Forum: General F-16 forum

Hi,

F-16 fuel internal vent and pressurization system has two types of schedule. The normal schedule, [Link pending approval] psig, and the combat schedule, 1-3psig or [Link pending approval] whichever is greater.

I just want to know why do we need to switch from normal schedule to combat schedule during Tank Inerting and Aerial Refueling.

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At air refueling it simply increses the flow, saving time. At combat / inerting mode,- you might find your answer here.

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA351434

gumme wrote:

At air refueling it simply increses the flow, saving time. At combat / inerting mode,- you might find your answer here.

[Link pending approval]

the reason for lowering air pressure during air refueling is the external wing tanks are pressurized to 19 to 24 psi for normal transfer, if they do not drop to 0psig they will not receive fuel during air refuel. (there are no pumps in the 370gl and 300gl tanks)
the reason the internal fuel tanks drop pressure during air refueling is the air has to escape from the tanks to make room for the fuel.
and during tank inerting they need the air (fumes) to leave the aircraft so the halon can replace it.
this is best was i could think to explain it and keep it simple.

When IFR door is opened the tanks vent?

THANKS EVERYONE FOR THE INFORMATION. IN ADDITION TO MY QUESTION, I AM CURIOUS IF THE SWITCHING OVER OF NORMAL TO COMBAT SCHEDULE DOES HAVE ANY RELATION WITH PROTECTING THE STRUCTURE OF THE AIRCRAFT SINCE IT MAY EXPERIENCE VERY DRASTIC MANEUVERS DURING TANK INERT.

gumme I WILL TAKE SOME TIME TO LOOK AT THE ARTICLE. THANKS.

VarkVet, IF YOU ARE REFERING TO THE IN FLIGHT REFUEL DOOR, WHEN THE DOOR OPENED, THE EXTERNAL TANKS WILL DEPRESSURISE AND INTERNAL TANK WILL GO INTO COMBAT MODE. AND YES, THE TANKS WILL VENT THE EXCESS PRESSURE BY THE INTERNAL AND EXTERNAL VENT AND PRESSURIZATION VALVES THROUGH THE VENT PORT.

f16-student wrote:

I AM CURIOUS IF THE SWITCHING OVER OF NORMAL TO COMBAT SCHEDULE DOES HAVE ANY RELATION WITH PROTECTING THE STRUCTURE OF THE AIRCRAFT SINCE IT MAY EXPERIENCE VERY DRASTIC MANEUVERS DURING TANK INERT.

No relation since the maneuvers flown in training without tank inerting are like the maneuvers that could be flown in combat with tank inerting.

exfltsafety, THANKS. =)

Forum: General F-16 forum

Fuel internal vent and pressurization