BigGiraffe
Topic Author
Posts: 256
Joined: Sat Jan 29, 2000 7:58 am

Integral Fuel Tanks

Wed Mar 29, 2000 12:08 pm

Wings are sealed during aircraft assembly to hold fuel, since they serve as fuel tanks. This sealant has to be repaired throughout the life of the aircraft as leaks develop or repairs are made to the wing. Does there come a time when this sealant has to be completely stripped out of the wing and new material applied, or does "repair as needed" work until the aircraft is retired?
 
Buzz
Posts: 694
Joined: Sun Nov 21, 1999 11:44 pm

RE: Integral Fuel Tanks, Part 2

Wed Mar 29, 2000 1:18 pm

Hi BigGirrafe, Buzz here. The sealant is pretty much good for the life of the aircraft. Once in a while a tank develops a dribble, and it gets re-gooped in likely places.
We (at UAL) don't plunge into fuel tanks on the line, a few years ago somebody did a stupid accident and asphixiated himself. They had to ignore 3 different rules to do it.
g'nite
Buzz Fuselsausage, Line Mechanic by night, DC-3 crew chief by choice.
 
NKP S2
Posts: 1665
Joined: Mon Dec 20, 1999 3:16 am

RE: Integral Fuel Tanks, Part 2

Wed Mar 29, 2000 1:46 pm

It's just like 'Buzz' said,except that tank entries are done on the line as well as heavy where I work. A negative pressure check is used to detect leaks from the inside,and the same sealant is used to repair any leaks. It's a strong and yet pliable compound. BTW,we were told that fatality was due to the mech using nitrogen to operate an air tool. The nitrogen displaced the O2 in the air in the tank and aphyxiated him. Tanks are suction ventilated for entry and the oxygen level is continually monitored by a work partner that never leaves the area and communicates with the guy in the tank. Forced air respirators are worn if the air quality warrants it. Rules to live by. Literally.
 
dnalor
Posts: 346
Joined: Fri Mar 10, 2000 7:58 pm

RE: Integral Fuel Tanks

Wed Mar 29, 2000 2:20 pm

Where are the access hatches and how big are they?

And the sealant used, is it compatiable with diesel and pertol?

Thankyou
 
NKP S2
Posts: 1665
Joined: Mon Dec 20, 1999 3:16 am

RE: Integral Fuel Tanks

Wed Mar 29, 2000 2:39 pm

There is a series of access panels under the wing pretty much the length of the span,the size and shape of an oval dinner plate. It would suffice to say that the corpulent would have a hard time entering. Getting in is only half the fun,as you must remove internal baffles and navigate the labrynth like interior. A 757 size A/C and up is not too bad,but anything smaller is quite a test of litheness,avoiding damaging wiring,pipes,probes as you slither through...it's no job for the claustrophobic. The sealant used is a type of PRC,chemically cured,that is specific to the job it's done. (we don't use PRC for windshield aerodynamic sealing in the tank). It's a two part mix. Center tanks,where applicable,are generally more "roomy",but are still a PIA to enter. Entrance is generally through an airconditioning pack bay (after removing copious ducting),or through a removeble wall from the wing tanks. On some A/C,the center tank actually resides in the inboard sections of the wing as well as the fuselage. I hope this answers your questions. Later!
 
dnalor
Posts: 346
Joined: Fri Mar 10, 2000 7:58 pm

RE: Integral Fuel Tanks

Wed Mar 29, 2000 3:15 pm

Thanks for answering so promptly.

And I thought working on heavy transport vehicles is bad.
 
Panman
Posts: 603
Joined: Mon Aug 09, 1999 8:25 pm

RE: Integral Fuel Tanks

Wed Mar 29, 2000 6:23 pm

All I can say is I'm glad I am tall with bad knees, I can use this as an excuse to avoid fuel tank duty. Thing is they my put me on toilet tank duty instead!!

Panman
 
BigGiraffe
Topic Author
Posts: 256
Joined: Sat Jan 29, 2000 7:58 am

RE: Integral Fuel Tanks

Thu Mar 30, 2000 12:14 pm

Do you find that you have more problems with leaks as the aircraft passes 20 years old?
 
NKP S2
Posts: 1665
Joined: Mon Dec 20, 1999 3:16 am

RE: Integral Fuel Tanks

Thu Mar 30, 2000 2:20 pm

In a word,no. In my experience,their doesn't seem to be any correlation between age and leaks.

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos