Forum: F-16 Procedures

Joined: Feb 01, 2007 - 02:38 AM Posts: 0 Status: Offline

We tag-team ours when required. You can get the bottles back up to pressure real quick if you have 5 or 6 guys in line waiting to pump-like-mad............ Wink

If you have a good JFS maintenance crew taking care of your starters you shouldn't be having to pump too often.

If you have a JFS no-start once, the book says it's ok to pump and try again, but if you have to do that on every sortie, something is wrong and you should be troubleshooting the system. If we have to pump a jet's bottles more than twice in a given week or so, that jet will get a DESSC to watch the system and try to isolate a fault. You have to be pro-active on JFS maintenance if you want a good start rate. Ignore the system, and you're pumping bottles every launch of every day.

As for JFS no-starts on either engine type, the JFS system is the same. What difference would it make to the JFS? I think it would boil down to the maintenance at the base/unit you're with, more than the engine type.

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As for JFS no-starts on either engine type, the JFS system is the same. What difference would it make to the JFS? I think it would boil down to the maintenance at the base/unit you're with, more than the engine type.

I agree, I have worked both GE and PW. For engine maintenance I prefer the GE. But the JFS system doesn't give a rat's toe nail what engine is in the jet, other than shut down. on a PW it shuts down at 50 percent. On a ge I believe it's 54 percent. However it's been a few years since I have run a GE engine.

You are right crewdawg on the GE it shuts down at 54 percent.

Rigo

Hey Guys this is helping me study for my block test. I am in block 7 now but never really understood the JFS but I believe I do now.

362 Crew Dawgs

New Crew Chief, if you have any questions about your study material your not grasping, let me or any of the other crew chiefs here know, and we can help simplify it for you.

Well said CrewDawg,The more knowledgeable Crew Chiefs or willing to learn Crew Chiefs we have coming up the better it is for all of us.

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In the bottom of the engine bay of the F-16 are 2 long skinny yellow tubes called the JFS / brake accumulators. These bottles are pressurized to 3000 PSI each. The pilot selects battery power in the cockpit, then he selects JFS start 1 (which blows 1 bottle) or JFS start 2 (both bottles).

Actually the Jet has to be started in MAIN PWR and usaully only start 2 is selected. Start 1 is used for trouble shooting No Start Problems or JFS Problems. Pilots may choose Start 1 but as a Run guy I never use Start 1 unless for a specific reason or trying to find a particular problem. Wink

Rigamortis wrote:

The fuel control has 3 valves that send set amounts of fuel to the JFS to get it to spin faster and faster to certain percentagesof speed. The final spin speed is at 110 % to compensate for the torque of the engine shaft. The engine has to be at 28% on the cockpit RPM gauge and the pilot/run man "goes over the horn" with the throttle to idle.

What engine are you talking about 28%? GE's go over the horn at 20% and if the tempeture is greater than 90F than you max motor the JFS and should recieve engine light-off within the allotd time based on what the chart in the 70JG says. I've never heard of going all the way to 28%, unless it's for a max motor.

Last edited by IDCrewDawg on Sep 04, 2005 - 11:26 AM; edited 1 time in total

the JFS is the engine he was talking about. and you can start the aircraft in main power with an ESS controler installed. With the DESSC that isn't possible.

* EDIT * I ment you can start the aircraft in battery with a ESS controler, not a DESSC.

VIPERFIXXER81 wrote:

Actually the Jet has to be started in MAIN PWR and usaully only start 2 is selected.

Actually, it starts just fine on with the Main Power switch in "Battery", but it's self critiquing when the generators don't come on line... Not that I've ever done that before, or anything! Embarassed

We actually had a guy call a Redball for a PTO shaft shear just after start when neither of the generators came on line. Turns out he forgot to switch to Main Power for start!

It's actually pretty easy to do, since just befor starting, you put the Main Power Switch in "Battery" and then put the FLCS Power Test Switch to "Test" to make sure the battery can power all 4 FLCS Branches. Then you're supposed to put the Main Power switch in "Main Power" and start the JFS, but sometimes guys forget.

IDCrewDawg wrote:

You are correct, it was used to start the F-4, and the T-37, other wise the cart had to be used.

Actually, it's used to start the T-38. The T-37 has it's own starter, which is nice on cross-country flights, since you don't have to land somewhere that has a start-cart!

(apparently I like the word "Actually") Confused

Well there is nothin wrong with startin a jet in start 1...least that i've ever heard. On maintence runs or for trouble shootin reasons I always start in 1.. gives me a second chance without the poor guys down there pumping!! But other then that we've had a lot of JFS problems up here. The tech reps say its to do with altitude coupled with the temps.. They tried to find a chart that explained it. Somthin about losin like 1HP or somthin like that per 1000 feet and then somthin to do with the temp dropin that number down as well. Any of ya'll heard of somthin to this effect? I know i've prolly got the numbers wrong...but I know it was somthin like that.

On Alpha's and Bravo's, start one was used for ground start assuming accumulator plus or minus 150-200 psi, start two was used for simulated air start (FCF), or cold day starting. That's if I remember correctly, PW F100-200 powerplant.

Hey, NewCrewChief. I went through Shep a couple years back. Fun place. In regards to another question about pumping up the JFS, it was around 200 pumps. It feels like 2000 though. That was a task we HAD to enjoy at Shep. It's even more fun at Luke. We had at least one JFS crap out per launch. Enjoy!

And speaking of crapping out... went on a TDY this summer and we were on the ramp behind some A-6's. Since we were at a AFB they had to use -60's to start and the fun began. First plane they tried to start, not enough air from the -60. AGE brought them another -60. Same. -60 number three...ditto. Finally number 4 got them going. We're sitting there twiddling our thumbs waiting. Now it's our turn. JFS start 2, she lights up and we launch her out. Done. Starting on the first try with a two man ground crew vs. their mini-circus of about 20 people. God I love the F-16!

i would tell the pilots to go start 1 when we had a JFS no start. it usually works

Forum: F-16 Procedures

Starting the F-16