on an aircraft?

class B

for a positive pressure check, how much PSI for a good seal?

2-4 psi

what are sealants used for on an aircraft?

•contains fuel •maintains cabin pressure •reduces fire hazards •exlcude moisture •prevents corrosion •fills gap

why are sealants nessesary on float planes?

keeps floats from sinking and prevents corrosion

sealant is required where?

wherever skin is joined to frames, stringers, longerons, etc. maintains pressure and prevents corrosion.

what kind of seal is this?

fillet seal

how to fill a hole while sealing

1. push sealant into hole on pressure side 2. make sealant into smooth fillet on adjacent surfaces 3. for large holes use masking tape for temporary bottom

what types of masking material are used?

masking tape, plastic sheets, wax paper

what are plastic sheets used for?

used where large areas need to be masked for painting

what is wax paper used for?

used when wet sealant needs to be covered temporarily

does class B2 sealant indicate minimum application time or maximum application time?

minimum

squeeze out life?

time in hours after mixing during which a faying surface sealant can be squeezed out of a joint when fasteners are installed

tack free time?

time in hours after mixing that is required for the sealant to cure sufficiently so that it will not transfer to the finger or to a plastic film

what is cure time affected by?

temperature and humidity

does cure time increase or decrease when temperature and humidity is increased ?

cure time will be shortened, decrease

what is a semkit?

complete pre-measured package assembly. easy to mix manually or with machine

can sealant guns be pnematic or manual only?

both Pnematic and manual

Composites test 2

Zachary Halycz · 54問 · 2年前

Composites test 2